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1. Measurement of the anomalous precession frequency of the muon in the Fermilab Muon <math><mi>g</mi><mo>−</mo><mn>2</mn></math> Experiment

Author: P. Bloom, P. Kammel, Timothy Chupp, C. Schlesier, P. Girotti, M. J. Lee, A. Nath, Frederick Gray, C. Gabbanini, D. Shemyakin, C. C. Polly, L. Cotrozzi, V. N. Duginov, G. Venanzoni, T. Stuttard, G. Lukicov, M. Iacovacci, H. E. Swanson, T. P. Gorringe, B. C.K. Casey, J. Grange, N. H. Tran, K. W. Hong, K. T. Pitts, R. T. Chislett, Fabrizio Marignetti, A. Lucà, Martin Fertl, E. Barlas-Yucel, J. George, A. Kuchibhotla, Dariush Hampai, T. Walton, D. Cauz, G. Sweetmore, J. Bono, I. R. Bailey, Dinko Pocanic, J. L. Holzbauer, Gavin Grant Hesketh, J. L. Ritchie, Alexander Keshavarzi, H. P. Binney, A. García, Manolis Kargiantoulakis, A. Basti, Barry King, B. MacCoy, M. Kiburg, David Rubin, Alexey Anisenkov, V. Tishchenko, Marin Karuza, H. Nguyen, P. Di Meo, Claudio Ferrari, N. Kinnaird, Liang Li, L. K. Gibbons, N. Raha, R. Chakraborty, D. Flay, R. N. Pilato, M. Incagli, M. Lancaster, Michael Syphers, S. Baeßler, T. J. V. Bowcock, J. LaBounty, G. M. Piacentino, D. Vasilkova, S. Park, A. Lusiani, T. Albahri, R. Madrak, Z. Hodge, Dominik Stöckinger, A. Chapelain, Brad Plaster, R. M. Carey, Dongdong Li, J. D. Crnkovic, D. W. Hertzog, Selcuk Haciomeroglu, J. P. Miller, Andrzej Wolski, Tabitha Halewood-leagas, Franco Bedeschi, B. L. Roberts, S. Grant, J. Fry, Kyoko Makino, J.B. Hempstead, S. Di Falco, K. S. Khaw, W. Turner, Z. Chu, A. T. Herrod, J. D. Price, T. Barrett, N. V. Khomutov, M. Farooq, P. Winter, J. Stapleton, R. Fatemi, D. Kawall, S. Charity, L. Santi, A. Schreckenberger, E. Valetov, B. Quinn, Yannis K. Semertzidis, B. Li, K. L. Giovanetti, A. E. Tewsley-Booth, S. Lee, Ran Hong, S. Leo, M. D. Galati, A.T. Fienberg, Sultan B. Dabagov, S. P. Chang, L. Kelton, G. Pauletta, Rachel Osofsky, G. Di Sciascio, S. Ganguly, D.A. Sweigart, Meghna Bhattacharya, Thomas Teubner, A. Gioiosa, S. Miozzi, B. Kiburg, J. Esquivel, A. Lorente Campos, David Kessler, E. Bottalico, M. Sorbara, Christopher Stoughton, J. Mott, Kayleigh Anne Thomson, Giovanni Cantatore, A. Fioretti, A. Anastasi, Wanwei Wu, Karie Badgley, S. Mastroianni, O. Kim, William Morse, L. Welty-Rieger, A. L. Lyon, A. Hibbert, A. Weisskopf, P. T. Debevec, W. Gohn, E. J. Ramberg, R. Di Stefano, E. Kraegeloh, Martin Berz, Z. Khechadoorian, S. Ramachandran, D. Stratakis, S. Corrodi, D. A. Tarazona, V. A. Baranov, J. Choi, F. Han, Nicholas A. Pohlman, M. Eads, I. Logashenko, N. A. Kuchinskiy, M. W. Smith, Y. I. Kim, A. Driutti, J. Kaspar, K. R. Labe, N. S. Froemming, E. Frlež, Albahri, T., Anastasi, A., Anisenkov, A., Badgley, K., Baeßler, S., Bailey, I., Baranov, V. A., Barlas-Yucel, E., Barrett, T., Basti, A., Bedeschi, F., Berz, M., Bhattacharya, M., Binney, H. P., Bloom, P., Bono, J., Bottalico, E., Bowcock, T., Cantatore, G., Carey, R. M., Casey, B. C. K., Cauz, D., Chakraborty, R., Chang, S. P., Chapelain, A., Charity, S., Chislett, R., Choi, J., Chu, Z., Chupp, T. E., Corrodi, S., Cotrozzi, L., Crnkovic, J. D., Dabagov, S., Debevec, P. T., Di Falco, S., Di Meo, P., Di Sciascio, G., Di Stefano, R., Driutti, A., Duginov, V. N., Eads, M., Esquivel, J., Farooq, M., Fatemi, R., Ferrari, C., Fertl, M., Fienberg, A. T., Fioretti, A., Flay, D., Frlež, E., Froemming, N. S., Fry, J., Gabbanini, C., Galati, M. D., Ganguly, S., Garcia, A., George, J., Gibbons, L. K., Gioiosa, A., Giovanetti, K. L., Girotti, P., Gohn, W., Gorringe, T., Grange, J., Grant, S., Gray, F., Haciomeroglu, S., Halewood-Leagas, T., Hampai, D., Han, F., Hempstead, J., Herrod, A. T., Hertzog, D. W., Hesketh, G., Hibbert, A., Hodge, Z., Holzbauer, J. L., Hong, K. W., Hong, R., Iacovacci, M., Incagli, M., Kammel, P., Kargiantoulakis, M., Karuza, M., Kaspar, J., Kawall, D., Kelton, L., Keshavarzi, A., Kessler, D., Khaw, K. S., Khechadoorian, Z., Khomutov, N. V., Kiburg, B., Kiburg, M., Kim, O., Kim, Y. I., King, B., Kinnaird, N., Kraegeloh, E., Kuchibhotla, A., Kuchinskiy, N. A., Labe, K. R., Labounty, J., Lancaster, M., Lee, M. J., Lee, S., Leo, S., Li, B., Li, D., Li, L., Logashenko, I., Lorente Campos, A., Lucà, A., Lukicov, G., Lusiani, A., Lyon, A. L., Maccoy, B., Madrak, R., Makino, K., Marignetti, F., Mastroianni, S., Miller, J. P., Miozzi, S., Morse, W. M., Mott, J., Nath, A., Nguyen, H., Osofsky, R., Park, S., Pauletta, G., Piacentino, G. M., Pilato, R. N., Pitts, K. T., Plaster, B., Počanić, D., Pohlman, N., Polly, C. C., Price, J., Quinn, B., Raha, N., Ramachandran, S., Ramberg, E., Ritchie, J. L., Roberts, B. L., Rubin, D. L., Santi, L., Schlesier, C., Schreckenberger, A., Semertzidis, Y. K., Shemyakin, D., Smith, M. W., Sorbara, M., Stöckinger, D., Stapleton, J., Stoughton, C., Stratakis, D., Stuttard, T., Swanson, H. E., Sweetmore, G., Sweigart, D. A., Syphers, M. J., Tarazona, D. A., Teubner, T., Tewsley-Booth, A. E., Thomson, K., Tishchenko, V., Tran, N. H., Turner, W., Valetov, E., Vasilkova, D., Venanzoni, G., Walton, T., Weisskopf, A., Welty-Rieger, L., Winter, P., Wolski, A., and Wu, W.
Subjects: Physics::Instrumentation and Detectors, Measure (physics), FOS: Physical sciences, 7. Clean energy, 01 natural sciences, Omega, High Energy Physics - Experiment, Nuclear physics, Nuclear Experiment, High Energy Physics - Experiment (hep-ex), muon, 0103 physical sciences, Fermilab, Nuclear Experiment (nucl-ex), 010306 general physics, Larmor precession, Physics, Muon, 010308 nuclear & particles physics, Settore FIS/01 - Fisica Sperimentale, anomalous magnetic moment, 3. Good health, Magnetic field, Physics::Accelerator Physics, High Energy Physics::Experiment, Storage ring, Fermi Gamma-ray Space Telescope
Abstract: The Muon g-2 Experiment at Fermi National Accelerator Laboratory (FNAL) has measured the muon anomalous precession frequency $\omega_a$ to an uncertainty of 434 parts per billion (ppb), statistical, and 56 ppb, systematic, with data collected in four storage ring configurations during its first physics run in 2018. When combined with a precision measurement of the magnetic field of the experiment's muon storage ring, the precession frequency measurement determines a muon magnetic anomaly of $a_{\mu}({\rm FNAL}) = 116\,592\,040(54) \times 10^{-11}$ (0.46 ppm). This article describes the multiple techniques employed in the reconstruction, analysis and fitting of the data to measure the precession frequency. It also presents the averaging of the results from the eleven separate determinations of \omega_a, and the systematic uncertainties on the result., Comment: 29 pages, 19 figures. Published in Physical Review D
Published: 2021

2. Beam Spin Asymmetry in Semi-Inclusive Electroproduction of Hadron Pairs

Author: K. Park, V. P. Kubarovsky, Krishna Neupane, C. W. Kim, H. Avakian, H. Voskanyan, W. J. Briscoe, Dustin Keller, P. Eugenio, Michael Wood, K. Hafidi, G. Gavalian, L. Marsicano, A Hobart, V. Mokeev, F. X. Girod, R. A. Schumacher, M. Battaglieri, I. I. Strakovsky, R. W. Gothe, T. Chetry, M. J. Amaryan, F. Sabatié, K. Wei, S. Fegan, N. Markov, L. Guo, Alessandro Rizzo, K. A. Griffioen, Fatiha Benmokhtar, Gerard Gilfoyle, R. Paremuzyan, E. L. Isupov, A. Deur, S. Pisano, V. Crede, Ross Milner, O. Soto, P. Lenisa, M. Contalbrigo, C. Dilks, L. Lanza, M. Ungaro, T. A. Forest, C. Mullen, W. K. Brooks, M. Guidal, Z. W. Zhao, S. Stepanyan, N. A. Baltzell, M. Holtrop, T. B. Hayward, Friedrich Klein, Andrea Celentano, O. Pogorelko, J. Poudel, A. Filippi, Brian Raue, K. Hicks, K. Joo, D. Marchand, M. Osipenko, Luciano Pappalardo, K. L. Giovanetti, Hovanes Egiyan, M. Ripani, C. Munoz Camacho, A. D'Angelo, B. Yale, S. Adhikari, L. Venturelli, B. McKinnon, M. Ehrhart, D. G. Ireland, Tim O'Connell, I. Bedlinskiy, D. I. Glazier, W. Phelps, D. G. Jenkins, N. Tyler, M. Leali, L. El Fassi, C. Djalali, Volker D. Burkert, W. Kim, T. Mineeva, D. Heddle, R. De Vita, G. Ciullo, V. Mascagna, H. S. Jo, A. S. Biselli, M. Mirazita, D. Bulumulla, Y. Prok, D. S. Carman, G. Niculescu, B. S. Ishkhanov, E. Pasyuk, Aditya R. Khanal, X. Wei, R. G. Fersch, Andrea Bianconi, H. Atac, P. L. Cole, N. Dashyan, G. Angelini, P. Chatagnon, B. A. Clary, P. Rossi, M. Defurne, Michael Paolone, L. Barion, Axel Schmidt, Aurore Courtoy, K. Livingston, M. Khandaker, Jie Zhang, I. J. D. MacGregor, E. Golovatch, R. Dupre, Y. Ghandilyan, Q. Huang, E. Voutier, A. Vossen, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, J. C. Carvajal, S. Strauch, D. P. Watts, F. Bossu, Nikolaos Sparveris, Dinko Pocanic, S. E. Kuhn, M. Hattawy, Y. G. Sharabian, S. Boiarinov, H. Hakobyan, J. Ritman, S. Diehl, C. Salgado, U. Shrestha, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS
Subjects: High Energy Physics::Lattice, Nuclear Theory, Hadron, parton: distribution function, General Physics and Astronomy, Parton, 01 natural sciences, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Economica, higher-twist, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), electron: beam, Nuclear Experiment, dimension: 1, Physics, Quantum chromodynamics, deep inelastic scattering: semi-inclusive reaction, Settore FIS/04, nucleon, kinematics, Quarks and Gluons, helicity distributions, quark: valence, Nucleon, Jefferson Lab, Quark, Particle physics, polarization: longitudinal, FOS: Physical sciences, Socio-culturale, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Transversity Distributions, hadron: electroproduction, hadron: pair production, Pion, CLAS, Hadron Physics, quantum chromodynamics, 0103 physical sciences, ddc:530, 010306 general physics, High Energy Physics::Phenomenology, Ambientale, Deep inelastic scattering, spin: asymmetry: measured, Distribution function, Elementary Particles and Fields, QCD Dynamics, High Energy Physics::Experiment, pi: pair production, experimental results
Abstract: Physical review letters 126(6), 062002 (2021). doi:10.1103/PhysRevLett.126.062002, Published by APS, College Park, Md.
Published: 2021

3. Measurement of the proton spin structure at long distances

Author: P. Eugenio, J. Brock, N. Dashyan, I. Bedlinskiy, S. Choi, P. Nadel-Turonski, A. Hobart, M. Defurne, S. E. Kuhn, Latifa Elouadrhiri, P. Chatagnon, M. Ripani, C. D. Keith, D. Bulumulla, Aditya R. Khanal, S. Adhikari, B. McKinnon, T. Holmstrom, V. Mokeev, G. V. Fedotov, H. S. Jo, L. Guo, Alessandro Rizzo, Andrea Bianconi, L. Barion, M. Mirazita, K. Livingston, M. Hattawy, N. Markov, G. Rosner, Simon Širca, S. Fegan, Y. Ghandilyan, Jie Zhang, P. Bosted, Michael Paolone, C. Carlin, M. Guidal, M. L. Seely, E. Pasyuk, D. P. Watts, F. Bossu, Laura Clark, S. Niccolai, N. Guler, M. Holtrop, B. Yale, R. A. Schumacher, P. Rossi, W. Phelps, V. Mascagna, S. Joosten, Axel Schmidt, Alexandre Deur, Luciano Pappalardo, Nikolaos Sparveris, V. Crede, I. I. Strakovsky, W. Kim, Fatiha Benmokhtar, M. Ehrhart, D. I. Glazier, V. P. Kubarovsky, T. A. Forest, O. Pogorelko, Z. W. Zhao, J. Rowley, S. Stepanyan, A. I. Ostrovidov, K. Park, Krishna Neupane, R. De Vita, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, D. G. Ireland, C. W. Kim, H. Avakian, C. Mullen, W. K. Brooks, A. Kripko, Andrea Celentano, Volker D. Burkert, A. S. Biselli, J. C. Carvajal, V. Sulkosky, H. Atac, Karl Slifer, M. Leali, F. Sabatié, L. Venturelli, Y. G. Sharabian, X. Zheng, M. Bondì, H. Voskanyan, P. Lenisa, W. J. Briscoe, I. J. D. MacGregor, M. Contalbrigo, S. K. Phillips, T. Mineeva, T. B. Hayward, Friedrich Klein, Brian Raue, J. Poudel, N. Tyler, C. Djalali, G. Ciullo, M. Osipenko, Y. Prok, D. S. Carman, X. Wei, K. A. Griffioen, E. Voutier, Dustin Keller, S. Strauch, L. Lanza, R. W. Gothe, Michael Wood, T. Chetry, K. Hafidi, R. Dupre, M. Battaglieri, Gerard Gilfoyle, E. L. Isupov, V. A. Drozdov, S. Boiarinov, H. Kang, U. Shrestha, F.-X. Girod, K. P. Adhikari, H. Hakobyan, J. Ritman, S. Diehl, C. Salgado, R. G. Fersch, M. Ungaro, E. Long, J. P. Chen, D. Heddle, P. L. Cole, D. G. Meekins, A. D'Angelo, K. Hicks, L. El Fassi, K. Joo, M. Khandaker, M. J. Amaryan, A. Filippi, K. L. Giovanetti, Larry Weinstein, L. Marsicano, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS
Subjects: polarizabilities, Photon, Proton, High Energy Physics::Lattice, Nuclear Theory, General Physics and Astronomy, polarized target, polarized beam, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, High Energy Physics - Experiment, Theoretical Nuclear Physics, Experimental Nuclear Physics, High Energy Physics - Experiment (hep-ex), effective field theory, Economica, Proton spin crisis, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Experimental particle Physics, order, Nuclear Experiment (nucl-ex), Nuclear Experiment, Spin-½, Quantum chromodynamics, Physics, Settore FIS/04, nucleon, virtual compton-scattering, chiral perturbation-theory, sum-rule, moments, evolution, sum rule, kinematics, Quantum electrodynamics, nuclear matter, Nucleon, nucleon: structure, Strong interaction, FOS: Physical sciences, Socio-culturale, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], p: spin, PE2_2, momentum transfer: low, PE2_1, CLAS, 0103 physical sciences, quantum chromodynamics, ddc:530, 010306 general physics, PE2_3, quark gluon, Coupling constant, nuclear force, scattering, Ambientale, Physics::Accelerator Physics, nucleon: spin, High Energy Physics::Experiment, experimental results
Abstract: Measuring the spin structure of protons and neutrons tests our understanding of how they arise from quarks and gluons, the fundamental building blocks of nuclear matter. At long distances the coupling constant of the strong interaction becomes large, requiring non-perturbative methods to calculate quantum chromodynamics processes, such as lattice gauge theory or effective field theories. Here we report proton spin structure measurements from scattering a polarized electron beam off polarized protons. The spin-dependent cross-sections were measured at large distances, corresponding to the region of low momentum transfer squared between 0.012 and 1.0 GeV$^2$. This kinematic range provides unique tests of chiral effective field theory predictions. Our results show that a complete description of the nucleon spin remains elusive, and call for further theoretical works, e.g. in lattice quantum chromodynamics. Finally, our data extrapolated to the photon point agree with the Gerasimov-Drell-Hearn sum rule, a fundamental prediction of quantum field theory that relates the anomalous magnetic moment of the proton to its integrated spin-dependent cross-sections., Published version. 10 pages, 5 figures. 20 pages of supplementary material (data tables and a figure)
Published: 2021

4. Measurement of the anomalous precession frequency of the muon in the Fermilab Muon Experiment

Author: T. Albahri, A. Anastasi, A. Anisenkov, K. Badgley, S. Bae??ler, I. Bailey, V. ???A. Baranov, E. Barlas-Yucel, T. Barrett, A. Basti, F. Bedeschi, M. Berz, M. Bhattacharya, H. ???P. Binney, P. Bloom, J. Bono, E. Bottalico, T. Bowcock, G. Cantatore, R. ???M. Carey, B. ???C. ???K. Casey, D. Cauz, R. Chakraborty, S. ???P. Chang, A. Chapelain, S. Charity, R. Chislett, J. Choi, Z. Chu, T. ???E. Chupp, S. Corrodi, L. Cotrozzi, J. ???D. Crnkovic, S. Dabagov, P. ???T. Debevec, S. Di Falco, P. Di Meo, G. Di Sciascio, R. Di Stefano, A. Driutti, V. ???N. Duginov, M. Eads, J. Esquivel, M. Farooq, R. Fatemi, C. Ferrari, M. Fertl, A. ???T. Fienberg, A. Fioretti, D. Flay, E. Frle??, N. ???S. Froemming, J. Fry, C. Gabbanini, M. ???D. Galati, S. Ganguly, A. Garcia, J. George, L. ???K. Gibbons, A. Gioiosa, K. ???L. Giovanetti, P. Girotti, W. Gohn, T. Gorringe, J. Grange, S. Grant, F. Gray, S. Haciomeroglu, T. Halewood-Leagas, D. Hampai, F. Han, J. Hempstead, A. ???T. Herrod, D. ???W. Hertzog, G. Hesketh, A. Hibbert, Z. Hodge, J. ???L. Holzbauer, K. ???W. Hong, R. Hong, M. Iacovacci, M. Incagli, P. Kammel, M. Kargiantoulakis, M. Karuza, J. Kaspar, D. Kawall, L. Kelton, A. Keshavarzi, D. Kessler, K. ???S. Khaw, Z. Khechadoorian, N. ???V. Khomutov, B. Kiburg, M. Kiburg, O. Kim, Y. ???I. Kim, B. King, N. Kinnaird, E. Kraegeloh, A. Kuchibhotla, N. ???A. Kuchinskiy, K. ???R. Labe, J. LaBounty, M. Lancaster, M. ???J. Lee, S. Lee, S. Leo, B. Li, D. Li, L. Li, I. Logashenko, A. Lorente Campos, A. Luc??, G. Lukicov, A. Lusiani, A. ???L. Lyon, B. MacCoy, R. Madrak, K. Makino, F. Marignetti, S. Mastroianni, J. ???P. Miller, S. Miozzi, W. ???M. Morse, J. Mott, A. Nath, H. Nguyen, R. Osofsky, S. Park, G. Pauletta, G. ???M. Piacentino, R. ???N. Pilato, K. ???T. Pitts, B. Plaster, D. Po??ani??, N. Pohlman, C. ???C. Polly, J. Price, B. Quinn, N. Raha, S. Ramachandran, E. Ramberg, J. ???L. Ritchie, B. ???L. Roberts, D. ???L. Rubin, L. Santi, C. Schlesier, A. Schreckenberger, Y. ???K. Semertzidis, D. Shemyakin, M. ???W. Smith, M. Sorbara, D. St??ckinger, J. Stapleton, C. Stoughton, D. Stratakis, T. Stuttard, H. ???E. Swanson, G. Sweetmore, D. ???A. Sweigart, M. ???J. Syphers, D. ???A. Tarazona, T. Teubner, A. ???E. Tewsley-Booth, K. Thomson, V. Tishchenko, N. ???H. Tran, W. Turner, E. Valetov, D. Vasilkova, G. Venanzoni, T. Walton, A. Weisskopf, L. Welty-Rieger, P. Winter, A. Wolski, W. Wu, Albahri, T., Anastasi, A., Anisenkov, A., Badgley, K., Bae??ler, S., Bailey, I., Baranov, V. ???A., Barlas-Yucel, E., Barrett, T., Basti, A., Bedeschi, F., Berz, M., Bhattacharya, M., Binney, H. ???P., Bloom, P., Bono, J., Bottalico, E., Bowcock, T., Cantatore, G., Carey, R. ???M., Casey, B. ???C. ???K., Cauz, D., Chakraborty, R., Chang, S. ???P., Chapelain, A., Charity, S., Chislett, R., Choi, J., Chu, Z., Chupp, T. ???E., Corrodi, S., Cotrozzi, L., Crnkovic, J. ???D., Dabagov, S., Debevec, P. ???T., Di Falco, S., Di Meo, P., Di Sciascio, G., Di Stefano, R., Driutti, A., Duginov, V. ???N., Eads, M., Esquivel, J., Farooq, M., Fatemi, R., Ferrari, C., Fertl, M., Fienberg, A. ???T., Fioretti, A., Flay, D., Frle??, E., Froemming, N. ???S., Fry, J., Gabbanini, C., Galati, M. ???D., Ganguly, S., Garcia, A., George, J., Gibbons, L. ???K., Gioiosa, A., Giovanetti, K. ???L., Girotti, P., Gohn, W., Gorringe, T., Grange, J., Grant, S., Gray, F., Haciomeroglu, S., Halewood-Leagas, T., Hampai, D., Han, F., Hempstead, J., Herrod, A. ???T., Hertzog, D. ???W., Hesketh, G., Hibbert, A., Hodge, Z., Holzbauer, J. ???L., Hong, K. ???W., Hong, R., Iacovacci, M., Incagli, M., Kammel, P., Kargiantoulakis, M., Karuza, M., Kaspar, J., Kawall, D., Kelton, L., Keshavarzi, A., Kessler, D., Khaw, K. ???S., Khechadoorian, Z., Khomutov, N. ???V., Kiburg, B., Kiburg, M., Kim, O., Kim, Y. ???I., King, B., Kinnaird, N., Kraegeloh, E., Kuchibhotla, A., Kuchinskiy, N. ???A., Labe, K. ???R., Labounty, J., Lancaster, M., Lee, M. ???J., Lee, S., Leo, S., Li, B., Li, D., Li, L., Logashenko, I., Lorente Campos, A., Luc??, A., Lukicov, G., Lusiani, A., Lyon, A. ???L., Maccoy, B., Madrak, R., Makino, K., Marignetti, F., Mastroianni, S., Miller, J. ???P., Miozzi, S., Morse, W. ???M., Mott, J., Nath, A., Nguyen, H., Osofsky, R., Park, S., Pauletta, G., Piacentino, G. ???M., Pilato, R. ???N., Pitts, K. ???T., Plaster, B., Po??ani??, D., Pohlman, N., Polly, C. ???C., Price, J., Quinn, B., Raha, N., Ramachandran, S., Ramberg, E., Ritchie, J. ???L., Roberts, B. ???L., Rubin, D. ???L., Santi, L., Schlesier, C., Schreckenberger, A., Semertzidis, Y. ???K., Shemyakin, D., Smith, M. ???W., Sorbara, M., St??ckinger, D., Stapleton, J., Stoughton, C., Stratakis, D., Stuttard, T., Swanson, H. ???E., Sweetmore, G., Sweigart, D. ???A., Syphers, M. ???J., Tarazona, D. ???A., Teubner, T., Tewsley-Booth, A. ???E., Thomson, K., Tishchenko, V., Tran, N. ???H., Turner, W., Valetov, E., Vasilkova, D., Venanzoni, G., Walton, T., Weisskopf, A., Welty-Rieger, L., Winter, P., Wolski, A., and Wu, W.
Abstract: The Muon g−2 Experiment at Fermi National Accelerator Laboratory (FNAL) has measured the muon anomalous precession frequency ωma to an uncertainty of 434 parts per billion (ppb), statistical, and 56 ppb, systematic, with data collected in four storage ring configurations during its first physics run in 2018. When combined with a precision measurement of the magnetic field of the experiment’s muon storage ring, the precession frequency measurement determines a muon magnetic anomaly of aμ(FNAL)=116592040(54)×10−11 (0.46 ppm). This article describes the multiple techniques employed in the reconstruction, analysis, and fitting of the data to measure the precession frequency. It also presents the averaging of the results from the 11 separate determinations of ωma, and the systematic uncertainties on the result.
Published: 2021

5. Magnetic Field Measurement and Analysis for the Muon g-2 Experiment at Fermilab

Author: Z. Chu, M. Eads, M. Lancaster, T. Halewood-Leagas, D. Flay, I. Logashenko, N. A. Kuchinskiy, M. W. Smith, Y. I. Kim, S.B. Dabagov, B. MacCoy, N. H. Tran, K. W. Hong, Liang Li, L. Santi, A. Chapelain, K. S. Khaw, K. T. Pitts, R. Fatemi, I. R. Bailey, E. Bottalico, Andrzej Wolski, R. N. Pilato, P. Bloom, M. Iacovacci, G. Pauletta, M. Incagli, R. Di Stefano, Timothy Chupp, E. Barlas-Yucel, G. Di Sciascio, G. Sweetmore, D. Cauz, P. Girotti, H. Nguyen, Thomas Teubner, D.A. Sweigart, A. E. Tewsley-Booth, G. Piacentino, D. Stöckinger, Karie Badgley, L. Kelton, P. Winter, Brad Plaster, J. L. Holzbauer, R. Chislett, B. Quinn, R. M. Carey, A. Conway, Kyoko Makino, A. Hibbert, B. C. K. Casey, A. Driutti, J. George, A. Lorente Campos, W. Turner, A. Lucà, S. Ramachandran, W. Wu, G. Hesketh, E. Valetov, E. Kraegeloh, Franco Bedeschi, A. Gioiosa, P. T. Debevec, L. Cotrozzi, V. N. Duginov, S. Corrodi, S. Miozzi, Yannis K. Semertzidis, M. J. Lee, S. Mastroianni, P. Di Meo, Martin Berz, K. L. Giovanetti, D. Stratakis, G. Lukicov, C. Gabbanini, J.B. Hempstead, A. Weisskopf, V. Tishchenko, B. Kiburg, H. E. Swanson, O. Kim, Michael Syphers, R. Osofsky, T. Stuttard, J. Esquivel, Dariush Hampai, T. J. V. Bowcock, Adam L. Lyon, Z. Khechadoorian, Meghna Bhattacharya, T. Barrett, Martin Fertl, D. Shemyakin, V. A. Baranov, Manolis Kargiantoulakis, R. Madrak, Marin Karuza, D. Vasilkova, S. Park, N. Kinnaird, A. Lusiani, T. Albahri, E. Ramberg, Nicholas A. Pohlman, D. Kawall, A. Schreckenberger, J. L. Ritchie, A. T. Herrod, Selcuk Haciomeroglu, L. K. Gibbons, J. Stapleton, Fabrizio Marignetti, K. Thomson, J. LaBounty, W. Gohn, G. Venanzoni, B. Li, Claudio Ferrari, Dinko Pocanic, S. P. Chang, S. Charity, T. Walton, T. P. Gorringe, Benjamin T. King, A. Fioretti, A. Anastasi, Sudeshna Ganguly, S. Lee, Ran Hong, M. D. Galati, A.T. Fienberg, William Morse, L. Welty-Rieger, Alejandro Garcia, J. Grange, J. Choi, Dongdong Li, D. W. Hertzog, A. Keshavarzi, M. Sorbara, F. Han, J. Bono, J. Mott, P. Kammel, C. Schlesier, Giovanni Cantatore, S. Di Falco, R. Chakraborty, C. C. Polly, J. P. Miller, M. Kiburg, J. Kaspar, David Rubin, S. Baeßler, K. R. Labe, N. S. Froemming, H. P. Binney, B. L. Roberts, S. Grant, J. Price, N. Raha, Z. Hodge, N. V. Khomutov, M. Farooq, Jason Crnkovic, D. A. Tarazona, C. Stoughton, A. Nath, Frederick Gray, David Kessler, Albahri, T., Anastasi, A., Badgley, K., Baessler, S., Bailey, I., Baranov, V. A., Barlas-Yucel, E., Barrett, T., Bedeschi, F., Berz, M., Bhattacharya, M., Binney, H. P., Bloom, P., Bono, J., Bottalico, E., Bowcock, T., Cantatore, G., Carey, R. M., Casey, B. C. K., Cauz, D., Chakraborty, R., Chang, S. P., Chapelain, A., Charity, S., Chislett, R., Choi, J., Chu, Z., Chupp, T. E., Conway, A., Corrodi, S., Cotrozzi, L., Crnkovic, J. D., Dabagov, S., Debevec, P. T., Di Falco, S., Di Meo, P., Di Sciascio, G., Di Stefano, R., Driutti, A., Duginov, V. N., Eads, M., Esquivel, J., Farooq, M., Fatemi, R., Ferrari, C., Fertl, M., Fienberg, A. T., Fioretti, A., Flay, D., Froemming, N. S., Gabbanini, C., Galati, M. D., Ganguly, S., Garcia, A., George, J., Gibbons, L. K., Gioiosa, A., Giovanetti, K. L., Girotti, P., Gohn, W., Gorringe, T., Grange, J., Grant, S., Gray, F., Haciomeroglu, S., Halewood-Leagas, T., Hampai, D., Han, F., Hempstead, J., Herrod, A. T., Hertzog, D. W., Hesketh, G., Hibbert, A., Hodge, Z., Holzbauer, J. L., Hong, K. W., Hong, R., Iacovacci, M., Incagli, M., Kammel, P., Kargiantoulakis, M., Karuza, M., Kaspar, J., Kawall, D., Kelton, L., Keshavarzi, A., Kessler, D., Khaw, K. S., Khechadoorian, Z., Khomutov, N. V., Kiburg, B., Kiburg, M., Kim, O., Kim, Y. I., King, B., Kinnaird, N., Kraegeloh, E., Kuchinskiy, N. A., Labe, K. R., Labounty, J., Lancaster, M., Lee, M. J., Lee, S., Li, B., Li, D., Li, L., Logashenko, I., Lorente Campos, A., Luca, A., Lukicov, G., Lusiani, A., Lyon, A. L., Maccoy, B., Madrak, R., Makino, K., Marignetti, F., Mastroianni, S., Miller, J. P., Miozzi, S., Morse, W. M., Mott, J., Nath, A., Nguyen, H., Osofsky, R., Park, S., Pauletta, G., Piacentino, G. M., Pilato, R. N., Pitts, K. T., Plaster, B., Pocanic, D., Pohlman, N., Polly, C. C., Price, J., Quinn, B., Raha, N., Ramachandran, S., Ramberg, E., Ritchie, J. L., Roberts, B. L., Rubin, D. L., Santi, L., Schlesier, C., Schreckenberger, A., Semertzidis, Y. K., Shemyakin, D., Smith, M. W., Sorbara, M., Stockinger, D., Stapleton, J., Stoughton, C., Stratakis, D., Stuttard, T., Swanson, H. E., Sweetmore, G., Sweigart, D. A., Syphers, M. J., Tarazona, D. A., Teubner, T., Tewsley-Booth, A. E., Thomson, K., Tishchenko, V., Tran, N. H., Turner, W., Valetov, E., Vasilkova, D., Venanzoni, G., Walton, T., Weisskopf, A., Welty-Rieger, L., Winter, P., Wolski, A., Wu, W., Baeßler, S., Lucà, A., Počanić, D., and Stöckinger, D.
Subjects: Field (physics), Physics::Instrumentation and Detectors, FOS: Physical sciences, 7. Clean energy, 01 natural sciences, Omega, High Energy Physics - Experiment, 010305 fluids & plasmas, Nuclear physics, High Energy Physics - Experiment (hep-ex), muon, 0103 physical sciences, Proton spin crisis, Fermilab, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Larmor precession, Physics, Muon, Settore FIS/01 - Fisica Sperimentale, VACUUM POLARIZATION CONTRIBUTIONSTEMPERATURE-DEPENDENCEPROTON NMRMOMENTSUSCEPTIBILITYTERMS, anomalous magnetic moment, Muon g-2 Experiment, anomalous precession frequency, Magnetic field, anomalous precession frequency, Muon g-2 Experiment, Fermi Gamma-ray Space Telescope
Abstract: The Fermi National Accelerator Laboratory has measured the anomalous precession frequency $a^{}_\mu = (g^{}_\mu-2)/2$ of the muon to a combined precision of 0.46 parts per million with data collected during its first physics run in 2018. This paper documents the measurement of the magnetic field in the muon storage ring. The magnetic field is monitored by nuclear magnetic resonance systems and calibrated in terms of the equivalent proton spin precession frequency in a spherical water sample at 34.7$^\circ$C. The measured field is weighted by the muon distribution resulting in $\tilde{\omega}'^{}_p$, the denominator in the ratio $\omega^{}_a$/$\tilde{\omega}'^{}_p$ that together with known fundamental constants yields $a^{}_\mu$. The reported uncertainty on $\tilde{\omega}'^{}_p$ for the Run-1 data set is 114 ppb consisting of uncertainty contributions from frequency extraction, calibration, mapping, tracking, and averaging of 56 ppb, and contributions from fast transient fields of 99 ppb., Comment: Added one citation and corrected missing normalization in Eqs (35) and (36)
Published: 2021
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6. Beam dynamics corrections to the Run-1 measurement of the muon anomalous magnetic moment at Fermilab

Author: K. S. Khaw, C. Schlesier, Diktys Stratakis, R. Fatemi, S. Corrodi, D. Newton, K. T. Pitts, R. T. Chislett, L. K. Gibbons, Kyoko Makino, E. Bottalico, A. Gioiosa, J. LaBounty, J. Bono, I. R. Bailey, P. Kammel, D. Kawall, T. J. V. Bowcock, H. P. Binney, W. Turner, A. T. Herrod, S. Miozzi, A. Schreckenberger, E. Valetov, N. H. Tran, K. W. Hong, J. Esquivel, M. Sorbara, Christopher Stoughton, Fabrizio Marignetti, A. Lucà, L. Kelton, M. Eads, D. Stöckinger, T. Barrett, G. Piacentino, J. Mott, S. Baeßler, Bck Casey, Kayleigh Anne Thomson, Giovanni Cantatore, Rachel Osofsky, M. Kiburg, E. Barlas-Yucel, Michael Syphers, C. C. Polly, J. Choi, R. Chakraborty, D. Flay, David Rubin, J. Grange, N. A. Kuchinskiy, M. W. Smith, G. Lukicov, M. Iacovacci, G. Pauletta, J. L. Ritchie, B. MacCoy, L. Cotrozzi, V. N. Duginov, A. Lorente Campos, S. Lee, Ran Hong, G. Sweetmore, D.A. Sweigart, M. Korostelev, Dongdong Li, D. W. Hertzog, Alexander Keshavarzi, G. Di Sciascio, Alejandro L. Garcia, Liang Li, F. Han, D. Sathyan, A.T. Fienberg, Sultan B. Dabagov, M. J. Lee, S. P. Chang, Benjamin T. King, Marin Karuza, R. N. Pilato, M. Incagli, J.B. Hempstead, B. Quinn, L. Santi, N. Kinnaird, F. Gray, P. Winter, L. Welty-Rieger, Meghna Bhattacharya, H. Nguyen, P. Di Meo, T. Stuttard, A. L. Lyon, David Kessler, A. Chapelain, J. Kaspar, B. Li, Galati, Sudeshna Ganguly, Andrzej Wolski, A. Driutti, D. A. Tarazona, Brad Plaster, R. M. Carey, D. Cauz, G. Venanzoni, J. Fry, B. Kiburg, J. P. Miller, W. Gohn, B. L. Roberts, S. Grant, V. A. Baranov, Nicholas A. Pohlman, N. V. Khomutov, M. Farooq, Jason Crnkovic, A. Hibbert, K. R. Labe, P. T. Debevec, Thomas Teubner, S. Di Falco, J. D. Price, Yi Kim, I.B. Logashenko, Yannis K. Semertzidis, K. L. Giovanetti, A. E. Tewsley-Booth, E. Frlež, Martin Berz, S. Charity, T. Walton, Z. Khechadoorian, S. Ramachandran, A. Fiedler, T. P. Gorringe, William Morse, A. Fioretti, A. Anastasi, O. Kim, A. Weisskopf, Wanwei Wu, Karie Badgley, S. Mastroianni, J. L. Holzbauer, Manolis Kargiantoulakis, S. Park, A. Lusiani, T. Albahri, R. Madrak, Selcuk Haciomeroglu, Z. Chu, Dariush Hampai, Gavin Grant Hesketh, J. George, Tishchenko, D. Vasilkova, Franco Bedeschi, P. Bloom, Timothy Chupp, P. Girotti, Nathan Froemming, J. Stapleton, Dinko Pocanic, M. Lancaster, C. Gabbanini, N. Raha, H. E. Swanson, Martin Fertl, Z. Hodge, Tabitha Halewood-leagas, E. J. Ramberg, A. Nath, R. Di Stefano, E. Kraegeloh, Claudio Ferrari, Albahri, T., Anastasi, A., Badgley, K., Baessler, S., Bailey, I., Baranov, V. A., Barlas-Yucel, E., Barrett, T., Bedeschi, F., Berz, M., Bhattacharya, M., Binney, H. P., Bloom, P., Bono, J., Bottalico, E., Bowcock, T., Cantatore, G., Carey, R. M., Casey, B. C. K., Cauz, D., Chakraborty, R., Chang, S. P., Chapelain, A., Charity, S., Chislett, R., Choi, J., Chu, Z., Chupp, T. E., Corrodi, S., Cotrozzi, L., Crnkovic, J. D., Dabagov, S., Debevec, P. T., Di Falco, S., Di Meo, P., Di Sciascio, G., Di Stefano, R., Driutti, A., Duginov, V. N., Eads, M., Esquivel, J., Farooq, M., Fatemi, R., Ferrari, C., Fertl, M., Fiedler, A., Fienberg, A. T., Fioretti, A., Flay, D., Frlez, E., Froemming, N. S., Fry, J., Gabbanini, C., Galati, M. D., Ganguly, S., Garcia, A., George, J., Gibbons, L. K., Gioiosa, A., Giovanetti, K. L., Girotti, P., Gohn, W., Gorringe, T., Grange, J., Grant, S., Gray, F., Haciomeroglu, S., Halewood-Leagas, T., Hampai, D., Han, F., Hempstead, J., Herrod, A. T., Hertzog, D. W., Hesketh, G., Hibbert, A., Hodge, Z., Holzbauer, J. L., Hong, K. W., Hong, R., Iacovacci, M., Incagli, M., Kammel, P., Kargiantoulakis, M., Karuza, M., Kaspar, J., Kawall, D., Kelton, L., Keshavarzi, A., Kessler, D., Khaw, K. S., Khechadoorian, Z., Khomutov, N. V., Kiburg, B., Kiburg, M., Kim, O., Kim, Y. I., King, B., Kinnaird, N., Korostelev, M., Kraegeloh, E., Kuchinskiy, N. A., Labe, K. R., Labounty, J., Lancaster, M., Lee, M. J., Lee, S., Li, B., Li, D., Li, L., Logashenko, I., Lorente Campos, A., Luca, A., Lukicov, G., Lusiani, A., Lyon, A. L., Maccoy, B., Madrak, R., Makino, K., Marignetti, F., Mastroianni, S., Miller, J. P., Miozzi, S., Morse, W. M., Mott, J., Nath, A., Newton, D., Nguyen, H., Osofsky, R., Park, S., Pauletta, G., Piacentino, G. M., Pilato, R. N., Pitts, K. T., Plaster, B., Pocanic, D., Pohlman, N., Polly, C. C., Price, J., Quinn, B., Raha, N., Ramachandran, S., Ramberg, E., Ritchie, J. L., Roberts, B. L., Rubin, D. L., Santi, L., Sathyan, D., Schlesier, C., Schreckenberger, A., Semertzidis, Y. K., Smith, M. W., Sorbara, M., Stockinger, D., Stapleton, J., Stoughton, C., Stratakis, D., Stuttard, T., Swanson, H. E., Sweetmore, G., Sweigart, D. A., Syphers, M. J., Tarazona, D. A., Teubner, T., Tewsley-Booth, A. E., Thomson, K., Tishchenko, V., Tran, N. H., Turner, W., Valetov, E., Vasilkova, D., Venanzoni, G., Walton, T., Weisskopf, A., Welty-Rieger, L., Winter, P., Wolski, A., and Wu, W.
Subjects: Larmor precession, Physics, Accelerator Physics (physics.acc-ph), Nuclear and High Energy Physics, Muon, Physics and Astronomy (miscellaneous), Anomalous magnetic dipole moment, 010308 nuclear & particles physics, FOS: Physical sciences, Surfaces and Interfaces, 01 natural sciences, High Energy Physics - Experiment, Magnetic field, Nuclear physics, High Energy Physics - Experiment (hep-ex), muon magnetic anomaly, 0103 physical sciences, Physics - Accelerator Physics, Fermilab, Pitch angle, 010306 general physics, G-2 EXPERIMENTFREQUENCY, Storage ring, Beam (structure)
Abstract: This paper presents the beam dynamics systematic corrections and their uncertainties for the Run-1 data set of the Fermilab Muon g-2 Experiment. Two corrections to the measured muon precession frequency $\omega_a^m$ are associated with well-known effects owing to the use of electrostatic quadrupole (ESQ) vertical focusing in the storage ring. An average vertically oriented motional magnetic field is felt by relativistic muons passing transversely through the radial electric field components created by the ESQ system. The correction depends on the stored momentum distribution and the tunes of the ring, which has relatively weak vertical focusing. Vertical betatron motions imply that the muons do not orbit the ring in a plane exactly orthogonal to the vertical magnetic field direction. A correction is necessary to account for an average pitch angle associated with their trajectories. A third small correction is necessary because muons that escape the ring during the storage time are slightly biased in initial spin phase compared to the parent distribution. Finally, because two high-voltage resistors in the ESQ network had longer than designed RC time constants, the vertical and horizontal centroids and envelopes of the stored muon beam drifted slightly, but coherently, during each storage ring fill. This led to the discovery of an important phase-acceptance relationship that requires a correction. The sum of the corrections to $\omega_a^m$ is 0.50 $\pm$ 0.09 ppm; the uncertainty is small compared to the 0.43 ppm statistical precision of $\omega_a^m$., Comment: 35 pages, 29 figures. Accepted by Phys. Rev. Accel. Beams
Published: 2021
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7. Extraction of beam-spin asymmetries from the hard exclusive π+ channel off protons in a wide range of kinematics

Author: Y. G. Sharabian, K. Tezgin, S. E. Kuhn, M. Hattawy, S. Adhikari, M. Khachatryan, M. J. Amaryan, N. Tyler, P. Lenisa, C. Dilks, J. A. Tan, C. W. Kim, H. Avakian, B. McKinnon, Maxime Defurne, Laura Clark, K. A. Griffioen, Chaden Djalali, D. Bulumulla, T. Mineeva, L. Guo, G. Angelini, D. I. Glazier, B. S. Ishkhanov, S. Strauch, Aditya R. Khanal, F. X. Girod, T. B. Hayward, M. Guidal, D. P. Watts, K. L. Giovanetti, P. L. Cole, E. L. Isupov, E. Golovatch, G. Asryan, L. Lanza, R. De Vita, Alessandro Rizzo, Z. W. Zhao, V. Crede, R. Dupre, H. Voskanyan, Andrea Bianconi, N. Markov, Brian Raue, Y. Ghandilyan, S. Boiarinov, A. D'Angelo, M. Mirazita, M. Ehrhart, W. Phelps, W. J. Briscoe, A. Filippi, M. Holtrop, Victor Mokeev, U. Shrestha, L. El Fassi, H. Atac, P. Nadel-Turonski, M. Khandaker, Luciano Pappalardo, P. Eugenio, J. W. Price, O. Pogorelko, I. J. D. MacGregor, T. Chetry, M. Osipenko, J. Rowley, M. Ripani, Fatiha Benmokhtar, H. Hakobyan, O. Soto, M. Battaglieri, S. Diehl, Paolo Rossi, K. Park, Michael Paolone, A. Celentano, R. W. Gothe, D. Heddle, F. Bossu, D. G. Ireland, Hovanes Egiyan, C. Munoz Camacho, W. Kim, Axel Schmidt, G. Niculescu, P. Stoler, Volker D. Burkert, M. Contalbrigo, A. S. Biselli, M. Ungaro, I. I. Strakovsky, K. Hicks, A. Deur, Nicholas M. Harrison, Gerard Gilfoyle, D. Marchand, V. Mascagna, Eugene Pasyuk, W. K. Brooks, D. G. Jenkins, S. Joosten, L. Marsicano, V. P. Kubarovsky, K. P. Adhikari, M. Leali, D. Riser, Z. E. Meziani, Y. Prok, F. Sabatié, I. Bedlinskiy, P. Kroll, K. Joo, Dustin Keller, Michael Wood, A. Kim, K. Livingston, Jie Zhang, H. S. Jo, C. Salgado, A. El Alaoui, Y. Ilieva, P. Chatagnon, Nicholas Zachariou, J. C. Carvajal, K. Semenov-Tian-Shansky, N. Dashyan, E. Voutier, L. Venturelli, L. Barion, R. A. Schumacher, G. Ciullo, D. S. Carman, Nikos Sparveris, X. Wei, T. A. Forest, S. Stepanyan, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and CLAS
Subjects: Particle physics, generalized parton distribution, Partons, Nucleons, Compton Scattering, media_common.quotation_subject, General Physics and Astronomy, parton: distribution function, Socio-culturale, Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Resonance (particle physics), Asymmetry, High Energy Physics - Experiment, Pion, PE2_2, PE2_1, CLAS, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], 010306 general physics, Nuclear Experiment, PE2_3, Spin-½, media_common, Physics, Settore FIS/04, electroproduction, moment, Moment (mathematics), distribution amplitude, High Energy Physics - Phenomenology, Amplitude, kinematics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Elementary Particles and Fields, High Energy Physics::Experiment, Center of mass, asymmetry, experimental results
Abstract: We have measured beam-spin asymmetries to extract the \ud sin\ud ϕ\ud moment \ud A\ud sin\ud ϕ\ud L\ud U\ud from the hard exclusive \ud →\ud e\ud p\ud →\ud e\ud ′\ud n\ud π\ud +\ud reaction above the resonance region, for the first time with nearly full coverage from forward to backward angles in the center of mass. The \ud A\ud sin\ud ϕ\ud L\ud U\ud moment has been measured up to \ud 6.6\ud \ud \ud GeV\ud 2\ud in \ud −\ud t\ud , covering the kinematic regimes of generalized parton distributions (GPD) and baryon-to-meson transition distribution amplitudes (TDA) at the same time. The experimental results in very forward kinematics demonstrate the sensitivity to chiral-odd and chiral-even GPDs. In very backward kinematics where the TDA framework is applicable, we found \ud A\ud sin\ud ϕ\ud L\ud U\ud to be negative, while a sign change was observed near 90° in the center of mass. The unique results presented in this Letter will provide critical constraints to establish reaction mechanisms that can help to further develop the GPD and TDA frameworks.
Published: 2020

8. The CLAS12 Forward Tagger

Author: V. Vigo, E. Pasyuk, F. Cipro, A. Ciarma, D. Sokhan, R. Behary, G. Charles, T. Bey, Y. Mouden, A. Filippi, K. L. Giovanetti, T. Lemon, Q. Bertrand, F. Sabatié, A. Manco, H.S. Mann, A. Bersani, I. Mandjavidze, A. Hoebel, David Attié, M. Vandenbroucke, S. Aune, M. Garçon, R. Cereseto, G. Christiaens, E. Delagnes, D. P. Watts, R. Miller, F. Georges, N. Grouas, A. Casale, C. Salgado, C. Rossi, G. Ottonello, T. Lerch, P. Contrepois, A. Trovato, Paolo Musico, L. Zana, F. Parodi, S. M. Hughes, S. Fegan, Fatiha Benmokhtar, J. Ball, J. A. Fleming, P. Campero Rojas, Alessandro Rizzo, P. Black, M. Leffel, M. Riallot, M. Battaglieri, Andrea Celentano, G. Miní, S. Procureur, M. Cook, P. Baron, R. Puppo, O. Meunier, R. Granelli, D. Besin, L. Lanza, M. Osipenko, M. Defurne, P. Pollovio, D. I. Glazier, R. De Vita, F. Bossu, M. Ripani, K. Livingston, C. Lahonde, Nicholas Zachariou, A. Acker, M. Taiuti, P. Bonneau, K. Hicks, C. Wiggins, M. Boyer, G. D. Smith, R. Boudouin, E. Virique, E. Fanchini, F. Pratolongo, A. D'Angelo, I. Stankovic, M. Bashkanov, B. McKinnon, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay
Subjects: tungsten: oxygen, Photon, Physics::Instrumentation and Detectors, Low-Q2 electron scattering, Electron, 01 natural sciences, photon: particle identification, MicroMegas, Instrumentation, Low-Q, Physics, forward spectrometer, PbWO4, Settore FIS/04, MicroMegas detector, PbWO 4, electron scattering, Low-Q 2 electron scattering, performance, Nuclear and High Energy Physics, PbWO, Gas tracking detector, SiPM, Hodoscope, Silicon photomultiplier, Optics, Electromagnetic calorimeter, Hadron spectroscopy, APD, 2, 4, Plastic scintillator, WLS fibers, 0103 physical sciences, scintillation counter: hodoscope, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Low-Q(2) electron scattering, 010306 general physics, detector: design, activity report, Scintillation, lead, Spectrometer, electron: particle identification, 010308 nuclear & particles physics, business.industry, calorimeter: electromagnetic, business
Abstract: This document presents the technical layout and the performance of the CLAS12 Forward Tagger (FT). The FT, composed of an electromagnetic calorimeter based on PbWO4 crystals (FT-Cal), a scintillation hodoscope (FT-Hodo), and several layers of Micromegas trackers (FT-Trk), has been designed to detect electrons and photons scattered at polar angles from 2 ∘ to 5 ∘ and to meet the physics goals of the hadron spectroscopy program and other experiments running with the CLAS12 spectrometer in Hall B.
Published: 2020

9. The CLAS12 Spectrometer at Jefferson Laboratory

Author: C. W. Kim, H. Avakian, D. Protopopescu, D. Heddle, M. Contalbrigo, M. L. Kabir, H. Voskanyan, E. Voutier, T. Chetry, M. Zarecky, J. Poudel, I. Illari, B. A. Clary, M. Osipenko, D. Insley, D. P. Watts, I. Bedlinskiy, Michael Paolone, V. Sergeyeva, D. Kashy, M. Khachatryan, F. Hauenstein, V. Mascagna, Nikolaos Sparveris, F. Bossu, D. Marchand, W. Kim, G. Niculescu, P. Bonneau, G. Charles, P. Hemler, Ruben J. Fair, P. Moran, Dustin Keller, C. Ayerbe Gayoso, Nicholas Zachariou, M. Ungaro, C. Munoz Camacho, M. J. Amaryan, G. Rosner, I. J. D. MacGregor, T. A. Forest, V. Lucherini, S. E. Kuhn, Y. Prok, M. Hattawy, S. Stepanyan, Michael Wood, K. Hafidi, M. D. Mestayer, S. Lee, M. Wiseman, F. Sabatié, R. Paremuzyan, N. Dashyan, A. Deur, K. Hicks, K. Joo, E. L. Isupov, N. A. Baltzell, R. W. Gothe, S. Christo, L. C. Smith, B. S. Ishkhanov, Latifa Elouadrhiri, V. Baturin, Nicholas M. Harrison, Gerard Gilfoyle, M. McMullen, G. E. Dodge, H. S. Jo, R. Johnston, A. Yegneswaran, K. Livingston, A. Lung, P. Stoler, M. Guidal, D. Sokhan, K. Price, Aditya R. Khanal, K. P. Adhikari, Jie Zhang, K. Bruhwel, S. Adhikari, S. Boyarinov, B. McKinnon, M. Ehrhart, M. Leali, Z. W. Zhao, S. Joosten, B. J. Roy, V. P. Kubarovsky, J. Newton, P. Chatagnon, G. V. Fedotov, D. Tilles, M.A. Antonioli, Renuka Rajput-Ghoshal, G. D. Smith, M. Holtrop, C. Cuevas, V. Gyurjyan, Probir K. Ghoshal, Yordanka Ilieva, H. Hakobyan, Alexander Schmidt, Luciano Pappalardo, Andrea Bianconi, W. J. Briscoe, M. Turisini, M. Mirazita, D. I. Glazier, M. Garçon, M. Ripani, F. X. Girod, A. Filippi, K. L. Giovanetti, R. Miller, J. Ritman, S. Diehl, R. De Vita, C. D. Keith, Y. G. Sharabian, M. Lowry, M. Defurne, E. Pasyuk, P. Naidoo, J. Hogan, N. Markov, Or Hen, C. Salgado, M. Taylor, G. Young, S. Strauch, Larry Weinstein, H. Atac, Chaden Djalali, A. Hobart, A. Kim, Z. E. Meziani, S. Schadmand, U. Shrestha, T. Ewing, T. Mineeva, O. Pogorelko, S. Nanda, L. Barion, G. Angelini, J. Rowley, P. Rossi, M. Leffel, William Brooks, I. Mandjavidze, L. Venturelli, Iu. Skorodumina, Y. Gotra, C. Mealer, J. W. Price, S. Aune, C. Wiggins, D. G. Ireland, G. Gavalian, G. Jacobs, V. Crede, Volker D. Burkert, A. S. Biselli, O. Pastor, Victor Mokeev, E.P. Segarra, Ross Milner, N. Tyler, J. A. Tan, E. Golovatch, R. Dupre, W. Phelps, Andrea Celentano, S. Procureur, M. Cook, G. Ciullo, M. Battaglieri, D. S. Carman, B. Raydo, A. Rizzo, X. Wei, R. Cruz-Torres, S. Niccolai, K. A. Griffioen, B. Eng, A. Movsisyan, P. L. Cole, L. Lanza, G. Christiaens, A. D'Angelo, T. Kageya, L. El Fassi, P. Lenisa, V. Ziegler, C. Hanretty, D. Anderson, T. B. Hayward, Brian Raue, Fatiha Benmokhtar, O. Soto, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics::Instrumentation and Detectors, data acquisition, magnet: solenoid, superconductivity: torus, Solenoid, 01 natural sciences, Particle identification, Luminosity, momentum resolution, electron: beam, Nuclear Experiment, Instrumentation, QC, Physics, Luminosity (scattering theory), Settore FIS/04, Detector, Magnetic spectrometer, magnet: torus, performance, Nuclear and High Energy Physics, Meson, vertex detector, nucleon: interaction, CLAS12, Electromagnetic physics, Large acceptance, Socio-culturale, fabrication, beam: energy, Nuclear physics, PE2_1, CLAS, 0103 physical sciences, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010306 general physics, PE2_3, scintillation counter, Cherenkov radiation, detector: design, activity report, Spectrometer, 010308 nuclear & particles physics, nucleus, CLAS12, Electromagnetic physics, Large acceptance, Luminosity, Magnetic spectrometer, magnet: superconductivity, magnetic spectrometer, electromagnetic physics, large acceptance, luminosity, neutral particle, Automatic Keywords, calorimeter: electromagnetic, Cherenkov counter, spectrometer, particle identification, Beam (structure)
Abstract: International audience; The CEBAF Large Acceptance Spectrometer for operation at 12 GeV beam energy (CLAS12) in Hall B at Jefferson Laboratory is used to study electro-induced nuclear and hadronic reactions. This spectrometer provides efficient detection of charged and neutral particles over a large fraction of the full solid angle. CLAS12 has been part of the energy-doubling project of Jefferson Lab’s Continuous Electron Beam Accelerator Facility, funded by the United States Department of Energy. An international collaboration of 48 institutions contributed to the design and construction of detector hardware, developed the software packages for the simulation of complex event patterns, and commissioned the detector systems. CLAS12 is based on a dual-magnet system with a superconducting torus magnet that provides a largely azimuthal field distribution that covers the forward polar angle range up to 35 ∘ , and a solenoid magnet and detector covering the polar angles from 35° to 125° with full azimuthal coverage. Trajectory reconstruction in the forward direction using drift chambers and in the central direction using a vertex tracker results in momentum resolutions of < 1% and < 3%, respectively. Cherenkov counters, time-of-flight scintillators, and electromagnetic calorimeters provide good particle identification. Fast triggering and high data-acquisition rates allow operation at a luminosity of 1035 cm −2 s −1 . These capabilities are being used in a broad program to study the structure and interactions of nucleons, nuclei, and mesons, using polarized and unpolarized electron beams and targets for beam energies up to 11 GeV. This paper gives a general description of the design, construction, and performance of CLAS12.
Published: 2020

10. Semi-inclusive π0 target and beam-target asymmetries from 6 GeV electron scattering with CLAS

Author: P. Lenisa, W. Kim, R. Dupre, M. Battaglieri, G. Niculescu, G. Rosner, K. Livingston, M. Hattawy, Friedrich Klein, Y. Ghandilyan, A. Filippi, X. Wei, Brian Raue, M. Khandaker, M. J. Amaryan, V. I. Mokeev, D. Heddle, K. L. Giovanetti, Larry Weinstein, G. Hollis, R. A. Schumacher, Jie Zhang, K. A. Griffioen, Dustin Keller, C. Hanretty, N. Guler, G. Khachatryan, A. Celentano, R. W. Gothe, D. P. Watts, P. Nadel-Turonski, Michael Wood, Taya Chetry, W. J. Briscoe, H. Egiyan, M. Ungaro, Laura Clark, L. Lanza, S. Bültmann, M. E. McCracken, Sergey Kuleshov, K. P. Adhikari, T. A. Forest, C. Carlin, H. Avakian, F. X. Girod, S. Pisano, B. S. Ishkhanov, Sylvester Joosten, P. Eugenio, F. Cao, P. Bosted, P. Rossi, S. Strauch, D. Adikaram, E. De Sanctis, M. Guidal, M. Taiuti, J. Brock, C. Munoz Camacho, K. Joo, H. Hakobyan, D. Protopopescu, G. D. Smith, M. Holtrop, W. Phelps, V. Crede, C. Salgado, D. I. Sober, M. Garçon, J. Pierce, E. Voutier, S. Adhikari, B. McKinnon, Avraham Klein, R. A. Montgomery, C. Djalali, H. Voskanyan, Maxime Defurne, I. Bedlinskiy, L. Colaneri, O. Cortes, M. Mirazita, E. Phelps, H. Y. Lu, E. L. Isupov, E. Pasyuk, V. Batourine, R. De Vita, A. El Alaoui, S. Boiarinov, Nicholas Zachariou, A. D'Angelo, R. Paremuzyan, S. Anefalos Pereira, Nicholas M. Harrison, Gerard Gilfoyle, A. Kim, D. Sokhan, N. Markov, N. A. Baltzell, L. El Fassi, J. W. Price, I. Niculescu, V. P. Kubarovsky, Z. W. Zhao, K. Hicks, D. Riser, C. D. Keith, A. I. Ostrovidov, L. Guo, Alessandro Rizzo, O. Pogorelko, S. M. Hughes, K. Park, G. Ddoge, D. G. Ireland, I. Stankovic, T. Mineeva, H. Jiang, R. G. Fersch, Volker D. Burkert, A. S. Biselli, William Brooks, P. L. Cole, S. Koirala, A. Fradi, M. Osipenko, M. Contalbrigo, D. G. Jenkins, Iu. Skorodumina, Z. Akbar, G. Charles, A. Simonyan, F. Sabatié, N. K. Walford, S. S. Jawalkar, I. J. D. MacGregor, W. Gohn, E. Golovatch, A. Deur, L. A. Net, Latifa Elouadrhiri, C. A. Meyer, Y. G. Sharabian, G. V. Fedotov, N. Dashyan, S. E. Kuhn, Yordanka Ilieva, J. A. Fleming, Martin K. Mayer, M. Khachatryan, S. Fegan, C. Gleason, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, Nikos Sparveris, S. Niccolai, A. Movsisyan, M. Ripani, E. Seder, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), CLAS, and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
Subjects: Single spin asymmetries, Hadron, fragmentation function, 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, transverse momentum: momentum spectrum, Collins, hadron: production, Nuclear Experiment, Spin-½, Physics, deep inelastic scattering: semi-inclusive reaction, suppression, Collins fragmentation, hadron: energy, lcsh:QC1-999, Double spin asymmetries, Semi-inclusive deep-inelastic scattering, Transverse momentum distributions, High Energy Physics - Phenomenology, transverse, electron: scattering, cryogenics, spin: asymmetry, Jefferson Lab, Nuclear and High Energy Physics, pi: momentum, Quark, Socio-culturale, quark gluon: correlation, lepton: scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], quark, pi: electroproduction, Nuclear physics, Pion, target: spin, deep inelastic scattering, CLAS, 0103 physical sciences, 010306 general physics, 010308 nuclear & particles physics, Scattering, High Energy Physics::Phenomenology, Deep inelastic scattering, Gluon, Automatic Keywords, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics::Experiment, higher-dimensional, lcsh:Physics, experimental results, Lepton
Abstract: We present precision measurements of the target and beam-target spin asymmetries from neutral pion electroproduction in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We scattered 6-GeV, longitudinally polarized electrons off longitudinally polarized protons in a cryogenic $^{14}$NH$_3$ target, and extracted double and single target spin asymmetries for $ep\rightarrow e^\prime\pi^0X$ in multidimensional bins in four-momentum transfer ($1.0, Comment: 18 preprint pages, 3 figures
Published: 2018

11. Photon beam asymmetry Σ in the reaction γ→p→pω for E= 1.152 to 1.876 GeV

Author: G. Khachatryan, W. Kim, M. Battaglieri, N. K. Walford, G. Niculescu, L. Lanza, Michael Paolone, M. Bashkanov, S. Adhikari, H. Avakian, F. X. Girod, W. J. Briscoe, Laura Clark, B. McKinnon, P. Lenisa, T. Cao, M. Ungaro, I. J. D. MacGregor, F. Sabatié, I. I. Strakovsky, H. Voskanyan, A. Kim, E. De Sanctis, V. A. Nikonov, A. Deur, E. Pasyuk, J. W. Price, N. Dashyan, C. Gleason, G. Rosner, K. Hicks, V. Mokeev, P. Nadel-Turonski, V. Batourine, I. Bedlinskiy, D. I. Sober, S. Strauch, V. Crede, William Brooks, Dustin Keller, M. Defurne, Y. Ghandilyan, D. P. Watts, Barry Ritchie, Brian Raue, Alessandro Rizzo, C. Hanretty, H. Egiyan, E. Golovatch, R. Dupre, R. A. Montgomery, A. Celentano, R. W. Gothe, M. Khachatryan, Sylvester Joosten, B. S. Ishkhanov, G. Charles, Michael Wood, J. Ball, K. Hafidi, W. Phelps, H. S. Jo, A. V. Sarantsev, G. Ciullo, Y. Prok, D. I. Glazier, D. S. Carman, A. Simonyan, O. Cortes, N. A. Baltzell, C. Munoz Camacho, Nikos Sparveris, F. J. Klein, M. Ripani, M. Contalbrigo, Z. E. Meziani, E. L. Isupov, S. Niccolai, D. G. Jenkins, M. Osipenko, K. A. Griffioen, R. Paremuzyan, Eberhard Klempt, S. Boiarinov, N. Markov, V. P. Kubarovsky, A. Movsisyan, R. De Vita, Nicholas M. Harrison, O. Pogorelko, Gerard Gilfoyle, J. Zhang, S. M. Hughes, X. Wei, S. Pisano, D. Sokhan, I. Stankovic, A. V. Anisovich, C. A. Meyer, Z. Akbar, G. V. Fedotov, I. Niculescu, C. Salgado, P. L. Cole, A. I. Ostrovidov, K. Park, R. A. Schumacher, D. G. Ireland, H. Jiang, H. Hakobyan, S. Anefalos Pereira, Volker D. Burkert, A. S. Biselli, L. El Fassi, K. P. Adhikari, S. Stepanyan, E. Munevar, L. A. Net, Avraham Klein, Y. G. Sharabian, J. A. Fleming, Iu. Skorodumina, D. Heddle, G. Hollis, P. Eugenio, M. Taiuti, P. Collins, S. Procureur, K. L. Giovanetti, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, A. Filippi, M. Khandaker, K. Livingston, M. Hattawy, D. Protopopescu, Z. W. Zhao, E. Voutier, Chaden Djalali, Michael Dugger, T. Mineeva, F. Cao, D. Adikaram, M. Guidal, G. D. Smith, M. Holtrop, Taya Chetry, and Sergey Kuleshov
Subjects: Physics, Nuclear and High Energy Physics, Photon, Meson, Proton, 010308 nuclear & particles physics, Partial wave analysis, Bremsstrahlung, Photon energy, 01 natural sciences, Nuclear physics, Pomeron, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: Photon beam asymmetry Σ measurements for ω photoproduction in the reaction γ → p → ω p are reported for photon energies from 1.152 to 1.876 GeV. Data were taken using a linearly-polarized tagged photon beam, a cryogenic hydrogen target, and the CLAS spectrometer in Hall B at Jefferson Lab. The measurements obtained markedly increase the size of the database for this observable, extend coverage to higher energies, and resolve discrepancies in previously published data. Comparisons of these new results with predictions from a chiral-quark-based model and from a dynamical coupled-channels model indicate the importance of interferences between t-channel meson exchange and s- and u-channel contributions, underscoring sensitivity to the nucleon resonances included in those descriptions. Comparisons with the Bonn–Gatchina partial-wave analysis indicate the Σ data reported here help to fix the magnitudes of the interference terms between the leading amplitudes in that calculation (Pomeron exchange and the resonant portion of the J P = 3 / 2 + partial wave), as well as the resonant portions of the smaller partial waves with J P = 1 / 2 − , 3 / 2 − , and 5 / 2 + .
Published: 2017

12. First results on nucleon resonance photocouplings from the γp → π+π−p reaction

Author: I. Bedlinskiy, J. Ball, F. Cao, E. De Sanctis, M. Guidal, R. Paremuzyan, N. Markov, Y. G. Sharabian, D. I. Sober, Maxime Defurne, D. I. Glazier, I. J. D. MacGregor, R. De Vita, P. Eugenio, I. I. Strakovsky, D. Protopopescu, G. D. Smith, M. Holtrop, Z. W. Zhao, Nicholas M. Harrison, Gerard Gilfoyle, M. Taiuti, E. Voutier, A. Deur, M. Contalbrigo, M. Khachatryan, D. Sokhan, Latifa Elouadrhiri, M. L. Kabir, M. J. Amaryan, G. Ciullo, C. A. Meyer, M. Khandaker, P. Chatagnon, Y. Prok, D. S. Carman, G. V. Fedotov, Z. Akbar, F. X. Girod, Sandra K. Johnston, K. Livingston, M. Hattawy, Nikos Sparveris, K. A. Griffioen, E. Golovatch, R. Dupre, A. I. Ostrovidov, K. Park, Jie Zhang, S. Niccolai, Hovanes Egiyan, Taya Chetry, C. Munoz Camacho, A. Movsisyan, D. G. Ireland, V. Crede, F. Sabatié, Volker D. Burkert, A. S. Biselli, P. Lenisa, M. Bashkanov, S. Adhikari, B. McKinnon, K. L. Giovanetti, S. Strauch, L. Lanza, J. W. Price, V. I. Mokeev, M. Ripani, R. A. Montgomery, D. Marchand, X. Wei, D. Heddle, A. El Alaoui, Y. Ilieva, M. Battaglieri, B. A. Clary, Nicholas Zachariou, Friedrich Klein, Iu. Skorodumina, H. Hakobyan, Michael Paolone, D. G. Jenkins, N. Dashyan, S. Diehl, C. Salgado, H. S. Jo, A. Filippi, Laura Clark, L. Barion, E. L. Isupov, Michael Dugger, S. Boiarinov, R. A. Schumacher, Avraham Klein, P. Nadel-Turonski, M. Ungaro, K. Joo, N. Tyler, C. Djalali, J. A. Tan, Dustin Keller, B. S. Ishkhanov, Michael Wood, K. Hafidi, H. Avakian, H. Voskanyan, E. Pasyuk, V. P. Kubarovsky, D. Riser, O. Pogorelko, G. Khachatryan, W. J. Briscoe, G. Rosner, Y. Ghandilyan, K. Hicks, L. Guo, Alessandro Rizzo, R. G. Fersch, P. L. Cole, A. D'Angelo, L. El Fassi, M. Osipenko, Rong Wang, M. Ehrhart, W. Kim, G. Niculescu, A. Celentano, and R. W. Gothe
Subjects: Nuclear and High Energy Physics, Meson, Nuclear Theory, Hadron, Two pion photoproduction, Socio-culturale, Elementary particle, 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Particle decay, Pion, 0103 physical sciences, Invariant mass, Resonance photocouplings, Nuclear Experiment, 010306 general physics, Physics, 010308 nuclear & particles physics, Resonance, lcsh:QC1-999, Baryon state, High Energy Physics::Experiment, Nucleon, lcsh:Physics
Abstract: We report the first experimental measurements of the nine 1-fold differential cross sections for the γp→π+π−p reaction, obtained with the CLAS detector at Jefferson Laboratory. The measurements cover the invariant mass range of the final state hadrons from 1.6 GeV Δ(1620)1/2−, Δ(1700)3/2−, N(1720)3/2+, and Δ(1905)5/2+ resonances, which have dominant decays into the ππN final states rather than the more extensively studied single meson decay channels.
Published: 2019

13. Exploring the Structure of the Bound Proton with Deeply Virtual Compton Scattering

Author: A. El Alaoui, Alessandro Rizzo, C. Ayerbe Gayoso, M. Khandaker, R. Paremuzyan, Nicholas Zachariou, O. Soto, Andrea Celentano, Nicholas M. Harrison, Gerard Gilfoyle, D. P. Watts, S. Fegan, D. Sokhan, V. Crede, K. Livingston, M. Garçon, Sandra K. Johnston, R. A. Montgomery, Jie Zhang, F. X. Girod, M. Battaglieri, M. Contalbrigo, G. Gavalian, E. Golovatch, S. Strauch, Aditya R. Khanal, S. Niccolai, A. Filippi, M. Ripani, R. Dupre, N A Baltzell, K. L. Giovanetti, A. D'Angelo, E. L. Isupov, G. Khachatryan, Dustin Keller, Larry Weinstein, P. Lenisa, Yordanka Ilieva, M. Defurne, N. Markov, Chaden Djalali, Michael Wood, Laura Clark, E. De Sanctis, F. Sabatié, D. Heddle, K. A. Griffioen, T. Mineeva, L. Barion, K. Hafidi, J. Poudel, Taya Chetry, C. Munoz Camacho, P. L. Cole, Iu. Skorodumina, G. Angelini, P. Rossi, T. B. Hayward, D. Protopopescu, Z. W. Zhao, B. McKinnon, F. Hauenstein, Friedrich Klein, L. Lanza, B. Torayev, A Fradi, S. Diehl, C. Salgado, V. P. Kubarovsky, D. Riser, G. Ciullo, O. Pogorelko, M. Mirazita, H. Egiyan, F. Bossu, G. Rosner, P. Eugenio, Y. Prok, D. S. Carman, L. El Fassi, E. Pasyuk, M. Taiuti, C. W. Kim, Zein-Eddine Meziani, F. Cao, M. L. Kabir, S. E. Kuhn, M. Hattawy, H. Voskanyan, A. I. Ostrovidov, D. G. Jenkins, I. J. D. MacGregor, M. Guidal, Rong Wang, N. Dashyan, D. G. Ireland, M Ehrhart, A. S. Biselli, N. Gevorgyan, R. W. Gothe, M. Holtrop, I. Bedlinskiy, Luciano Pappalardo, Martin K. Mayer, A. Deur, W. Kim, M. Khachatryan, Nikolaos Sparveris, W. K. Brooks, S. Adhikari, Y. G. Sharabian, R. De Vita, D. Marchand, H. S. Jo, X. Wei, R. A. Schumacher, S. Bültmann, T. A. Forest, S. Stepanyan, Simonetta Liuti, M. Ungaro, Y. Perrin, K. Hicks, P. Chatagnon, P. Nadel-Turonski, N. Tyler, J. A. Tan, E. Voutier, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CLAS, Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)
Subjects: generalized parton distribution, Proton, EMC effect, Nuclear Theory, General Physics and Astronomy, Virtual particle, parton: distribution function, Parton, Electron, 01 natural sciences, 7. Clean energy, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Electromagnetic probes, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), Form factors, Electromagnetic probes, Nuclear Structure, Deep Virtual Compton Scattering, Quark models, Electron-ion collisions, Nuclear structure & decays, Nucleon distribution, electron: beam, Nuclear Experiment, Physics, Settore FIS/04, Form factors, nucleon, matter: effect, kinematics, Quark models, Nucleon, spin: asymmetry, accelerator, FOS: Physical sciences, Socio-culturale, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Structure, Deep Virtual Compton Scattering, Nuclear physics, PE2_2, PE2_1, deeply virtual Compton scattering, CLAS, 0103 physical sciences, structure, 010306 general physics, PE2_3, Electron-ion collisions, Nuclear Physics, Scattering, Nuclear structure &amp, Compton scattering, Automatic Keywords, Physics::Accelerator Physics, High Energy Physics::Experiment, Nucleon distribution, spectrometer, decays, experimental results, photon: virtual
Abstract: In the past two decades, deeply virtual Compton scattering of electrons has been successfully used to advance our knowledge of the partonic structure of the free proton and investigate correlations between the transverse position and the longitudinal momentum of quarks inside the nucleon. Meanwhile, the structure of bound nucleons in nuclei has been studied in inclusive deep-inelastic lepton scattering experiments off nuclear targets, showing a significant difference in longitudinal momentum distribution of quarks inside the bound nucleon, known as the EMC effect. In this work, we report the first beam spin asymmetry (BSA) measurement of exclusive deeply virtual Compton scattering (DVCS) off a proton bound in $^4$He. The data used here were accumulated using a $6$ GeV longitudinally polarized electron beam incident on a pressurized $^4$He gaseous target placed within the CLAS spectrometer in Hall-B at the Thomas Jefferson National Accelerator Facility. The azimuthal angle ($\phi$) dependence of the BSA was studied in a wide range of virtual photon and scattered proton kinematics. The $Q^2$, $x_B$, and t dependencies of the BSA on the bound proton are compared with those on the free proton. In the whole kinematical region of our measurements, the BSA on the bound proton is smaller by 20\% to 40\%, indicating possible medium modification of its partonic structure.
Published: 2019

14. Direct Observation of Proton-Neutron Short-Range Correlation Dominance in Heavy Nuclei

Author: W. Phelps, T. B. Hayward, Or Hen, Rong Wang, Friedrich Klein, P. Eugenio, M. Taiuti, M. L. Kabir, Andrea Celentano, X. Wei, J.R. Pybus, L. Guo, A. Beck, S. Niccolai, Laura Clark, A. I. Ostrovidov, G. Rosner, M. Contalbrigo, A. Denniston, D. G. Ireland, C. Hanretty, A. Hrnjic, G. Niculescu, K. A. Griffioen, G. Ciullo, G. Angelini, P. Rossi, D. S. Carman, Volker D. Burkert, A. S. Biselli, R. Cruz Torres, K. Livingston, A. Rizzo, M. Duer, Michael Paolone, N. Markov, H. S. Jo, Iu. Skorodumina, A. Movsisyan, S. Diehl, Y. Prok, E. L. Isupov, B. McKinnon, N. Tyler, M. Osipenko, R. W. Gothe, M. Khandaker, Michael Wood, J. A. Tan, V. Crede, Y. Ilieva, K. Joo, E. De Sanctis, F. Cao, B. Duran, I. Korover, R. A. Montgomery, K. Hicks, D. Heddle, I. Bedlinskiy, S. Stepanyan, H. Voskanyan, F. Hauenstein, R. A. Schumacher, M. Battaglieri, Chaden Djalali, F. X. Girod, B. Mustapha, E. Pasyuk, N. Dashyan, H. Hakobyan, A. D'Angelo, F. Sabatié, M. Holtrop, M. Mirazita, I. J. D. MacGregor, Eliahu Cohen, K. Park, A. El Alaoui, P. Nadel-Turonski, H. Egiyan, T. A. Forest, W. Kim, B. S. Ishkhanov, David M. Keller, E.P. Segarra, L. El Fassi, Aditya R. Khanal, Nicholas Zachariou, S. E. Kuhn, Eli Piasetzky, M. Ripani, S. Strauch, V. P. Kubarovsky, Taya Chetry, M. Hattawy, Nir Barnea, Axel Schmidt, J. Zhang, D. Protopopescu, P. L. Cole, Z. W. Zhao, E. Voutier, Y. G. Sharabian, A. Deur, W. K. Brooks, S. Adhikari, E. Golovatch, R. Dupre, Ronen Weiss, K. Hafidi, L. Lanza, M. Khachatryan, C. Munoz Camacho, Nikolaos Sparveris, M. Patsyuk, R. Paremuzyan, Nicholas M. Harrison, Gerard Gilfoyle, D. Sokhan, A. Filippi, K. L. Giovanetti, Larry Weinstein, X. Zheng, R. De Vita, S. Mey-Tal Beck, B. Schmookler, D. Marchand, M. Ungaro, G. Laskaris, S. Boiarinov, O. Pogorelko, O. Cortes, Victor Mokeev, P. Lenisa, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CLAS, and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Triple coincidence, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], General Physics and Astronomy, Socio-culturale, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear matter in neutron stars, Correlation, Nuclear Theory (nucl-th), 0103 physical sciences, Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Nuclear theory, Asymmetric nuclear matter,Lepton induced nuclear reactions, Nuclear matter in neutron stars, Nucleon distribution, Nucleon-nucleon interactions, Nuclear Physics, Physics, Settore FIS/04, Direct observation, Formalism (philosophy of mathematics), Lepton induced nuclear reactions, Nucleon-nucleon interactions, Nucleon distribution, Atomic physics, Nucleon, Asymmetric nuclear matter
Abstract: We measured the triple coincidence A(e,e'np) and A(e,e'pp) reactions on carbon, aluminum, iron, and lead targets at Q2 > 1.5 (GeV/c)2, xB > 1.1 and missing momentum > 400 MeV/c. This was the first direct measurement of both proton-proton (pp) and neutron-proton (np) short-range correlated (SRC) pair knockout from heavy asymmetric nuclei. For all measured nuclei, the average proton-proton (pp) to neutron-proton (np) reduced cross-section ratio is about 6%, in agreement with previous indirect measurements. Correcting for Single-Charge Exchange effects decreased the SRC pairs ratio to ~ 3%, which is lower than previous results. Comparisons to theoretical Generalized Contact Formalism (GCF) cross-section calculations show good agreement using both phenomenological and chiral nucleon-nucleon potentials, favoring a lower pp to np pair ratio. The ability of the GCF calculation to describe the experimental data using either phenomenological or chiral potentials suggests possible reduction of scale- and scheme-dependence in cross section ratios. Our results also support the high-resolution description of high-momentum states being predominantly due to nucleons in SRC pairs., Accepted for publication in PRL. 9 pages, 3 figures, 3 tables and supplementary materials
Published: 2019

15. Beam-target helicity asymmetry E in K0Λ and K0Σ0 photoproduction on the neutron

Author: P. Lenisa, M. Ungaro, D. G. Ireland, C. A. Meyer, R. Dupre, V. Crede, C.D. Bass, V. A. Nikonov, M. Battaglieri, P. Chatagnon, G. V. Fedotov, R. A. Montgomery, Ron L. Workman, R. Paremuzyan, R. A. Schumacher, C. S. Whisnant, K. P. Adhikari, A. Fradi, M. Osipenko, D. G. Jenkins, Nicholas M. Harrison, N. Markov, Martin K. Mayer, K. A. Griffioen, I. Zonta, I. J. D. MacGregor, A. Kim, H. Hakobyan, M. Khachatryan, D. Sokhan, H. S. Jo, Tim O'Connell, D. Marchand, S. Diehl, M. Bashkanov, B. McKinnon, A. I. Ostrovidov, K. Park, V. Mokeev, G. Khachatryan, L. Lanza, Eberhard Klempt, P. Collins, S. Niccolai, F. X. Girod, M. Contalbrigo, Sandra K. Johnston, P. Eugenio, T. Chetry, Volker D. Burkert, A. S. Biselli, Pawel Nadel-Turonski, M. Mirazita, J. Zhang, Rong Wang, J. W. Price, Alessandro Rizzo, S. Strauch, Iu. Skorodumina, C. Hanretty, George Davey Smith, M. Taiuti, C. Djalali, J. A. Tan, E. Golovatch, Y. G. Sharabian, M. Lowry, G. Charles, K. L. Giovanetti, I. Bedlinskiy, M. Rehfuss, K. Hicks, S. Adhikari, M. L. Kabir, M. Ehrhart, F. Sabatié, Andreas Klein, V. Laine, F. Cao, D. Adikaram, M. Guidal, W. Kim, Larry Weinstein, Z. Akbar, G. Rosner, P. Peng, C. Munoz Camacho, M. H. Wood, M. Hattawy, G. Niculescu, J. A. Fleming, I. I. Strakovsky, M. Holtrop, A. Filippi, A. D'Angelo, M. Ripani, Y. Ghandilyan, Carlos A. Salgado, B. A. Clary, A. M. Sandorfi, B. S. Ishkhanov, M. Khandaker, D. I. Sober, A. Deur, Hong Lu, Michael Paolone, D. Ho, S. Fegan, A. Celentano, R. W. Gothe, D. Heddle, Maxime Defurne, E. L. Isupov, W. Gohn, S. Boiarinov, R. De Vita, T. Kageya, L. El Fassi, N. K. Walford, R. G. Fersch, Frank Klein, P. L. Cole, Z. W. Zhao, Dustin Keller, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, Nikos Sparveris, X. Wei, K. Hafidi, E. Voutier, A. Movsisyan, Yordanka Ilieva, L. Barion, V. P. Kubarovsky, D. Riser, A. El Alaoui, Nicholas Zachariou, O. Pogorelko, K. Livingston, H. Voskanyan, D. Protopopescu, W. J. Briscoe, E. Pasyuk, D. P. Watts, H. Egiyan, A. V. Sarantsev, and S. Chandavar
Subjects: Physics, Strange quark, 010308 nuclear & particles physics, media_common.quotation_subject, Nuclear Theory, Quark model, Hyperon, 01 natural sciences, Helicity, Asymmetry, Pseudoscalar meson, Nuclear physics, 13. Climate action, Isospin, 0103 physical sciences, Neutron, Nuclear Experiment, 010306 general physics, media_common
Abstract: We report the first measurements of the E beam-target helicity asymmetry for the γn→K0Λ and K0Σ0 channels in the energy range 1.70≤W≤2.34 GeV. The CLAS system at Jefferson Lab uses a circularly polarized photon beam and a target consisting of longitudinally polarized solid molecular hydrogen deuteride with low background contamination for the measurements. The multivariate analysis method boosted decision trees is used to isolate the reactions of interest. Comparisons with predictions from the KaonMAID, SAID, and Bonn-Gatchina models are presented. These results will help separate the isospin I=0 and I=1 photocoupling transition amplitudes in pseudoscalar meson photoproduction.
Published: 2018

16. Photoproduction of K+K− meson pairs on the proton

Author: G. Ricco, R. A. Schumacher, K. Mikhailov, L. Bibrzycki, P. Stoler, A. D'Angelo, K. Hicks, H. Hakobyan, Ashot Gasparian, L. Gan, V. Mokeev, A.V. Stavinsky, K. Livingston, D. S. Dale, S. Anefalos Pereira, A. V. Vlassov, D. J. Tedeschi, V. V. Mochalov, K. A. Griffioen, S. Fegan, E. Clinton, Michael Wood, N. Hassall, M. Bellis, K. Hafidi, Michael Vineyard, R. De Vita, S. Stepanyan, C. Bookwalter, P. Nadel-Turonski, M. Kossov, Avraham Klein, T. Mineeva, V. Drozdov, S. Strauch, V. Kuznetsov, Friedrich Klein, D. P. Watts, E. L. Isupov, E. Munevar, H. Egiyan, I. Nakagawa, I. Bedlinskiy, Brian Raue, W. J. Briscoe, Michael L. Williams, A. Kubarovsky, W. Gohn, E. Wolin, Lorenzo Zana, M. Y. Gabrielyan, C. E. Hyde, O. Glamazdin, M. R. Niroula, Z. W. Zhao, S. Niccolai, Y. Prok, D. S. Carman, M. Battaglieri, Barry Ritchie, N. Pivnyuk, I. I. Strakovsky, D. Protopopescu, C. Salgado, E. De Sanctis, M. Garçon, S. Pozdniakov, A. Deur, G. E. Dodge, Martin K. Mayer, G. Rosner, H. Y. Lu, Kei Moriya, C. A. Meyer, M. Osipenko, N. Dashyan, D. I. Sober, F. X. Girod, E. Pasyuk, G. V. Fedotov, S. Tkachenko, Adam P. Szczepaniak, M. S. Saini, I. Niculescu, P. Eugenio, H. Baghdasaryan, K. P. Adhikari, D. P. Weygand, E. Golovatch, M. Taiuti, J. T. Goetz, D. Schott, J. W. Price, C. Djalali, F. Sabatié, V. P. Kubarovsky, O. Pogorelko, W. Kim, P. Collins, M. Anghinolfi, Leonard Lesniak, H. Seraydaryan, J. Zhang, P. Khetarpal, Y. G. Sharabian, C. S. Nepali, M. Ripani, V. Crede, C. Hanretty, J. R. Johnstone, L. Guo, M. Ungaro, S. Park, P. Rossi, K. Joo, M. Guidal, M. Holtrop, A. Daniel, A. I. Ostrovidov, K. Park, Sergey Kuleshov, D. G. Ireland, S. S. Stepanyan, Mark W. Paris, B. Zhao, Volker D. Burkert, A. S. Biselli, S. Dhamija, R. W. Gothe, A. Fradi, M. J. Amaryan, J. Goett, B. McKinnon, D. Branford, S. Pisano, M. Mirazita, S. L. Careccia, J. M. Laget, K. L. Giovanetti, Larry Weinstein, D. Keller, Gerard Gilfoyle, M. Khandaker, M. E. McCracken, Y. Ilieva, D. Sokhan, D. Doughty, A. Teymurazyan, and P. L. Cole
Subjects: Physics, Particle physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Hadron, Elementary particle, 01 natural sciences, 7. Clean energy, Particle decay, Pion, 0103 physical sciences, High Energy Physics::Experiment, Production (computer science), Nuclear Experiment, 010306 general physics, Nucleon
Abstract: The exclusive reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ was studied in the photon energy range 3.0--3.8 GeV and the momentum transfer range $0.4l\ensuremath{-}tl1.0\text{ }\text{ }{\mathrm{GeV}}^{2}$. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range, the integrated luminosity was about $20\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$. The reaction was isolated by detecting the ${\ensuremath{\pi}}^{+}$ and proton in CLAS, and reconstructing the ${\ensuremath{\pi}}^{\ensuremath{-}}$ via the missing-mass technique. Moments of the di-pion decay angular distributions were derived from the experimental data. Differential cross sections for the $S$, $P$, and $D$-waves, in the ${M}_{{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}}$ mass range 0.4--1.4 GeV, were derived performing a partial wave expansion of the extracted moments. Beside the dominant contribution of the $\ensuremath{\rho}(770)$ meson in the $P$-wave, evidence for the ${f}_{0}(980)$ and the ${f}_{2}(1270)$ mesons was found in the $S$ and $D$-waves, respectively. The differential production cross sections $d\ensuremath{\sigma}/dt$ for individual waves in the mass range of the above-mentioned mesons were extracted. This is the first time the ${f}_{0}(980)$ has been measured in a photoproduction experiment.
Published: 2018

17. Center of Mass Motion of Short-Range Correlated Nucleon Pairs studied via the A(e,e′pp) Reaction

Author: D. Protopopescu, Z. W. Zhao, E. Voutier, M. Duer, D. Marchand, X. Wei, Dustin Keller, P. Eugenio, I. J. D. MacGregor, G. Ciullo, M. Taiuti, C. Djalali, J. A. Tan, W. Kim, Y. Prok, F. Sabatié, L. Lanza, J. P. Ball, D. S. Carman, G. Niculescu, M. L. Kabir, P. Lenisa, S. Strauch, Michael Wood, K. Hafidi, B. A. Clary, K. Livingston, D. G. Jenkins, S. Niccolai, A. Movsisyan, Jie Zhang, Michael Paolone, D. Heddle, A. Celentano, R. W. Gothe, N. Dashyan, Maxime Defurne, H. Avakian, S. E. Kuhn, Friedrich Klein, M. Contalbrigo, A. Beck, Hovanes Egiyan, C. Munoz Camacho, M. Osipenko, M. Ungaro, Eli Piasetzky, H. Voskanyan, R. Fersch, Or Hen, Z. Akbar, L. Barion, R. De Vita, P. Nadel-Turonski, V. Crede, Alessandro Rizzo, Eliahu Cohen, E. Golovatch, R. Dupre, W. J. Briscoe, E. Pasyuk, A. El Alaoui, R. A. Montgomery, R. Paremuzyan, V. Mokeev, M. Battaglieri, M. Ripani, F. Hauenstein, B. S. Ishkhanov, Nicholas M. Harrison, Nicholas Zachariou, Rong Wang, D. Sokhan, Alexander Schmidt, D. P. Watts, S. Adhikari, K. Hicks, B. McKinnon, E. De Sanctis, S. Mey-Tal Beck, A. Kim, V. P. Kubarovsky, Y. G. Sharabian, D. Riser, A. I. Ostrovidov, A. Filippi, P. Rossi, X. Zheng, M. Ehrhart, O. Pogorelko, M. Mirazita, A. Deur, D. G. Ireland, I. Bedlinskiy, M. Khachatryan, M. Khandaker, Nikolaos Sparveris, Volker D. Burkert, A. S. Biselli, M. J. Amaryan, Sandra K. Johnston, K. L. Giovanetti, Larry Weinstein, B. Schmookler, C. A. Meyer, P. Chatagnon, G. V. Fedotov, F. Cao, I. Korover, B. Mustapha, M. Holtrop, Taya Chetry, G. Charles, E. L. Isupov, S. Boiarinov, R. Cruz Torres, H. Hakobyan, S. Diehl, F. X. Girod, J. W. Price, R. A. Schumacher, S. Stepanyan, Avraham Klein, H. S. Jo, A. D'Angelo, L. El Fassi, G. Khachatryan, G. Rosner, Y. Ghandilyan, and K. A. Griffioen
Subjects: Physics, Range (particle radiation), 010308 nuclear & particles physics, Nuclear Theory, General Physics and Astronomy, 01 natural sciences, 7. Clean energy, Momentum, medicine.anatomical_structure, Quantum state, 0103 physical sciences, medicine, Nuclear force, Center of mass, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Nucleus, Fermi Gamma-ray Space Telescope
Abstract: Short-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all nucleons with momentum greater than the Fermi momentum (k_{F}). A fundamental characteristic of SRC pairs is having large relative momenta as compared to k_{F}, and smaller center of mass (c.m.) which indicates a small separation distance between the nucleons in the pair. Determining the c.m. momentum distribution of SRC pairs is essential for understanding their formation process. We report here on the extraction of the c.m. motion of proton-proton (pp) SRC pairs in carbon and, for the first time in heavier and ansymetric nuclei: aluminum, iron, and lead, from measurements of the A(e,e^{'}pp) reaction. We find that the pair c.m. motion for these nuclei can be described by a three-dimensional Gaussian with a narrow width ranging from 140 to 170 MeV/c, approximately consistent with the sum of two mean-field nucleon momenta. Comparison with calculations appears to show that the SRC pairs are formed from mean-field nucleons in specific quantum states.
Published: 2018

18. Exclusive photoproduction of π0 up to large values of Mandelstam variables s,t, and u with CLAS

Author: S. Adhikari, S. E. Kuhn, M. Hattawy, P. Eugenio, Taya Chetry, E. Golovatch, M. Taiuti, D. Lersch, M. L. Kabir, E. De Sanctis, Carlos A. Salgado, Michael Paolone, S. Procureur, D. I. Sober, D. Protopopescu, G. V. Fedotov, A. Roy, M. Ripani, M. Khachatryan, D. P. Weygand, R. Dupre, M. Battaglieri, Maxime Defurne, M. C. Kunkel, J. Ritman, F. Cao, M. Guidal, Michael Dugger, G. Gavalian, V. P. Kubarovsky, O. Pogorelko, D. I. Glazier, G. Niculescu, P. Lenisa, A. El Alaoui, Barry Ritchie, Iu. Skorodumina, I. Balossino, D. G. Ireland, V. Crede, Frank Klein, I. Bedlinskiy, K. A. Griffioen, R. De Vita, W. Gohn, V. Mokeev, M. Holtrop, L. Elouadrhiri, Y. G. Sharabian, Andreas Klein, Nicholas Zachariou, G. Mbianda Njencheu, W. Phelps, R. A. Schumacher, Dustin Keller, I. I. Strakovsky, A. Filippi, A. Deur, C. Djalali, R. A. Montgomery, K. Hafidi, V. Batourine, H. Avakian, J. A. Tan, L. Lanza, A. D'Angelo, D. P. Watts, D. G. Jenkins, H. Voskanyan, K. Livingston, F. Sabatié, H. Egiyan, M. Khandaker, S. Niccolai, J. Zhang, S. Bültmann, W. J. Briscoe, E. Pasyuk, Alessandro Rizzo, L. El Fassi, J. W. Price, C. E. Hyde, F. X. Girod, L. Guo, M. Ungaro, T. Mineeva, R. G. Fersch, Pawel Nadel-Turonski, P. L. Cole, Z. W. Zhao, K. Hicks, Laura Clark, W. Kim, K. Joo, S. Strauch, G. Charles, B. S. Ishkhanov, O. Cortes, G. Ciullo, E. L. Isupov, J. P. Ball, Y. Prok, D. S. Carman, D. Payette, M. Osipenko, S. Boiarinov, Nikos Sparveris, X. Wei, I. J. D. MacGregor, K. P. Adhikari, A. Kim, E. Voutier, A. Movsisyan, N. Dashyan, H. Hakobyan, S. Stepanyan, L. Barion, M. J. Amaryan, K. L. Giovanetti, Larry Weinstein, G. Khachatryan, S. Schadmand, William Brooks, G. Rosner, S. Ghosh, Y. Ghandilyan, P. V. Degtyarenko, A. Celentano, R. W. Gothe, M. Contalbrigo, C. Munoz Camacho, J. Poudel, B. McKinnon, J. M. Laget, Nicholas M. Harrison, Gerard Gilfoyle, D. Sokhan, A. Fradi, N. Markov, A. I. Ostrovidov, K. Park, G. R. Goldstein, Volker D. Burkert, and A. S. Biselli
Subjects: Quark, Quantum chromodynamics, Physics, Meson, 010308 nuclear & particles physics, Perturbative QCD, Parton, Mandelstam variables, Photon energy, 01 natural sciences, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Sum rule in quantum mechanics, 010306 general physics
Abstract: Exclusive photoproduction cross sections have been measured for the process γ p → p π 0 [ e + e − ( γ ) ] with the Dalitz decay final state using tagged photon energies in the range of E γ = 1.275 – 5.425 GeV. The complete angular distribution of the final state π 0 , for the entire photon energy range up to large values of t and u , has been measured for the first time. The data obtained show that the cross section d σ / d t , at mid to large angles, decreases with energy as s − 6.89 ± 0.26 . This is in agreement with the perturbative QCD quark counting rule prediction of s − 7 . Paradoxically, the size of angular distribution of measured cross sections is greatly underestimated by the QCD-based generalized parton distribution mechanism at highest available invariant energy s = 11 GeV 2 . At the same time, the Regge-exchange-based models for π 0 photoproduction are more consistent with experimental data.
Published: 2018

19. Differential cross section for γd → ωd using CLAS at Jefferson Lab

Author: R. W. Gothe, I. J. D. MacGregor, M. Contalbrigo, K. A. Griffioen, S. Adhikari, S. Strauch, V. Crede, Taya Chetry, A. Filippi, I. I. Strakovsky, A. Deur, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, Nikos Sparveris, E. Voutier, Misak Sargsian, M. Khandaker, L. Lanza, S. Niccolai, A. El Alaoui, Y. Ilieva, N. Compton, A. Movsisyan, M. Khachatryan, E. De Sanctis, Nicholas Zachariou, I. Bedlinskiy, W. K. Brooks, B. McKinnon, E. L. Isupov, M. Battaglieri, Iu. Skorodumina, P. Eugenio, M. Osipenko, M. Taiuti, R. A. Schumacher, Laura Clark, P. Lenisa, D. I. Sober, S. Boiarinov, M. L. Kabir, G. Charles, A. Kim, K. Livingston, M. Hattawy, A. D'Angelo, E. Golovatch, D. G. Jenkins, G. D. Smith, R. Dupre, N. Markov, Jie Zhang, M. Holtrop, Friedrich Klein, K. L. Giovanetti, Andrea Celentano, S. Stepanyan, Larry Weinstein, G. V. Fedotov, R. De Vita, C. Salgado, V. Batourine, L. El Fassi, P. Nadel-Turonski, N. Dashyan, G. Gavalian, V. Mokeev, Z. W. Zhao, R. Paremuzyan, Nicholas M. Harrison, F. X. Girod, L. Barion, S. Johnston, J. W. Price, M. Ripani, B. A. Clary, Michael Paolone, Barry Ritchie, A. I. Ostrovidov, K. Park, D. G. Ireland, Volker D. Burkert, A. S. Biselli, C. Djalali, J. A. Tan, D. Sokhan, W. Kim, C. Munoz Camacho, G. Niculescu, R. G. Fersch, P. L. Cole, M. Ungaro, H. Voskanyan, B. S. Ishkhanov, E. Pasyuk, V. P. Kubarovsky, D. Riser, O. Pogorelko, I. Balossino, G. Khachatryan, Dustin Keller, W. J. Briscoe, Michael Wood, K. Hafidi, L. Guo, Alessandro Rizzo, K. Hicks, W. Phelps, G. Rosner, and Y. Ghandilyan
Subjects: Vector Meson Dominance, Nuclear and High Energy Physics, Meson, Nuclear Theory, Socio-culturale, Double scattering, Photon energy, 01 natural sciences, 7. Clean energy, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Cross section (physics), 0103 physical sciences, 010306 general physics, Nuclear Experiment, Physics, Range (particle radiation), 010308 nuclear & particles physics, Scattering, Momentum transfer, Differential cross section, Single scattering, Vector meson dominance, lcsh:QC1-999, Deuterium, High Energy Physics::Experiment, lcsh:Physics
Abstract: The cross section for coherent ω-meson photoproduction off the deuteron has been measured for the first time as a function of the momentum transfer t=(Pγ−Pω)2 and photon energy Eγ using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cross sections are measured in the energy range 1.4
Published: 2018

20. Measurement of the beam asymmetry Σ and the target asymmetry T in the photoproduction of ω mesons off the proton using CLAS at Jefferson Laboratory

Author: William Brooks, George Davey Smith, R. A. Schumacher, A. El Alaoui, S. Stepanyan, J. Pierce, H. Y. Lu, P. Eugenio, G. Gavalian, I. Denisenko, N. Dashyan, Taya Chetry, M. Taiuti, A. Filippi, A. Fradi, D. P. Watts, K. A. Griffioen, Friedrich Klein, V. Crede, M. Khandaker, D. G. Meekins, Brian Raue, A. D'Angelo, A. V. Sarantsev, Yordanka Ilieva, Nicholas Zachariou, E. Pasyuk, V. Mokeev, V. Batourine, R. Paremuzyan, R. De Vita, N. Markov, L. Lanza, G. Rosner, E. Golovatch, K. Hicks, W. Kim, Sergey Kuleshov, M. Ripani, R. A. Montgomery, F. Sabatié, S. Niccolai, Carlos A. Salgado, C. D. Keith, Pawel Nadel-Turonski, D. G. Jenkins, Eberhard Klempt, B. A. Clary, J. Brock, Alessandro Rizzo, R. Dupre, M. Battaglieri, J. Zhang, C. Djalali, J. A. Tan, L. El Fassi, J. W. Price, S. Anefalos Pereira, K. Livingston, C. Hanretty, C. Carlin, M. Guidal, L. Guo, M. Ungaro, Gerard Gilfoyle, A. I. Ostrovidov, A. V. Anisovich, K. Park, G. Charles, G. Niculescu, V. A. Nikonov, G. Ciullo, J. P. Ball, B. Torayev, Y. Prok, F. X. Girod, M. E. McCracken, D. S. Carman, D. G. Ireland, M. Holtrop, K. Joo, I. Bedlinskiy, V. P. Kubarovsky, D. Riser, M. Osipenko, Andreas Klein, Nikos Sparveris, X. Wei, T. Mineeva, D. Sokhan, O. Pogorelko, S. Procureur, W. Gohn, A. Kim, Z. E. Meziani, W. Phelps, Volker D. Burkert, M. Bashkanov, A. S. Biselli, B. S. Ishkhanov, L. Elouadrhiri, K. L. Giovanetti, I. Balossino, S. Strauch, Michael Dugger, D. I. Sober, E. Voutier, I. I. Strakovsky, A. Movsisyan, B. McKinnon, Dustin Keller, S. Park, A. Deur, K. Hafidi, Iu. Skorodumina, Sylvester Joosten, S. Fegan, G. Khachatryan, P. L. Cole, Z. W. Zhao, E. Phelps, N. Gevorgyan, D. Protopopescu, W. J. Briscoe, C. Munoz Camacho, M. H. Wood, A. Celentano, R. W. Gothe, M. Contalbrigo, Z. Akbar, N. K. Walford, I. J. D. MacGregor, S. Adhikari, M. Hattawy, Martin K. Mayer, Y. G. Sharabian, C. Gleason, Barry Ritchie, P. Roy, C. A. Meyer, G. V. Fedotov, E. L. Isupov, S. Boiarinov, K. P. Adhikari, H. Hakobyan, and P. Lenisa
Subjects: Physics, Particle physics, Proton, Meson, 010308 nuclear & particles physics, Partial wave analysis, media_common.quotation_subject, Nuclear Theory, Bremsstrahlung, Observable, 7. Clean energy, 01 natural sciences, Resonance (particle physics), Asymmetry, Baryon, Nuclear physics, 13. Climate action, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, media_common
Abstract: The photoproduction of ω mesons off the proton has been studied in the reaction γp→pω using the CEBAF Large Acceptance Spectrometer (CLAS) and the frozen-spin target in Hall B at the Thomas Jefferson National Accelerator Facility. For the first time, the target asymmetry T has been measured in photoproduction from the decay ω→π+π-π0, using a transversely polarized target with energies ranging from just above the reaction threshold up to 2.8 GeV. Significant nonzero values are observed for these asymmetries, reaching about 30-40% in the third-resonance region. New measurements for the photon-beam asymmetry Σ are also presented, which agree well with previous CLAS results and extend the world database up to 2.1 GeV. These data and additional ω photoproduction observables from CLAS were included in a partial-wave analysis within the Bonn-Gatchina framework. Significant contributions from s-channel resonance production were found in addition to t-channel exchange processes.
Published: 2018

21. Measurement of Unpolarized and Polarized Cross Sections for Deeply Virtual Compton Scattering on the Proton at Jefferson Laboratory with CLAS

Author: F. Cao, W. Phelps, M. Guidal, E. Pasyuk, N. Dashyan, P. Lenisa, Andrea Celentano, M. Holtrop, S. Procureur, W. Gohn, S. E. Kuhn, G. Charles, M. J. Amaryan, H. S. Jo, H. Y. Lu, H. Voskanyan, B. McKinnon, Iu. Skorodumina, Friedrich Klein, Z. W. Zhao, A. I. Ostrovidov, R. A. Montgomery, Y. Prok, F. Sabatié, David M. Keller, Maxime Defurne, B. Guegan, K. A. Griffioen, H. Hakobyan, P. Stoler, A. Kim, M. Mirazita, A. El Alaoui, A. Filippi, N. Markov, A. Fradi, Latifa Elouadrhiri, X. Wei, G. Rosner, Taya Chetry, C. A. Meyer, I. Balossino, N. Gevorgyan, S. Johnston, K. L. Giovanetti, E. L. Isupov, G. V. Fedotov, K. Hicks, Y. Ghandilyan, Nicholas Zachariou, P. Eugenio, G. Niculescu, V. Batourine, D. G. Ireland, Sergey Kuleshov, M. Ripani, A. Deur, L. Guo, T. Mineeva, K. P. Adhikari, J. A. Tan, M. L. Kabir, S. Niccolai, Volker D. Burkert, W. K. Brooks, D. P. Watts, B. S. Ishkhanov, S. Adhikari, A. S. Biselli, D. Heddle, M. Battaglieri, C. Gleason, M. Khachatryan, D. G. Jenkins, M. Ungaro, R. De Vita, G. Khachatryan, E. Golovatch, R. Dupre, K. Park, Y. Ilieva, Nikolaos Sparveris, L. Lanza, R. W. Gothe, W. Kim, I. Bedlinskiy, K. Livingston, C. Munoz Camacho, M. Hattawy, R. A. Schumacher, M. Osipenko, P. Rossi, W. J. Briscoe, A. D'Angelo, R. G. Fersch, V. P. Kubarovsky, P. Nadel-Turonski, D. Riser, M. Khandaker, S. Stepanyan, R. Paremuzyan, K. Hafidi, S. Bültmann, T. A. Forest, P. L. Cole, Sylvester Joosten, O. Pogorelko, S. Diehl, S. Anefalos Pereira, Avraham Klein, Nicholas M. Harrison, Gerard Gilfoyle, J. W. Price, I. J. D. MacGregor, M. Contalbrigo, Martin Wood, C. Hanretty, L. Barion, C. Salgado, M. Taiuti, J. Zhang, D. Protopopescu, Victor Mokeev, Z. Akbar, M. Garçon, E. Voutier, Y. G. Sharabian, G. Ciullo, J. P. Ball, D. S. Carman, A. Rizzo, A. Movsisyan, L. El Fassi, Zein-Eddine Meziani, M. E. McCracken, F. X. Girod, O. Cortes, S. Boiarinov, Chaden Djalali, G. D. Smith, S. Strauch, G. Gavalian, B. A. Clary, N. Hirlinger Saylor, Michael Paolone, N. A. Baltzell, K. Joo, H. Egiyan, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CLAS, and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
Subjects: electron p: deep inelastic scattering, interference: Bethe-Heitler, Nuclear and High Energy Physics, generalized parton distribution, Proton, accelerator, electron: polarized beam, Hadronic Physics and QCD, FOS: Physical sciences, Socio-culturale, parton: distribution function, Parton, Newport News CEBAF Linac, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], momentum transfer dependence, 01 natural sciences, beam: energy, High Energy Physics - Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare, x-dependence, Nuclear physics, Cross section (physics), High Energy Physics - Experiment (hep-ex), spectrometer: acceptance, High Energy Physics - Phenomenology (hep-ph), deeply virtual Compton scattering, CLAS, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Quantum chromodynamics, Physics, Spectrometer, 010308 nuclear & particles physics, Compton scattering, cross section: difference, HERA, magnetic spectrometer, photon: electroproduction, High Energy Physics - Phenomenology, kinematics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Nucleon, channel cross section: measured, experimental results
Abstract: This paper reports the measurement of polarized and unpolarized cross sections for the ep -> e'p' reaction, which is comprised of Deeply Virtual Compton Scattering (DVCS) and Bethe-Heitler (BH) processes, at an electron beam energy of 5.88 GeV at the Thomas Jefferson National Accelerator Facility using the Large Acceptance Spectrometer CLAS. The unpolarized cross sections and polarized cross section differences have been measured over broad kinematics, 0.10 < x_B < 0.58, 1.0 < Q^2 < 4.8 GeV^2, and 0.09 < -t < 2.00 GeV^2. The results are found to be consistent with previous CLAS data, and these new data are discussed in the framework of the generalized parton distribution approach. Calculations with two widely used phenomenological models, denoted VGG and KMSC, are approximately compatible with the experimental results over a large portion of the kinematic range of the data., 27 pages, 24 figures, Accepted for publication in PRC
Published: 2018

22. Probing high-momentum protons and neutrons in neutron-rich nuclei

Author: D. Bulumulla, B. S. Ishkhanov, B. A. Clary, C. E. Hyde, T. Mineeva, Adi Ashkenazi, P. Eugenio, Alexander Schmidt, K. Livingston, Pawel Nadel-Turonski, M. Taiuti, J. Arrington, Y. Prok, A. I. Ostrovidov, G. Gavalian, M. Contalbrigo, Michael Paolone, R. A. Schumacher, M. L. Kabir, A. D'Angelo, C. Munoz-Camacho, A. Beck, G. Ciullo, J. P. Ball, G. Laskaris, D. S. Carman, L. Lanza, Shalev Gilad, G. Khachatryan, A. Rizzo, F. Hauenstein, D. G. Ireland, R. G. Fersch, E. De Sanctis, S. Mey-Tal Beck, A. Movsisyan, M. Battaglieri, P. L. Cole, Z. W. Zhao, S. Stepanyan, George Davey Smith, Volker D. Burkert, A. S. Biselli, G. Charles, Nicholas M. Harrison, Gerard Gilfoyle, Y. Ilieva, Andreas Klein, J. Poudel, D. Sokhan, M. Patsyuk, K. Hicks, D. P. Watts, Taya Chetry, B. McKinnon, H. Egiyan, S. Nadeeshani, X. Wei, P. Lenisa, N. Markov, W. J. Briscoe, W. Kim, K. P. Adhikari, Douglas Higinbotham, M. Mirazita, Maxime Defurne, R. Cruz-Torres, I. Bedlinskiy, S. Niccolai, Chaden Djalali, M. Osipenko, L. El Fassi, L. Guo, D. Payette, Or Hen, Eliahu Cohen, K.A. Griffoen, B. Schmookler, M. Braverman, L. Barion, R. De Vita, A. El Alaoui, G. E. Dodge, Andrea Celentano, K. Hafidi, M. Khandaker, S. Procureur, Friedrich Klein, T. A. Forest, F. X. Girod, M. J. Amaryan, Nicholas Zachariou, F. Cao, M. Ripani, I. J. D. MacGregor, E.P. Segarra, Eli Piasetzky, I. Korover, Afroditi Papadopoulou, S. Strauch, J. W. Price, G. Rosner, A. Filippi, M. Duer, K. L. Giovanetti, O. Pogorelko, Larry Weinstein, B. Mustapha, G. Niculescu, E. Pasyuk, W. Phelps, N. Dashyan, E. L. Isupov, O. Cortes, R. W. Gothe, S. Boiarinov, Y. Ghandilyan, M. Holtrop, S. Bueltmann, Victor Mokeev, M. Ungaro, J. Zhang, D. Protopopescu, K. Joo, E. Voutier, Y. G. Sharabian, A. Kim, William Brooks, C. Marchand, V. Batourine, F. Sabatié, David M. Keller, J. A. Tan, V. Crede, R. A. Montgomery, H. Hakobyan, Laura Clark, P. Rossi, X. Zheng, M. Khachatryan, Nikolaos Sparveris, S. E. Kuhn, M. Hattawy, A. Deur, S. Adhikari, E. Golovatch, R. Dupre, K. Park, I. Balossino, H. Voskanyan, Carlos A. Salgado, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), CLAS, and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
Subjects: Quark, Multidisciplinary matter, Proton, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Astrophysics::High Energy Astrophysical Phenomena, EMC effect, Nuclear Theory, momentum spectrum, Socio-culturale, parton: distribution function, Electron, 7. Clean energy, 01 natural sciences, nucleon: momentum, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, CLAS, 0103 physical sciences, Neutron, 010306 general physics, Nuclear Experiment, neutron star, p nucleus: scattering, Physics, Multidisciplinary, 010308 nuclear & particles physics, electron nucleus: scattering, quantum mechanics, Nuclear shell model, shell model, correlation, Atomic nucleus, Nucleon
Abstract: International audience; The atomic nucleus is one of the densest and most complex quantum-mechanical systems in nature. Nuclei account for nearly all the mass of the visible Universe. The properties of individual nucleons (protons and neutrons) in nuclei can be probed by scattering a high-energy particle from the nucleus and detecting this particle after it scatters, often also detecting an additional knocked-out proton. Analysis of electron- and proton-scattering experiments suggests that some nucleons in nuclei form close-proximity neutron–proton pairs 1$^{–}$12 with high nucleon momentum, greater than the nuclear Fermi momentum. However, how excess neutrons in neutron-rich nuclei form such close-proximity pairs remains unclear. Here we measure protons and, for the first time, neutrons knocked out of medium-to-heavy nuclei by high-energy electrons and show that the fraction of high-momentum protons increases markedly with the neutron excess in the nucleus, whereas the fraction of high-momentum neutrons decreases slightly. This effect is surprising because in the classical nuclear shell model, protons and neutrons obey Fermi statistics, have little correlation and mostly fill independent energy shells. These high-momentum nucleons in neutron-rich nuclei are important for understanding nuclear parton distribution functions (the partial momentum distribution of the constituents of the nucleon) and changes in the quark distributions of nucleons bound in nuclei (the EMC effect) 1$^{,}$13$^{,}$14 . They are also relevant for the interpretation of neutrino-oscillation measurements 15 and understanding of neutron-rich systems such as neutron stars 3$^{,}$16 .
Published: 2018

23. Measurement of the helicity asymmetry E in ω→π+π−π0 photoproduction

Author: M. Contalbrigo, T. Mineeva, R. A. Schumacher, Z. Akbar, M. Khachatryan, V. Mokeev, Taya Chetry, A. V. Anisovich, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, E. Golovatch, F. Cao, P. Roy, M. Guidal, B. S. Ishkhanov, K. Hicks, C. Gleason, Iu. Skorodumina, Nikos Sparveris, X. Wei, M. Holtrop, O. Cortes, K. P. Adhikari, C. D. Keith, E. L. Isupov, M. Ripani, Barry Ritchie, E. Voutier, Nicholas Zachariou, S. Stepanyan, Laura Clark, L. Guo, H. Egiyan, S. Boiarinov, G. Khachatryan, A. Movsisyan, I. J. D. MacGregor, E. De Sanctis, G. Charles, J. Brock, Sylvester Joosten, M. Hattawy, Carlos A. Salgado, A. Celentano, R. W. Gothe, A. V. Sarantsev, S. Park, M. Osipenko, F. Sabatié, W. J. Briscoe, I. I. Strakovsky, Y. G. Sharabian, S. Niccolai, M. Ungaro, D. I. Sober, A. I. Ostrovidov, K. Park, Michael Paolone, R. Dupre, M. Battaglieri, C. Munoz Camacho, A. Filippi, G. V. Fedotov, A. Deur, K. A. Griffioen, V. Crede, D. G. Ireland, W. Phelps, Lorenzo Zana, S. Adhikari, N. Dashyan, D. Protopopescu, Alessandro Rizzo, M. Garçon, Volker D. Burkert, B. McKinnon, W. K. Brooks, D. G. Jenkins, I. Bedlinskiy, V. A. Nikonov, Brian Raue, P. Nadel-Turonski, A. Fradi, F. X. Girod, W. Kim, I. Denisenko, V. Batourine, Michael Dugger, G. Rosner, N. Markov, R. Paremuzyan, S. Strauch, Andreas Klein, K. Livingston, W. Gohn, R. De Vita, C. Carlin, Nicholas M. Harrison, S. Anefalos Pereira, L. Lanza, D. Sokhan, A. Kim, C. Djalali, C. Hanretty, R. Fersch, H. Avakian, Eberhard Klempt, J. Zhang, H. Voskanyan, E. Pasyuk, J. W. Price, George Davey Smith, V. P. Kubarovsky, D. G. Meekins, A. D'Angelo, O. Pogorelko, Frank Klein, Dustin Keller, L. El Fassi, Michael Wood, K. Hafidi, P. L. Cole, Z. W. Zhao, P. Eugenio, M. Taiuti, N. Gevorgyan, D. Heddle, G. Hollis, Hrachya Hakobyan, M. J. Amaryan, K. L. Giovanetti, and M. Khandaker
Subjects: Physics, Meson, 010308 nuclear & particles physics, Partial wave analysis, Bremsstrahlung, Resonance, Observable, 01 natural sciences, Helicity, Nuclear physics, Pomeron, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: The double-polarization observable E was studied for the reaction γp → pω using the CEBAF Large Acceptance Spectrometer (CLAS) in Hall B at the Thomas Jefferson National Accelerator Facility and the longitudinally polarized frozen-spin target (FROST). The observable was measured from the charged decay mode of the meson, ω → π+π−π0, using a circularly polarized tagged-photon beam with energies ranging from the ω threshold at 1.1 to 2.3 GeV. A partial-wave analysis within the Bonn-Gatchina framework found dominant contributions from the 3/2+ partial wave near threshold, which is identified with the subthreshold N(1720) 3/2+ nucleon resonance. To describe the entire data set, which consisted of ω differential cross sections and a large variety of polarization observables, further contributions from other nucleon resonances were found to be necessary. With respect to nonresonant mechanisms, π exchange in the t channel was found to remain small across the analyzed energy range, while Pomeron t-channel exchange gradually grew from the reaction threshold to dominate all other contributions above W ≈ 2 GeV.
Published: 2017

24. Determination of the proton spin structure functions for 0.05<Q2<5GeV2 using CLAS

Author: N. Harrison, V. Crede, Y. Prok, A. Simonyan, R. A. Montgomery, P. Lenisa, N. Zachariou, H. Egiyan, L. Clark, N. K. Walford, M. Ungaro, N. Dashyan, R. W. Gothe, A. D'Angelo, G. P. Gilfoyle, C. Salgado, L. Colaneri, P. Bosted, P. Eugenio, I. Balossino, R. G. Fersch, Friedrich Klein, E. L. Isupov, M. Taiuti, W. Phelps, M. Contalbrigo, G. Gavalian, F. Cao, K. Hicks, G. Murdoch, P. Roy, M. Guidal, Taya Chetry, G. E. Dodge, C. Hanretty, M. Khandaker, M. Holtrop, M. Garçon, K. Hafidi, I. Bedlinskiy, J. A. Fleming, J. Ball, M. Hattawy, M. Osipenko, Iu. Skorodumina, B. S. Ishkhanov, D. Protopopescu, D. Heddle, D. Keller, Z. Akbar, Marco Ripani, J. Zhang, Michael Paolone, C. Djalali, C. A. Meyer, E. Voutier, G. V. Fedotov, O. Cortes, D. P. Watts, K. Griffioen, H. Voskanyan, V. Kubarovsky, C. Keith, W. K. Brooks, P. Rossi, Ye Tian, F. Sabatié, L. B. Weinstein, S. L. Careccia, I. I. Strakovsky, A. Rizzo, A. Deur, C. Gleason, R. Paremuzyan, W. Kim, D. Sokhan, S. Pisano, L. Elouadrhiri, G. Niculescu, S. E. Kuhn, D. Riser, A. El Alaoui, S. Stepanyan, O. Pogorelko, H. Avakian, B. A. Raue, A. I. Ostrovidov, G. Asryan, D. G. Ireland, Y. Ilieva, Volker D. Burkert, A. S. Biselli, R. Dupre, K. L. Giovanetti, G. Ciullo, D. A. Jenkins, K. Livingston, D. S. Carman, Nikos Sparveris, S. Niccolai, X. Wei, L. Lanza, V. G. Lagerquist, B. Torayev, E. Pasyuk, I. Stankovic, A. Movsisyan, N. Guler, M. Mirazita, C. Munoz Camacho, N. Compton, Hrachya Hakobyan, B. McKinnon, E. De Sanctis, A. Klein, H. Y. Lu, R. De Vita, S. Anefalos Pereira, K. Joo, S. Chandavar, A. Filippi, M. J. Amaryan, E. Fanchini, L. Guo, J. W. Price, S. M. Hughes, R. Minehart, R. A. Schumacher, V. Mokeev, K. P. Adhikari, T. A. Forest, J. Pierce, S. Bultmann, E. Golovatch, P. Nadel-Turonski, I. Niculescu, S. Adhikari, G. Khachatryan, W. J. Briscoe, G. Charles, L. El Fassi, P. L. Cole, Andrea Celentano, A. Kim, G. D. Smith, F. X. Girod, S. Strauch, M. Khachatryan, Y. G. Sharabian, G. Rosner, N. A. Baltzell, Y. Ghandilyan, K. Park, and M. Battaglieri
Subjects: Quantum chromodynamics, Physics, Particle physics, Proton, 010308 nuclear & particles physics, Virtual particle, Parton, Deep inelastic scattering, 01 natural sciences, Nuclear physics, 0103 physical sciences, Proton spin crisis, High Energy Physics::Experiment, Operator product expansion, Nuclear Experiment, 010306 general physics, Spin-½
Abstract: We present the results of our final analysis of the full data set of g1p(Q2), the spin structure function of the proton, collected using CLAS at Jefferson Laboratory in 2000–2001. Polarized electrons with energies of 1.6, 2.5, 4.2, and 5.7 GeV were scattered from proton targets (NH315 dynamically polarized along the beam direction) and detected with CLAS. From the measured double spin asymmetries, we extracted virtual photon asymmetries A1p and A2p and spin structure functions g1p and g2p over a wide kinematic range (0.05 GeV2
Published: 2017

25. Measurement of the differential and total cross sections of the γd→K0Λ(p) reaction within the resonance region

Author: H. Hakobyan, M. Taiuti, Dustin Keller, N. Compton, N. Dashyan, D. I. Glazier, R. De Vita, Michael Wood, K. Hafidi, Laura Clark, Yordanka Ilieva, X. Wei, C. E. Hyde, A. Simonyan, M. Osipenko, L. Guo, Alessandro Rizzo, S. Anefalos Pereira, K. Hicks, R. Paremuzyan, R. A. Schumacher, W. Phelps, V. P. Kubarovsky, V. Crede, A. El Alaoui, J. A. Fleming, O. Pogorelko, S. M. Hughes, P. Nadel-Turonski, G. Murdoch, R. A. Montgomery, Michael Paolone, G. Gavalian, N. K. Walford, M. Camp, G. Charles, V. Mokeev, C. Gleason, Nicholas Zachariou, E. De Sanctis, K. P. Adhikari, Nicholas M. Harrison, T. Cao, H. Avakian, H. S. Jo, F. X. Girod, N. Markov, I. J. D. MacGregor, D. Heddle, C. Hanretty, Barry Ritchie, H. Voskanyan, S. Pisano, P. Lenisa, M. Contalbrigo, Avraham Klein, D. Sokhan, F. Sabatié, H. Y. Lu, G. Rosner, M. Khachatryan, I. Stankovic, Philip L. Cole, Z. Akbar, S. Adhikari, B. McKinnon, Nikolaos Sparveris, I. Bedlinskiy, E. Munevar, W. Kim, P. L. Cole, K. Livingston, Y. Ghandilyan, I. Niculescu, Friedrich Klein, D. G. Jenkins, G. Niculescu, B. S. Ishkhanov, A. D'Angelo, Taya Chetry, R. W. Gothe, Eberhard Klempt, M. Mirazita, L. El Fassi, V. Batourine, J. Zhang, S. Stepanyan, G. Khachatryan, Brian Raue, J. W. Price, Latifa Elouadrhiri, C. A. Meyer, Sergey Kuleshov, M. Ripani, M. Ungaro, A. I. Ostrovidov, K. Park, G. V. Fedotov, F. Cao, D. G. Ireland, V. A. Nikonov, Volker D. Burkert, A. S. Biselli, W. J. Briscoe, K. Joo, C. Munoz Camacho, I. I. Strakovsky, M. Guidal, Y. G. Sharabian, G. Ciullo, Y. Prok, T. Mineeva, D. S. Carman, D. Protopopescu, A. Deur, E. Voutier, S. Niccolai, A. Movsisyan, Iu. Skorodumina, W. K. Brooks, G. D. Smith, M. Holtrop, C. E. Taylor, E. Golovatch, R. Dupre, S. Strauch, D. P. Watts, H. Egiyan, A. V. Sarantsev, M. Battaglieri, B. Torayev, K. L. Giovanetti, A. Filippi, M. Khandaker, O. Cortes, E. L. Isupov, A. Fradi, Sylvester Joosten, L. Lanza, Eugene Pasyuk, Andrea Celentano, C. Djalali, N. A. Baltzell, C. Salgado, K. A. Griffioen, A. Trivedi, and P. Eugenio
Subjects: Physics, Particle physics, 010308 nuclear & particles physics, Partial wave analysis, Quark model, Gamma ray, Bremsstrahlung, Resonance, Lambda, 01 natural sciences, Particle identification, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: We report the first measurement of differential and total cross sections for the $\ensuremath{\gamma}d\ensuremath{\rightarrow}{K}^{0}\mathrm{\ensuremath{\Lambda}}(p)$ reaction, using data from the CLAS detector at the Thomas Jefferson National Accelerator Facility. Data collected during two separate experimental runs were studied with photon-energy coverage 0.8--3.6 GeV and 0.5-- 2.6 GeV, respectively. The two measurements are consistent giving confidence in the method and determination of systematic uncertainties. The cross sections are compared with predictions from the KAON-MAID theoretical model (without kaon exchange), which deviate from the data at higher $W$ and at forward kaon angles. These data, along with previously published cross sections for ${K}^{+}\mathrm{\ensuremath{\Lambda}}$ photoproduction, provide essential constraints on the nucleon resonance spectrum. A first partial wave analysis was performed that describes the data without the introduction of new resonances.
Published: 2017

26. First measurement of the polarization observable E in the p→(γ→,π+)n reaction up to 2.25 GeV

Author: I. Zonta, William Brooks, X. Wei, P. Lenisa, K. Livingston, D. P. Watts, Friedrich Klein, A. V. Sarantsev, D. Rönchen, P. Nadel-Turonski, Z. W. Zhao, Eberhard Klempt, W. Gohn, F. Sabatié, R. A. Badui, H. Y. Lu, I. Niculescu, I. I. Strakovsky, B. A. Raue, R. A. Schumacher, A. El Alaoui, Barry Ritchie, J. W. Price, A. Deur, Nicholas Zachariou, K. A. Griffioen, S. Chandavar, A. V. Anisovich, L. Guo, M. Ungaro, M. Ripani, R. W. Gothe, Michael Döring, T. A. Forest, S. Stepanyan, E. Munevar, Avraham Klein, Iu. Skorodumina, P. Eugenio, C. I. Moody, M. Taiuti, V. Crede, V. A. Nikonov, Latifa Elouadrhiri, G. Khachatryan, C. A. Meyer, G.V. O'Rielly, A. Trivedi, K. Joo, G. V. Fedotov, Andrea Celentano, Andrew Puckett, R. A. Montgomery, A. Kim, E. Golovatch, R. Dupre, S. Procureur, D. Keller, R. De Vita, D. Protopopescu, M. Contalbrigo, D. G. Jenkins, S. Pozdniakov, I. Bedlinskiy, K. P. Adhikari, N. Benmouna, F. X. Girod, J. Brock, H. S. Jo, N. Compton, Jian Zhang, C. Carlin, A. Filippi, Nikolaos Sparveris, N. Gevorgyan, W. Kim, S. Strauch, D. S. Carman, Victor Mokeev, G. Niculescu, D. Ho, K. Park, L. Colaneri, M. Khandaker, John Phillips, A. Simonyan, E. Seder, N. Markov, S. Pisano, N. K. Walford, M. Hattawy, D. I. Glazier, E. Voutier, T. Cao, A. Fradi, O. Pogorelko, D. G. Meekins, Diane Schott, G. Rosner, I. J. D. MacGregor, A. I. Ostrovidov, M. Osipenko, D. G. Ireland, H. Moutarde, M. Battaglieri, Y. Ghandilyan, H. Jiang, B. S. Ishkhanov, Volker D. Burkert, S. E. Kuhn, A. S. Biselli, K. L. Giovanetti, J. A. Fleming, L. El Fassi, P. Peng, Hovanes Egiyan, Chaden Djalali, Michael Dugger, Hrachya Hakobyan, Y. Ilieva, C. Munoz Camacho, R. Tucker, Ron L. Workman, P. L. Cole, B. McKinnon, L. A. Net, S. Fegan, Eugene Pasyuk, S. Anefalos Pereira, Y. G. Sharabian, W. Phelps, V. Batourine, M. L. Seely, D. Sokhan, E. De Sanctis, C. D. Keith, J. P. Ball, Y. Prok, D. I. Sober, A. Rizzo, S. Niccolai, C. Hanretty, V. Sytnik, N. Harrison, A. Movsisyan, N. Dashyan, P. Stoler, I. Senderovich, K. Hicks, G. Charles, P. Roy, D. Adikaram, M. Guidal, S. Joosten, G. D. Smith, M. Holtrop, H. Voskanyan, W. J. Briscoe, V. P. Kubarovsky, Annalisa D'Angelo, S. M. Hughes, Michael Wood, K. Hafidi, O. Cortes, E. L. Isupov, Ye Tian, Lorenzo Zana, and C. Salgado
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Photon, Pion, Meson, Bremsstrahlung, Observable, Photon energy, Nuclear Experiment, Multipole expansion, Nucleon
Abstract: First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction (p) over right arrow((gamma) over right arrow, pi(+))n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been included in new multipole analyses resulting in updated nucleon resonance parameters. We report updated fits from the Bonn-Gatchina, Jfilich-Bonn, and SAID groups. (C) 2015 The Authors. Published by Elsevier B.V.
Published: 2015

27. First Exclusive Measurement of Deeply Virtual Compton Scattering off He4 : Toward the 3D Tomography of Nuclei

Author: M. J. Amaryan, Laura Clark, C. Gleason, P. Lenisa, W. Phelps, H. Moutarde, X. Wei, K. A. Griffioen, B. S. Ishkhanov, K. L. Giovanetti, Taya Chetry, M. Hattawy, Hovanes Egiyan, Larry Weinstein, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, P. Eugenio, E. Golovatch, S. Strauch, J. W. Price, Friedrich Klein, L. Guo, Alessandro Rizzo, C. Munoz Camacho, D. G. Ireland, E. Voutier, Latifa Elouadrhiri, R. De Vita, V. Crede, M. Taiuti, C. Djalali, Michael Paolone, A. Movsisyan, O. Cortes, E. L. Isupov, S. Niccolai, Z. W. Zhao, C. A. Meyer, H. Y. Lu, L. Lanza, Whitney Armstrong, A. I. Ostrovidov, K. Park, G. V. Fedotov, D. P. Watts, G. Rosner, R. A. Montgomery, A. Celentano, Martin K. Mayer, R. W. Gothe, K. Livingston, A. Deur, H. Jiang, Volker D. Burkert, A. S. Biselli, D. G. Jenkins, R. Paremuzyan, Sergey Kuleshov, M. Khachatryan, A. Simonyan, Y. Ghandilyan, V. I. Mokeev, D. Heddle, H. Hakobyan, M. H. Wood, R. Dupre, S. Boiarinov, L. Colaneri, Iu. Skorodumina, S. Adhikari, S. Anefalos Pereira, S. Fegan, Jie Zhang, I. Niculescu, F. Cao, E. Pasyuk, Nikolaos Sparveris, N. Markov, K. Hicks, D. Adikaram, B. Torayev, M. Guidal, G. Charles, F. X. Girod, Z. E. Meziani, Nicholas M. Harrison, Gerard Gilfoyle, I. Bedlinskiy, N. A. Baltzell, C. Hanretty, W. Kim, P. Nadel-Turonski, William Brooks, A. Filippi, G. D. Smith, M. Holtrop, Lorenzo Zana, G. Khachatryan, M. Battaglieri, G. Niculescu, E. Seder, R. G. Fersch, F. Sabatié, W. Gohn, P. Rossi, V. P. Kubarovsky, D. Sokhan, P. L. Cole, M. Khandaker, O. Pogorelko, D. Protopopescu, B. G. Ritchie, M. Bashkanov, R. A. Schumacher, M. Ungaro, S. M. Hughes, M. Garçon, N. Dashyan, A. D'Angelo, E. De Sanctis, Sylvester Joosten, B. McKinnon, M. E. McCracken, L. A. Net, L. El Fassi, C. Salgado, M. Osipenko, Dustin Keller, A. El Alaoui, N. K. Walford, Y. Perrin, T. Mineeva, Nicholas Zachariou, S. Bültmann, M. Mirazita, E. Phelps, K. P. Adhikari, T. A. Forest, K. Hafidi, N. Gevorgyan, I. J. D. MacGregor, V. Batourine, H. Avakian, S. Stepanyan, Y. G. Sharabian, S. Pisano, K. Joo, Simonetta Liuti, Avraham Klein, M. Contalbrigo, H. Voskanyan, A. Kim, W. J. Briscoe, A. Fradi, S. E. Kuhn, J. A. Fleming, Z. Akbar, and M. Ripani
Subjects: Physics, Particle physics, Time projection chamber, Photon, Proton, Meson, 010308 nuclear & particles physics, Compton scattering, General Physics and Astronomy, Electron, HERA, 01 natural sciences, 7. Clean energy, Nuclear physics, Recoil, 0103 physical sciences, Physics::Accelerator Physics, Nuclear Experiment, 010306 general physics
Abstract: We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized $^{4}\mathrm{He}$ gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles. To ensure the exclusivity of the process, a specially designed radial time projection chamber is used to detect the recoiling $^{4}\mathrm{He}$ nuclei. We measure beam-spin asymmetries larger than those observed on the free proton in the same kinematic domain. From these, we are able to extract, in a model-independent way, the real and imaginary parts of the only $^{4}\mathrm{He}$ Compton form factor, ${\mathcal{H}}_{A}$. This first measurement of coherent deeply virtual Compton scattering on the $^{4}\mathrm{He}$ nucleus, with a fully exclusive final state via nuclear recoil tagging, leads the way toward 3D imaging of the partonic structure of nuclei.
Published: 2017

28. Differential cross section measurements for γn→π−p above the first nucleon resonance region

Author: P. Eugenio, W. Kim, G. Niculescu, B. S. Ishkhanov, A. E. Kudryavtsev, A. Simonyan, Z. E. Meziani, V. P. Kubarovsky, S. M. Hughes, D. Adikaram, M. Guidal, X. Wei, K. Livingston, D. P. Watts, Michael Paolone, I. Bedlinskiy, H. Voskanyan, H. S. Jo, C. Salgado, A. Celentano, R. W. Gothe, R. A. Schumacher, Maxime Defurne, Dustin Keller, P. Lenisa, Jie Zhang, Michael Wood, K. Hafidi, P. Mattione, R. Fersch, G. D. Smith, M. Holtrop, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, R. Paremuzyan, M. Osipenko, Alfred Švarc, Nicholas M. Harrison, Gerard Gilfoyle, Nikos Sparveris, I. I. Strakovsky, R. De Vita, S. V. Kuleshov, E. Voutier, K. P. Adhikari, D. Sokhan, S. Stepanyan, K. L. Giovanetti, N. Markov, A. Deur, D. G. Jenkins, A. Movsisyan, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, Friedrich Klein, G. Rosner, N. K. Walford, T. Cao, S. Pisano, F. X. Girod, I. J. D. MacGregor, Laura Clark, Avraham Klein, P. L. Cole, Brian Raue, M. Bashkanov, S. Adhikari, B. McKinnon, S. Anefalos Pereira, S. Niccolai, M. Contalbrigo, O. Pogorelko, Z. W. Zhao, Victor Mokeev, A. I. Ostrovidov, A. Filippi, M. Ungaro, K. Park, I. Niculescu, J. W. Price, M. Taiuti, M. Ripani, D. Protopopescu, D. G. Ireland, V. Batourine, M. Khandaker, Z. Akbar, H. Jiang, E. De Sanctis, A. D'Angelo, Y. Ghandilyan, Volker D. Burkert, A. S. Biselli, O. Cortes, V. Crede, H. Hakobyan, K. Joo, L. El Fassi, Hovanes Egiyan, C. Munoz Camacho, E. L. Isupov, D. Heddle, E. Golovatch, G. Khachatryan, K. Hicks, R. A. Montgomery, P. Nadel-Turonski, Chaden Djalali, S. Boiarinov, Michael Dugger, T. Mineeva, G. Hollis, Taya Chetry, W. Phelps, W. J. Briscoe, Alessandro Rizzo, C. Hanretty, S. Procureur, A. Fradi, Ron L. Workman, S. Strauch, L. Lanza, Eugene Pasyuk, L. A. Net, N. A. Baltzell, R. Dupre, M. Battaglieri, K. A. Griffioen, Y. G. Sharabian, M. Khachatryan, G. Charles, J. A. Fleming, F. Sabatié, C. A. Meyer, G. V. Fedotov, Iu. Skorodumina, G. Murdoch, C. Gleason, Barry Ritchie, M. Hattawy, Sylvester Joosten, A. Kim, N. Dashyan, I. Stankovic, and V. E. Tarasov
Subjects: Physics, Particle physics, Photon, 010308 nuclear & particles physics, Bremsstrahlung, Resonance, State (functional analysis), 01 natural sciences, Particle identification, Pion, Amplitude, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon
Abstract: The quasifree $\ensuremath{\gamma}d\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}p(p)$ differential cross section has been measured with CLAS at photon beam energies ${E}_{\ensuremath{\gamma}}$ from 0.445 to 2.510 GeV (corresponding to $W$ from 1.311 to 2.366 GeV) for pion center-of-mass angles $cos{\ensuremath{\theta}}_{\ensuremath{\pi}}^{c.m.}$ from $\ensuremath{-}0.72$ to 0.92. A correction for final state interactions has been applied to these data to extract the $\ensuremath{\gamma}n\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{-}}p$ differential cross sections. These cross sections are quoted in 8428 $({E}_{\ensuremath{\gamma}},cos{\ensuremath{\theta}}_{\ensuremath{\pi}}^{c.m.})$ bins, a factor of nearly 3 increase in the world statistics for this channel in this kinematic range. These new data help to constrain coupled-channel analysis fits used to disentangle the spectrum of ${N}^{*}$ resonances and extract their properties. Selected photon decay amplitudes ${N}^{*}\ensuremath{\rightarrow}\ensuremath{\gamma}n$ at the resonance poles are determined for the first time and are reported here.
Published: 2017

29. Measurements of ep→e′π+π−p′ cross sections with CLAS at 1.40GeV<W<2.0 GeV and 2.0GeV2<Q2<5.0GeV2

Author: Y. Ilieva, W. Kim, Nicholas Zachariou, G. Niculescu, L. Colaneri, C. Salgado, J. W. Price, Latifa Elouadrhiri, H. Y. Lu, I. Stankovic, H. Hakobyan, D. Protopopescu, M. Garçon, E. Voutier, G. V. Fedotov, B. G. Ritchie, R. G. Fersch, Taya Chetry, K. Park, V. I. Mokeev, C. Munoz Camacho, G. Murdoch, M. Osipenko, D. Heddle, C. Gleason, D. G. Ireland, P. L. Cole, H. Jiang, P. Eugenio, O. Cortes, E. L. Isupov, Laura Clark, M. Hattawy, P. Lenisa, Volker D. Burkert, Ye Tian, A. S. Biselli, W. Phelps, I. Niculescu, D. I. Glazier, Sergey Kuleshov, K. Livingston, S. Adhikari, R. De Vita, B. McKinnon, B. Torayev, X. Wei, Jie Zhang, D. Adikaram, M. Guidal, G. Gavalian, M. J. Amaryan, Eugene Pasyuk, S. Anefalos Pereira, G. D. Smith, M. Holtrop, M. Mirazita, I. I. Strakovsky, V. Batourine, V. Crede, A. Deur, Y. G. Sharabian, Michael Paolone, R. A. Schumacher, E. De Sanctis, S. Niccolai, R. Paremuzyan, R. A. Montgomery, K. L. Giovanetti, A. Kim, Nicholas M. Harrison, Gerard Gilfoyle, W. K. Brooks, J. A. Fleming, D. Sokhan, N. Markov, S. Bültmann, A. D'Angelo, D. G. Jenkins, K. P. Adhikari, T. A. Forest, E. Munevar, Avraham Klein, F. X. Girod, A. Filippi, L. El Fassi, M. Ungaro, K. Hicks, A. Trivedi, M. Khandaker, M. Ripani, I. Bedlinskiy, Friedrich Klein, T. Mineeva, Brian Raue, Iu. Skorodumina, L. Guo, E. Golovatch, R. Dupre, Alessandro Rizzo, K. Joo, C. Hanretty, G. Charles, C. Djalali, F. Sabatié, G. Khachatryan, K. A. Griffioen, P. Nadel-Turonski, B. S. Ishkhanov, W. J. Briscoe, Sylvester Joosten, L. Lanza, S. Procureur, M. C. Kunkel, S. Strauch, M. Battaglieri, Y. Ghandilyan, M. Contalbrigo, M. Taiuti, Z. Akbar, N. K. Walford, T. Cao, I. J. D. MacGregor, A. Celentano, R. W. Gothe, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, N. A. Baltzell, Nikos Sparveris, Dustin Keller, A. Movsisyan, N. Dashyan, Michael Wood, K. Hafidi, A. Simonyan, V. P. Kubarovsky, D. Riser, O. Pogorelko, S. M. Hughes, H. Avakian, H. Voskanyan, and A. El Alaoui
Subjects: Nuclear physics, Baryon, Scattering cross-section, Physics, Particle physics, 010308 nuclear & particles physics, 0103 physical sciences, Pi interaction, 010306 general physics, Nucleon, 01 natural sciences, Resonance (particle physics), Energy (signal processing)
Abstract: This paper reports new exclusive cross sections for $ep\ensuremath{\rightarrow}{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{p}^{\ensuremath{'}}$ using the CLAS detector at Jefferson Laboratory. These results are presented for the first time at photon virtualities $2.0\phantom{\rule{0.16em}{0ex}}{\mathrm{GeV}}^{2}\phantom{\rule{4pt}{0ex}}l{Q}^{2}l5.0\phantom{\rule{4pt}{0ex}}{\mathrm{GeV}}^{2}$ in the center-of-mass energy range 1.4 GeV $lWl$ 2.0 GeV, which covers a large part of the nucleon resonance region. Using a model developed for the phenomenological analysis of electroproduction data, we see strong indications that the relative contributions from the resonant cross sections at $Wl1.74$ GeV increase with ${Q}^{2}$. These data considerably extend the kinematic reach of previous measurements. Exclusive $ep\ensuremath{\rightarrow}{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{p}^{\ensuremath{'}}$ cross section measurements are of particular importance for the extraction of resonance electrocouplings in the mass range above 1.6 GeV.
Published: 2017

30. Differential cross sections and polarization observables from CLAS K* photoproduction and the search for new N* states

Author: G. Khachatryan, W. J. Briscoe, R. A. Schumacher, G. Rosner, Y. Ghandilyan, Andrew Puckett, P. Lenisa, C. Hanretty, N. K. Walford, Michael Dugger, C. A. Meyer, Nikolaos Sparveris, I. J. D. MacGregor, R. A. Badui, C. Djalali, V. Crede, R. W. Gothe, A. I. Ostrovidov, K. Park, W. Phelps, M. J. Amaryan, F. Sabatié, L. El Fassi, G. V. Fedotov, D. A. Jenkins, Friedrich Klein, M. Battaglieri, Brian Raue, E. Fanchini, R. A. Montgomery, P. Peng, I. Zonta, Hovanes Egiyan, C. Munoz Camacho, D. G. Ireland, Eberhard Klempt, L. A. Net, E. De Sanctis, J. W. Price, L. Clark, H. Jiang, Z. Akbar, K. L. Giovanetti, I. Bedlinskiy, A. Deur, R. Paremuzyan, H. S. Jo, F. X. Girod, N. Compton, Volker D. Burkert, A. S. Biselli, Nicholas M. Harrison, Y. G. Sharabian, M. Ripani, D. Sokhan, L. Guo, B. McKinnon, A. Ni, A. Filippi, M. Contalbrigo, I. Stankovic, P. Nadel-Turonski, Michael Paolone, E. Munevar, M. Ungaro, B. S. Ishkhanov, M. Mirazita, M. Khandaker, R. Dupre, I. Niculescu, W. Tang, Sylvester Joosten, K. A. Griffioen, V. Batourine, P. L. Cole, R. De Vita, M. Osipenko, E. L. Isupov, Iu. Skorodumina, V. A. Nikonov, Ye Tian, J. A. Fleming, W. Kim, S. Anefalos Pereira, A. D'Angelo, L. Lanza, V. Sytnik, K. Hicks, P. Eugenio, N. Markov, S. Pisano, Victor Mokeev, G. Murdoch, Andrea Celentano, P. Roy, D. Adikaram, N. Gevorgyan, C. Gleason, Barry Ritchie, J. Ball, M. Hattawy, G. D. Smith, M. Holtrop, Taya Chetry, N. Dashyan, K. Livingston, Jie Zhang, S. Stepanyan, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, E. Voutier, V. P. Kubarovsky, O. Pogorelko, S. M. Hughes, Dustin Keller, Michael Wood, H. Voskanyan, E. Pasyuk, G. Ciullo, Y. Prok, D. S. Carman, S. Strauch, D. P. Watts, S. Niccolai, A. Movsisyan, A. V. Sarantsev, S. Chandavar, A. V. Anisovich, Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), CLAS, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Polarization observables, Photon, experimental methods, magnetic field, 01 natural sciences, B004:Desig=16, Settore FIS/04 - Fisica Nucleare e Subnucleare, Recoil, electron: recoil, B016.178, N(2100), B144:Desig=19, B071:Desig=179, electron: beam, photon: tagged beam, spin: density matrix, B132:Desig=13, Nuclear Experiment, B087.14, Physics, B005.22, B144.19, Bremsstrahlung, Lambda: polarization, B004.16, Polarization (waves), Breit-Wigner, B005:Desig=22, lcsh:QC1-999, Meson photoproduction, resonance, differential cross section, Baryon spectroscopy, branching ratio, missing-mass, Jefferson Lab, B016:Desig=178, Nuclear and High Energy Physics, Particle physics, B006.21, Partial wave analysis, B006:Desig=21, Socio-culturale, Photon energy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], polarization: recoil, bremsstrahlung, Nuclear physics, CLAS, 0103 physical sciences, B024.15, 010306 general physics, 010308 nuclear & particles physics, Branching fraction, Resonance, B132.13, partial wave analysis, B087:Desig=14, meson: photoproduction, B024:Desig=15, 4.02 GeV, baryon: hadron spectroscopy, High Energy Physics::Experiment, B071.179, lcsh:Physics, dipole, experimental results
Abstract: The reaction γp→K⁎+Λ was measured using the CLAS detector for photon energies between the threshold and 3.9 GeV at the Thomas Jefferson National Accelerator Facility. For the first time, spin-density matrix elements have been extracted for this reaction. Differential cross sections, spin density matrix elements, and the Λ recoil polarization are compared with theoretical predictions using the BnGa partial wave analysis. The main result is the evidence for significant contributions from N(1895)1/2− and N(2100)1/2+ to the reaction. Branching ratios for decays into K⁎Λ for these resonances and further resonances are reported.
Published: 2017

31. Measurement of two-photon exchange effect by comparing elastic e±p cross sections

Author: V. Crede, D. A. Jenkins, Lorenzo Zana, Y. G. Sharabian, L. Lanza, Hovanes Egiyan, C. Munoz Camacho, K. Livingston, L. Clark, G. V. Fedotov, P. Lenisa, C. Salgado, L. El Fassi, H. Voskanyan, K. A. Griffioen, Jie Zhang, B. McKinnon, M. D. Mestayer, O. Cortes, E. L. Isupov, Andrei Afanasev, S. Boiarinov, M. Taiuti, K. P. Adhikari, L. Guo, M. Mirazita, Z. Akbar, R. Fersch, Alessandro Rizzo, S. E. Kuhn, A. I. Ostrovidov, S. Stepanyan, N. Gevorgyan, V. Batourine, F. X. Girod, C. Hanretty, G. Khachatryan, J. A. Fleming, K. Park, N. Compton, C. Gleason, P. Eugenio, D. G. Ireland, K. L. Giovanetti, H. Jiang, W. Gohn, Larry Weinstein, V. P. Kubarovsky, W. J. Briscoe, Volker D. Burkert, R. Paremuzyan, J. W. Price, V. I. Mokeev, A. Ni, O. Pogorelko, S. M. Hughes, J. Ball, W. Kim, A. S. Biselli, M. Hattawy, Friedrich Klein, E. Golovatch, G. Niculescu, Gerard Gilfoyle, Taya Chetry, D. Heddle, D. Protopopescu, R. Dupre, E. Voutier, Michael Paolone, S. Strauch, D. Sokhan, Dustin Keller, I. Bedlinskiy, Brian Raue, P. Rossi, R. De Vita, Z. W. Zhao, A. D'Angelo, I. Zonta, F. Sabatié, Michael Wood, K. Hafidi, K. Hicks, Eugene Pasyuk, X. Wei, B. Torayev, P. L. Cole, N. K. Walford, S. Anefalos Pereira, E. Seder, W. Phelps, Andrew Puckett, D. Rimal, A. Filippi, Sergey Kuleshov, A. Deur, A. El Alaoui, M. Osipenko, M. Contalbrigo, Y. Ilieva, M. Khandaker, Nikolaos Sparveris, N. A. Baltzell, A. Fradi, Nicholas Zachariou, I. J. D. MacGregor, R. A. Badui, G. Rosner, V. Sytnik, L. Colaneri, Y. Ghandilyan, N. Markov, S. Pisano, N. Dashyan, P. Roy, Chaden Djalali, D. Adikaram, Iu. Skorodumina, I. Stankovic, R. W. Gothe, G. D. Smith, M. Holtrop, B. S. Ishkhanov, G. Ciullo, Y. Prok, D. S. Carman, N. Harrison, S. Niccolai, A. Movsisyan, P. Nadel-Turonski, Sylvester Joosten, M. Battaglieri, M. Ungaro, R. A. Schumacher, S. Bültmann, T. A. Forest, E. Munevar, Avraham Klein, William Brooks, Andrea Celentano, H. Y. Lu, I. Niculescu, J. Arrington, E. Fanchini, D. P. Watts, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and CLAS Collaboration
Subjects: ratio, Proton, radiative-corrections, Socio-culturale, FOS: Physical sciences, Electron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, Electron-proton scattering, Nuclear physics, 0103 physical sciences, form-factors, positron-proton, 4-momentum transfers, clas, hydrogen, beam, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Elastic scattering, Physics, 010308 nuclear & particles physics, Scattering, Electric form factor, Physics::Accelerator Physics, High Energy Physics::Experiment, Atomic physics, Electron scattering, Beam (structure), Lepton
Abstract: [Background] The electromagnetic form factors of the proton measured by unpolarized and polarized electron scattering experiments show a significant disagreement that grows with the squared four momentum transfer ($Q^{2}$). Calculations have shown that the two measurements can be largely reconciled by accounting for the contributions of two-photon exchange (TPE). TPE effects are not typically included in the standard set of radiative corrections since theoretical calculations of the TPE effects are highly model dependent, and, until recently, no direct evidence of significant TPE effects has been observed. [Purpose] We measured the ratio of positron-proton to electron-proton elastic-scattering cross sections in order to determine the TPE contribution to elastic electron-proton scattering and thereby resolve the proton electric form factor discrepancy. [Methods] We produced a mixed simultaneous electron-positron beam in Jefferson Lab's Hall B by passing the 5.6 GeV primary electron beam through a radiator to produce a bremsstrahlung photon beam and then passing the photon beam through a convertor to produce electron/positron pairs. The mixed electron-positron (lepton) beam with useful energies from approximately 0.85 to 3.5 GeV then struck a 30-cm long liquid hydrogen (LH$_2$) target located within the CEBAF Large Acceptance Spectrometer (CLAS). By detecting both the scattered leptons and the recoiling protons we identified and reconstructed elastic scattering events and determined the incident lepton energy. A detailed description of the experiment is presented., Comment: 21 pages, 22 figures
Published: 2017

32. Photon beam asymmetry Σ for η and η′ photoproduction from the proton

Author: K. A. Griffioen, I. I. Strakovsky, S. Strauch, H. Egiyan, Michael Dugger, Sylvester Joosten, Latifa Elouadrhiri, C. A. Meyer, Michael Paolone, P. Eugenio, M. Taiuti, A. Deur, K. Livingston, G. V. Fedotov, R. A. Schumacher, N. Markov, W. Phelps, W. K. Brooks, M. Osipenko, S. Pisano, F. X. Girod, E. Golovatch, R. Dupre, M. Ungaro, A. V. Sarantsev, X. Wei, G. Murdoch, M. Ripani, V. Crede, P. Collins, Iu. Skorodumina, M. Khachatryan, P. Nadel-Turonski, F. Sabatié, L. Lanza, C. Gleason, Michael Döring, D. Heddle, K. P. Adhikari, D. Sadasivan, R. Paremuzyan, N. K. Walford, A. Kim, J. W. Price, V. A. Nikonov, A. I. Ostrovidov, K. Park, Taya Chetry, S. Stepanyan, D. I. Glazier, G. Khachatryan, Barry Ritchie, G. Charles, R. A. Montgomery, Avraham Klein, C. Djalali, A. El Alaoui, Y. Ilieva, J. Ball, W. Kim, D. G. Ireland, G. Niculescu, V. P. Kubarovsky, R. De Vita, Volker D. Burkert, Nicholas Zachariou, H. S. Jo, S. Chandavar, A. V. Anisovich, A. S. Biselli, I. Bedlinskiy, I. J. D. MacGregor, M. Battaglieri, W. J. Briscoe, N. Compton, O. Pogorelko, S. M. Hughes, Nicholas M. Harrison, Gerard Gilfoyle, K. Hicks, B. Torayev, D. G. Jenkins, E. Fanchini, Y. G. Sharabian, H. Avakian, M. J. Amaryan, S. Anefalos Pereira, I. Niculescu, P. Lenisa, D. Sokhan, L. Guo, H. Hakobyan, O. Cortes, E. L. Isupov, Alessandro Rizzo, Laura Clark, H. Voskanyan, Eberhard Klempt, V. Mokeev, Ye Tian, D. Protopopescu, E. De Sanctis, M. Bashkanov, M. Contalbrigo, P. L. Cole, J. A. Fleming, E. Pasyuk, E. Voutier, C. Hanretty, J. Zhang, B. McKinnon, G. Ciullo, Friedrich Klein, Brian Raue, F. Cao, P. Roy, Y. Prok, D. S. Carman, K. L. Giovanetti, Nikos Sparveris, I. Balossino, G. Rosner, D. Rönchen, Dustin Keller, M. Mirazita, S. Niccolai, A. Movsisyan, B. S. Ishkhanov, C. Salgado, N. Dashyan, A. D'Angelo, A. Filippi, Z. Akbar, Y. Ghandilyan, K. Hafidi, M. Khandaker, G. D. Smith, M. Holtrop, A. Celentano, R. W. Gothe, L. El Fassi, C. Munoz Camacho, and L. Colaneri
Subjects: Nuclear and High Energy Physics, Photon, Proton, Meson, Meson photoproduction, Eta photoproduction, Eta-prime photoproduction, Polarization observable, Photon beam asymmetry, Nuclear Theory, Photon energy, 01 natural sciences, Particle identification, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Physics, 010308 nuclear & particles physics, Bremsstrahlung, Particle Data Group, lcsh:QC1-999, High Energy Physics::Experiment, Atomic physics, Nucleon, lcsh:Physics
Abstract: Measurements of the linearly-polarized photon beam asymmetry Σ for photoproduction from the proton of η and η′ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the γp→ηp reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the γp→η′p reaction. For γp→ηp, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For γp→η′p, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. Initial analysis of the data reported here with the Bonn–Gatchina model strengthens the evidence for four nucleon resonances – the N(1895)1/2−, N(1900)3/2+, N(2100)1/2+ and N(2120)3/2− resonances – which presently lack the “four-star” status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process.
Published: 2017

33. Exclusive η electroproduction at W>2 GeV with CLAS and transversity generalized parton distributions

Author: P. Eugenio, B. S. Ishkhanov, B. Torayev, C. E. Hyde, H. Hakobyan, R. De Vita, P. Nadel-Turonski, K. Livingston, I. Zonta, X. Wei, P. Stoler, W. Kim, S. Anefalos Pereira, G. Niculescu, A. Celentano, R. W. Gothe, R. A. Schumacher, K. L. Giovanetti, K. Hicks, Y. Prok, E. Golovatch, Nicholas M. Harrison, Gerard Gilfoyle, F. Sabatié, Larry Weinstein, D. G. Jenkins, G. Ciullo, J. P. Ball, R. Dupre, D. S. Carman, D. Sokhan, Eugene Pasyuk, E. De Sanctis, A. Ni, Laura Clark, L. Guo, R. G. Fersch, Alessandro Rizzo, K. P. Adhikari, T. A. Forest, N. A. Baltzell, E. Fanchini, P. L. Cole, G. Rosner, P. Lenisa, S. Stepanyan, K. A. Griffioen, A. Filippi, B. McKinnon, Igor Strakovsky, S. Niccolai, C. Hanretty, Dustin Keller, M. Osipenko, F. X. Girod, A. Movsisyan, A. El Alaoui, Y. Ilieva, Sergey Kuleshov, Nicholas Zachariou, A. D'Angelo, G. Charles, M. Khandaker, N. K. Walford, M. Mirazita, N. Dashyan, Y. Ghandilyan, P. Rossi, T. Cao, L. El Fassi, Michael Wood, Friedrich Klein, I. Bedlinskiy, J. Zhang, N. Gevorgyan, V. Batourine, I. J. D. MacGregor, Brian Raue, W. Phelps, E. L. Isupov, Ye Tian, M. Contalbrigo, V. Crede, H. Avakian, M. Ungaro, M. Taiuti, G. Khachatryan, H. Voskanyan, R. A. Montgomery, L. Colaneri, Iu. Skorodumina, S. Boiarinov, Z. Akbar, P. Roy, M. Turisini, P. Peng, C. Munoz Camacho, K. Joo, M. Guidal, H. S. Jo, N. Markov, A. Deur, S. Pisano, R. Paremuzyan, W. J. Briscoe, M. Yurov, G. D. Smith, J. W. Price, V. P. Kubarovsky, O. Pogorelko, S. M. Hughes, D. Protopopescu, A. I. Ostrovidov, K. Park, M. Garçon, E. Voutier, Victor Mokeev, D. G. Ireland, H. Jiang, C. Gleason, Z. E. Meziani, Volker D. Burkert, A. S. Biselli, C. Salgado, M. Hattawy, Michael Paolone, Chaden Djalali, Latifa Elouadrhiri, K. Hafidi, L. Lanza, M. Battaglieri, G. V. Fedotov, M. Ripani, S. Chandavar, Andrew Puckett, S. Strauch, M. Khachatryan, D. P. Watts, M. S. Saini, Nikolaos Sparveris, L. A. Net, Y. G. Sharabian, S. E. Kuhn, J. A. Fleming, A. Kim, and Sylvester Joosten
Subjects: Physics, Particle physics, Meson, 010308 nuclear & particles physics, Quark model, Structure function, Hadron, Sigma, Parton, Elementary particle, 01 natural sciences, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Boson
Abstract: The cross section of the exclusive eta electroproduction reaction ep -> e'p'eta was measured at Jefferson Laboratorywith a 5.75 GeV electron beam and the CLAS detector. Differential cross sections d(4) sigma/dtdQ(2) dx(B)d phi(eta) and structure functions sigma(U) = sigma(T) + epsilon sigma(L), sigma(TT), and sigma(LT), as functions of t, were obtained over a wide range of Q(2) and x(B). The eta structure functions are compared with those previously measured for pi(0) at the same kinematics. At low t, both pi(0) and eta are described reasonably well by generalized parton distributions (GPDs) in which chiral-odd transversity GPDs are dominant. The pi(0) and eta data, when taken together, can facilitate the flavor decomposition of the transversity GPDs.
Published: 2017

34. Beam-target double-spin asymmetry in quasielastic electron scattering off the deuteron with CLAS

Author: N. Compton, Chaden Djalali, R. A. Schumacher, F. X. Girod, R. Paremuzyan, S. Bültmann, Gerard Gilfoyle, T. A. Forest, C. D. Keith, I. Zonta, M. Osipenko, G. Khachatryan, Laura Clark, F. Sabatié, D. Sokhan, Marco Contalbrigo, S. Stepanyan, L. Guo, W. J. Briscoe, Avraham Klein, B. McKinnon, G. Asryan, C. Hanretty, S. Strauch, G. Charles, W. Kim, P. Rossi, R. A. Badui, M. Mirazita, G. Niculescu, J. W. Price, S. Niccolai, W. Phelps, P. Eugenio, V. Sytnik, Alessandro Rizzo, Victor Mokeev, G. Rosner, A. Deur, L. Lanza, M. Taiuti, L. Colaneri, M. Ungaro, W. K. Brooks, S. E. Kuhn, Y. Prok, Y. Ghandilyan, A. Celentano, R. W. Gothe, K. A. Griffioen, A. Kim, C. E. Hyde, B. S. Ishkhanov, J. A. Fleming, E. De Sanctis, V. Crede, J. P. Ball, M. H. Wood, R. Dupre, M. Battaglieri, Taya Chetry, D. S. Carman, Hrachya Hakobyan, B. Torayev, I. u. Skorodumina, I. Bedlinskiy, Z. Akbar, E. Fanchini, P. Bosted, K. Hicks, M. Guidal, R. De Vita, K. L. Giovanetti, A. I. Ostrovidov, K. Park, P. L. Cole, M. Holtrop, L. A. Net, E. Voutier, J. Zhang, Paolo Lenisa, D. G. Ireland, H. Jiang, A. Movsisyan, Volker D. Burkert, A. S. Biselli, H. Avakian, S. Anefalos Pereira, N. K. Walford, I. J. D. MacGregor, Latifa Elouadrhiri, George Davey Smith, G. V. Fedotov, Y. G. Sharabian, H. Voskanyan, D. G. Meekins, A. D'Angelo, Andrew Puckett, Martin K. Mayer, L. El Fassi, E. Pasyuk, M. Khachatryan, K. P. Adhikari, E. L. Isupov, N. A. Baltzell, Ye Tian, S. Boiarinov, Nikolaos Sparveris, C. Gleason, M. Ripani, V. P. Kubarovsky, O. Pogorelko, S. M. Hughes, N. Dashyan, Dustin Keller, I. Stankovic, Yordanka Ilieva, Giuseppe Ciullo, A. El Alaoui, Nicholas Zachariou, K. Livingston, M. Hattawy, R. Fersch, N. Guler, Larry Weinstein, A. Filippi, M. Khandaker, Old Dominion University [Norfolk] (ODU), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), CLAS Collaboration, and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Particle physics, Nuclear and High Energy Physics, POLARIZED TARGET, media_common.quotation_subject, Hadron, Nuclear Theory, FOS: Physical sciences, Socio-culturale, Inelastic scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Asymmetry, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Economica, 0103 physical sciences, Neutron, ELECTRODISINTEGRATION, Nuclear Experiment (nucl-ex), 010306 general physics, NUCLEON, Nuclear Experiment, QC, media_common, FORM-FACTOR, NEUTRON, STATE, Physics, 010308 nuclear & particles physics, Scattering, Momentum transfer, Quasielastic neutron scattering, Nucleon
Abstract: Quasi-elastic electron scattering on the deuteron is a benchmark reaction to test our understanding of deuteron structure and the properties and interactions of the two nucleons bound in the deuteron. The experimental data presented here can be used to test state-of-the-art models of the deuteron and the two-nucleon interaction in the final state after two-body breakup of the deuteron. Focusing on polarization degrees of freedom, we gain information on spin-momentum correlations in the deuteron ground state (due to the D-state admixture) and on the limits of the Impulse Approximation (IA) picture as it applies to measurements of spin-dependent observables like spin structure functions for bound nucleons. We measured the beam-target double spin asymmetry for quasi-elastic electron scattering off the deuteron at several beam energies using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. The deuterons were polarized along (or opposite to) the beam direction. The double spin asymmetries were measured as a function of photon virtuality , missing momentum, and the angle between the (inferred) "spectator" neutron and the momentum transfer direction. The results are compared with a recent model that includes Final State Interactions (FSI) using a complete parameterization of nucleon-nucleon scattering, as well as a simplified model using the Plane Wave Impulse Approximation (PWIA). We find overall good agreement with both the PWIA and FSI expectations at low to medium missing momenta, including the change of the asymmetry due to the contribution of the deuteron D-state at higher momenta. At the highest missing momenta, our data clearly agree better with the calculations including FSI., Comment: 19 pages, 17 figures, to be submitted to PRC
Published: 2017

35. Target and double spin asymmetries of deeply virtual π 0 production with a longitudinally polarized proton target and CLAS

Author: E. Seder, G. V. Fedotov, K. P. Adhikari, D. G. Ireland, V. Sytnik, V. Crede, B. McKinnon, A. Kim, M. Ungaro, Dustin Keller, G. Khachatryan, W. Phelps, M. Contalbrigo, A. Fradi, D. P. Watts, A. D'Angelo, H. Egiyan, P. Nadel-Turonski, H. Y. Lu, P. Mattione, P. Bosted, P. Roy, E. De Sanctis, M. Osipenko, L. Colaneri, L. El Fassi, M. Battaglieri, Sylvester Joosten, H. S. Jo, S. Pisano, K. Hafidi, D. G. Jenkins, N. Compton, Michael Paolone, C. Hanretty, P. Lenisa, M. E. McCracken, V. Batourine, I. I. Strakovsky, I. J. D. MacGregor, B. S. Ishkhanov, Z. Akbar, K. Joo, W. Kim, N. Markov, F. X. Girod, Lorenzo Zana, K. A. Griffioen, R. A. Badui, G. D. Smith, M. Holtrop, S. E. Kuhn, L. Guo, Alessandro Rizzo, C. Djalali, Friedrich Klein, J. A. Fleming, Gerard Gilfoyle, P. Rossi, V. P. Kubarovsky, C. Salgado, D. Sokhan, M. Ripani, O. Pogorelko, E. Golovatch, A. Celentano, R. W. Gothe, L. Lanza, S. Chandavar, M. Garc con, J. W. Price, I. Bedlinskiy, R. G. Fersch, H. Avakian, A. I. Ostrovidov, R. De Vita, K. Park, Y. Prok, D. S. Carman, Iu. Skorodumina, P. L. Cole, J. Zhang, L. A. Net, O. Cortes, Nikos Sparveris, William Brooks, H. Voskanyan, H. Jiang, X. Wei, Taya Chetry, W. J. Briscoe, E. Pasyuk, S. Niccolai, G. Rosner, S. Boiarinov, S. Anefalos Pereira, A. Movsisyan, P. Eugenio, Volker D. Burkert, A. S. Biselli, N. Dashyan, M. Taiuti, Y. G. Sharabian, Y. Ghandilyan, T. Cao, R. A. Schumacher, M. Hattawy, W. Gohn, S. Bültmann, S. Stepanyan, E. Munevar, Avraham Klein, Sergey Kuleshov, V. Mokeev, G. Charles, S. Strauch, P. Stoler, K. Hicks, E. Voutier, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, D. Heddle, B. Torayev, A. Filippi, M. Khandaker, K. L. Giovanetti, Larry Weinstein, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and CLAS Collaboration
Subjects: Particle physics, Nuclear and High Energy Physics, media_common.quotation_subject, Deeply Virtual Meson Production, Virtual particle, Socio-culturale, Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Asymmetry, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Nucleon structure, 0103 physical sciences, Chiral-odd generalized parton distributions, CLAS collaboration, Longitudinally polarized target, 010306 general physics, Nuclear Experiment, media_common, Physics, Spectrometer, 010308 nuclear & particles physics, lcsh:QC1-999, Pseudoscalar, Transverse plane, Amplitude, Phase space, High Energy Physics::Experiment, lcsh:Physics
Abstract: The target and double spin asymmetries of the exclusive pseudoscalar channel View the MathML source were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of Q2, xB, −t and ϕ . Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs) provides the first insight on the chiral-odd GPDs View the MathML source and ET, and complement previous measurements of unpolarized structure functions sensitive to the GPDs HT and View the MathML source. These data provide a crucial input for parametrizations of essentially unknown chiral-odd GPDs and will strongly influence existing theoretical calculations based on the handbag formalism.
Published: 2017

36. Performance of the Muon g−2 calorimeter and readout systems measured with test beam data

Author: D.A. Peterson, M. Bartolini, K. L. Giovanetti, N.T. Rider, A. Kuchibhotla, A. Gioiosa, S. Ganguly, A.T. Fienberg, A. Chapelain, H. P. Binney, W. Gohn, R. Bjorkquist, J. Kaspar, C. Schlesier, T. P. Gorringe, M. Iacovacci, A. Driutti, A. Lusiani, S. Leo, M. W. Smith, T. Stuttard, D. W. Hertzog, G. Pauletta, S. Mastroianni, L. K. Gibbons, Dinko Pocanic, G. Venanzoni, Claudio Ferrari, D.A. Sweigart, T. D. Van Wechel, K. S. Khaw, J.B. Hempstead, C. Gabbanini, and A. Fioretti
Subjects: Physics, Nuclear and High Energy Physics, Muon, Calorimeter (particle physics), Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, business.industry, Electrical engineering, 7. Clean energy, 01 natural sciences, Silicon photomultiplier, Data acquisition, 0103 physical sciences, Calibration, Waveform, Fermilab, Electronics, 010306 general physics, business, Instrumentation
Abstract: A single calorimeter station for the Muon g − 2 experiment at Fermilab includes the following subsystems: a 54-element array of PbF 2 Cherenkov crystals read out by large-area SiPMs, bias and slow-control electronics, a suite of 800 MSPS waveform digitizers, a clock and control distribution network, a gain calibration and monitoring system, and a GPU-based front-end which is read out through a MIDAS data acquisition environment. The entire system performance was evaluated using 2.5–5 GeV electrons at the End Station Test Beam at SLAC. This paper includes a description of the individual subsystems and the results of measurements of the energy response and resolution, energy-scale stability, timing resolution, and spatial uniformity. All measured performances meet or exceed the g − 2 experimental requirements. Based on the success of the tests, the complete production of the required 24 calorimeter stations has been made and installation into the main experiment is complete. Furthermore, the calorimeter response measurements reported here informed the design of the reconstruction algorithms that are now employed in the running g − 2 experiment.
Published: 2019

37. Target and beam-target spin asymmetries in exclusive π+ and π− electroproduction with 1.6- to 5.7-GeV electrons

Author: N. Dashyan, Taya Chetry, I. Stankovic, Yordanka Ilieva, Sergey Kuleshov, C. Djalali, A. Filippi, H. Avakian, G. Charles, George Davey Smith, W. Gohn, N. A. Baltzell, D. G. Jenkins, I. I. Strakovsky, A. Deur, P. Bosted, P. Roy, D. Adikaram, F. X. Girod, R. A. Schumacher, S. Strauch, A. D'Angelo, B. McKinnon, E. Munevar, G. Niculescu, P. Eugenio, M. Taiuti, S. Joosten, M. Ungaro, D. Heddle, B. S. Ishkhanov, G. Ciullo, A. El Alaoui, Nicholas Zachariou, M. Holtrop, S. Bültmann, W. Kim, L. El Fassi, K. P. Adhikari, T. A. Forest, V. Crede, D. P. Watts, I. Zonta, S. Stepanyan, R. W. Gothe, Andrew Puckett, C. Gleason, J. Pierce, Avraham Klein, K. A. Griffioen, M. E. McCracken, P. Nadel-Turonski, E. Golovatch, R. Dupre, Carlos A. Salgado, K. Joo, M. Mirazita, B. Torayev, G. E. Dodge, H. Y. Lu, S. M. Hughes, K. Livingston, R. A. Badui, N. Gevorgyan, I. Bedlinskiy, H. S. Jo, A. Fradi, A. Simonyan, M. J. Amaryan, J. P. Ball, V. Sytnik, R. Fersch, D. S. Carman, M. Hattawy, M. Osipenko, N. Guler, Nikos Sparveris, P. Lenisa, W. J. Briscoe, I. Niculescu, X. Wei, E. Voutier, A. Movsisyan, S. L. Careccia, S. Niccolai, S. E. Kuhn, J. A. Fleming, V. P. Kubarovsky, S. Chandavar, V. Batourine, Victor Mokeev, A. Ni, D. Protopopescu, M. Garçon, A. Celentano, O. Pogorelko, Alessandro Rizzo, L. Lanza, Friedrich Klein, P. Rossi, K. L. Giovanetti, R. De Vita, E. Fanchini, E. Seder, P. Peng, Hovanes Egiyan, Larry Weinstein, C. Munoz Camacho, C. Hanretty, Brian Raue, M. Khandaker, M. Ripani, R. C. Minehart, S. Anefalos Pereira, C. A. Meyer, J. Zhang, R. Paremuzyan, H. Voskanyan, L. A. Net, G. V. Fedotov, J. W. Price, G. Rosner, S. Boiarinov, E. Pasyuk, Gerard Gilfoyle, Y. Ghandilyan, Dustin Keller, P. L. Cole, Z. W. Zhao, A. I. Ostrovidov, K. Park, Michael Wood, K. Hafidi, D. G. Ireland, H. Jiang, Y. G. Sharabian, Volker D. Burkert, X. Zheng, A. S. Biselli, L. Colaneri, N. Markov, S. Pisano, M. Battaglieri, S. Procureur, O. Cortes, E. L. Isupov, Ye Tian, Lorenzo Zana, L. Clark, K. Hicks, L. Guo, G. Asryan, N. Harrison, Iu. Skorodumina, W. Phelps, Y. Prok, F. Sabatié, M. Contalbrigo, Z. Akbar, N. K. Walford, T. Cao, and I. J. D. MacGregor
Subjects: Physics, Particle physics, 010308 nuclear & particles physics, Scattering, Resonance, Electron, Polarization (waves), Deep inelastic scattering, 01 natural sciences, Particle identification, Nuclear physics, Amplitude, 0103 physical sciences, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: Beam-target double spin asymmetries and target single-spin asymmetries in exclusive $\pi^+$ and $\pi^-$ electroproduction were obtained from scattering of 1.6 to 5.7 GeV longitudinally polarized electrons from longitudinally polarized protons (for $\pi^+$) and deuterons (for $\pi^-$) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The kinematic range covered is $1.1 1.5$ GeV. Very large target-spin asymmetries are observed for $W>1.6$ GeV. When combined with cross section measurements, the present results will provide powerful constraints on nucleon resonance amplitudes at moderate and large values of $Q^2$, for resonances with masses as high as 2.3 GeV.
Published: 2016

38. Measurement of target and double-spin asymmetries for the e⃗p⃗→eπ+(n) reaction in the nucleon resonance region at low Q2

Author: P. Roy, M. Guidal, V. Crede, S. Joosten, O. Pogorelko, Andrea Celentano, G. D. Smith, M. Holtrop, A. I. Ostrovidov, Paolo Rossi, Karl Slifer, D. G. Ireland, Andrew Puckett, R. A. Schumacher, Chaden Djalali, H. S. Jo, H. Jiang, Y. Ilieva, B. McKinnon, L. C. Smith, E. Munevar, I. Zonta, S. Strauch, Volker D. Burkert, A. S. Biselli, M. Osipenko, B. S. Ishkhanov, G. Ciullo, D. Keller, Nikolaos Sparveris, Taya Chetry, L. Colaneri, G. Khachatryan, Michael Paolone, P. Eugenio, M. Taiuti, S. Bültmann, Hyekoo Kang, L. El Fassi, P. Nadel-Turonski, H. Avakian, D. P. Watts, J. P. Ball, L. Clark, R. De Vita, A. Rizzo, M. Khandaker, D. G. Jenkins, X. Wei, M. Mirazita, A. Ni, S. Niccolai, L. Lanza, K. Hicks, R. W. Gothe, C. Salgado, M. J. Amaryan, N. Guler, A. Movsisyan, H. Egiyan, A. Filippi, G. Charles, Gerard Gilfoyle, I. I. Strakovsky, F. X. Girod, D. Adikaram, D. Sokhan, G. Murdoch, N. Markov, Seonho Choi, R. Paremuzyan, S. E. Kuhn, M. Battaglieri, K. Livingston, H. Voskanyan, E. Fanchini, K. L. Giovanetti, V. A. Drozdov, A. Deur, J. A. Fleming, J. P. Chen, E. Pasyuk, K. Kovacs, C. Gleason, G. E. Dodge, N. Gevorgyan, Larry Weinstein, C. Hanretty, W. Kim, W. J. Briscoe, F. Sabatié, E. De Sanctis, S. Pisano, S. K. Phillips, G. Niculescu, V. Batourine, S. Chandavar, N. A. Baltzell, R. Fersch, P. Bosted, E. Voutier, N. K. Walford, P. Lenisa, J. W. Price, P. Peng, L. Guo, M. Hattawy, I. Niculescu, G. Asryan, K. A. Griffioen, C. Munoz Camacho, I. Bedlinskiy, S. M. Hughes, E. N. Golovach, Victor Mokeev, P. L. Cole, N. Dashyan, K. Park, Iu. Skorodumina, R. Dupre, A. El Alaoui, I. Stankovic, R. A. Badui, I. J. D. MacGregor, M. Contalbrigo, Friedrich Klein, Brian Raue, Nicholas Zachariou, E. L. Isupov, G. V. Fedotov, N. Harrison, M. Ripani, L. A. Net, A. Kim, G. Rosner, N. Compton, Ye Tian, V. P. Kubarovsky, Annalisa D'Angelo, K. P. Adhikari, Z. Akbar, L. Elouadrhiri, S. Anefalos Pereira, Michael Wood, Y. G. Sharabian, Y. Ghandilyan, X. Zheng, J. Zhang, D. S. Carman, M. Ungaro, and E. Long
Subjects: Physics, Particle physics, 010308 nuclear & particles physics, Scattering, Cherenkov detector, media_common.quotation_subject, Electron, 01 natural sciences, Resonance (particle physics), Asymmetry, law.invention, Nuclear physics, law, 0103 physical sciences, Isobar, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, Spin-½, media_common
Abstract: We report measurements of target- and double-spin asymmetries for the exclusive channel $\vec e\vec p\to e\pi^+ (n)$ in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH$_3$ target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3 and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low $Q^2$ range from $0.0065$ to $0.35$ (GeV$/c$)$^2$. The $Q^2$ access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as $6^\circ$. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.
Published: 2016

39. Photoproduction ofΛandΣ0hyperons using linearly polarized photons

Author: W. Kim, Michael Dugger, A. El Alaoui, Y. Ilieva, G. Niculescu, P. Peng, Hovanes Egiyan, C. Munoz Camacho, Nicholas Zachariou, R. A. Schumacher, D. G. Jenkins, V. P. Kubarovsky, A. I. Ostrovidov, K. Park, M. Contalbrigo, O. Pogorelko, S. M. Hughes, V. Crede, N. Compton, M. J. Amaryan, A. Ni, D. G. Ireland, H. Jiang, Dustin Keller, P. Lenisa, B. McKinnon, K. P. Adhikari, Volker D. Burkert, A. S. Biselli, J. A. Fleming, F. X. Girod, I. I. Strakovsky, I. Zonta, M. Taiuti, K. Hafidi, X. Wei, A. Deur, M. Osipenko, E. Munevar, Friedrich Klein, Iu. Skorodumina, Z. Akbar, M. Ungaro, Brian Raue, L. Clark, N. Gevorgyan, L. A. Net, H. Y. Lu, K. L. Giovanetti, W. K. Brooks, D. Protopopescu, R. A. Badui, P. Roy, C. Salgado, Y. G. Sharabian, C. Gleason, R. Paremuzyan, D. Adikaram, E. Voutier, H. Voskanyan, Andrew Puckett, J. W. Price, Barry Ritchie, W. J. Briscoe, R. Dupre, M. Hattawy, Gerard Gilfoyle, Nikolaos Sparveris, D. I. Glazier, A. Celentano, R. W. Gothe, A. Filippi, L. Guo, L. Colaneri, D. Sokhan, S. Niccolai, F. Sabatié, O. Cortes, E. L. Isupov, K. Livingston, G. D. Smith, M. Holtrop, M. Khandaker, S. Strauch, C. A. Paterson, Jie Zhang, N. Markov, R. De Vita, E. Seder, S. Pisano, G. V. Fedotov, P. Mattione, M. Ripani, D. P. Watts, K. Joo, N. K. Walford, G. Ciullo, J. P. Ball, Y. Prok, D. S. Carman, I. Bedlinskiy, S. Anefalos Pereira, Eugene Pasyuk, A. Rizzo, V. Sytnik, N. Harrison, I. J. D. MacGregor, A. Movsisyan, B. Torayev, E. Fanchini, K. A. Griffioen, Taya Chetry, D. I. Sober, Sergey Kuleshov, Victor Mokeev, P. Nadel-Turonski, K. Hicks, L. Lanza, C. Djalali, M. Battaglieri, M. E. McCracken, A. D'Angelo, G. Khachatryan, L. El Fassi, C. A. Mayer, R. Tucker, P. L. Cole, N. A. Baltzell, B. S. Ishkhanov, L. Zana, G. Rosner, and Y. Ghandilyan
Subjects: Physics, Quantum chromodynamics, Particle physics, Photon, 010308 nuclear & particles physics, Linear polarization, Bremsstrahlung, Strangeness, 01 natural sciences, Particle identification, Nuclear physics, Baryon, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: Background: Measurements of polarization observables for the reactions (gamma) over right arrowp -> K+ Lambda and (gamma) over right arrowp -> K+ Sigma(0) have been performed. This is part of a program of measurements designed to study the spectrum of baryon resonances in particular, and nonperturbative QCD in general. Purpose: The accurate measurement of several polarization observables provides tight constraints for phenomenological fits, which allow the study of strangeness in nucleon and nuclear systems. Beam-recoil observables for the (gamma) over right arrowp -> K+ Sigma(0) reaction have not been reported before now. Method: Themeasurements were carried out using linearly polarized photon beams incident on a liquid hydrogen target, and the CLAS detector at the Thomas Jefferson National Accelerator Facility. The energy range of the results is 1.71 < W < 2.19 GeV, with an angular range -0.75 < cos theta(K)* < +0.85. Results: The observables extracted for both reactions are beam asymmetry Sigma, target asymmetry T, and the beam-recoil double polarization observables O-x and O-z. Conclusions: Comparison with theoretical fits indicates that, in the regions where no previous data existed, the new data contain significant new information, and strengthen the evidence for the set of resonances used in the latest Bonn-Gatchina fit.
Published: 2016

40. Photoproduction of the f(1)(1285) meson

Author: Nicholas Zachariou, E. Voutier, P. Lenisa, K. Livingston, V. Mokeev, Jie Zhang, I. Zonta, R. A. Badui, I. I. Strakovsky, F. X. Girod, N. Dashyan, A. Filippi, N. Compton, L. Colaneri, B. S. Ishkhanov, R. De Vita, M. Khandaker, C. Djalali, K. Park, A. Deur, V. Sytnik, L. Zana, G. Rosner, A. Celentano, I. Stankovic, R. W. Gothe, A. Ni, K. Hicks, S. Chandavar, W. Phelps, M. Battaglieri, N. Markov, W. Kim, S. Pisano, Friedrich Klein, Gerard Gilfoyle, Brian Raue, M. Ripani, M. Contalbrigo, S. Anefalos Pereira, Y. Ghandilyan, P. Roy, D. Sokhan, H. Y. Lu, P. L. Cole, J. W. Price, P. Nadel-Turonski, B. McKinnon, Dustin Keller, P. Mattione, M. Taiuti, Iu. Skorodumina, M. J. Amaryan, V. Crede, G. Khachatryan, A. I. Ostrovidov, S. Strauch, M. Ungaro, Michael Dugger, M. Mirazita, Z. Akbar, D. P. Watts, G. Ciullo, Eugene Pasyuk, J. A. Fleming, H. Hakobyan, D. G. Ireland, S. Joosten, H. Jiang, Y. Prok, D. S. Carman, L. Guo, N. Gevorgyan, K. L. Giovanetti, V. Batourine, G. D. Smith, M. Holtrop, A. Rizzo, Volker D. Burkert, A. S. Biselli, H. S. Jo, R. A. Schumacher, R. Dupre, A. Kim, K. A. Griffioen, Michael Wood, D. Weygand, K. Hafidi, C. Hanretty, N. Harrison, M. Osipenko, Andrew Puckett, L. Lanza, E. De Sanctis, N. K. Walford, I. Bedlinskiy, Taya Chetry, K. P. Adhikari, I. J. D. MacGregor, S. Stepanyan, E. Munevar, Nikolaos Sparveris, D. I. Sober, T. Cao, A. D'Angelo, E. Fanchini, L. El Fassi, Elton Smith, Ryan Dickson, L. A. Net, V. P. Kubarovsky, Y. G. Sharabian, Sergey Kuleshov, P. Eugenio, G. Charles, O. Pogorelko, S. M. Hughes, H. Voskanyan, W. J. Briscoe, Kei Moriya, C. A. Meyer, G. V. Fedotov, G. Murdoch, C. Salgado, J. Ball, M. Hattawy, O. Cortes, E. L. Isupov, S. Boiarinov, E. Seder, A. El Alaoui, Y. Ilieva, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and CLAS
Subjects: M008W, Dalitz plot, Analytical chemistry, 01 natural sciences, High Energy Physics - Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare, High Energy Physics - Experiment (hep-ex), CHANNEL, PSEUDOSCALAR RESONANCES, meson: exchange, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment, Monte Carlo, QC, Physics, F(1) 1285, radiative decay, AXIAL-VECTOR, amplitude analysis, K K, Pseudoscalar, Full width at half maximum, ETA-PI+PI-SYSTEM, CENTRAL PP INTERACTIONS, 450 GEV/C, PSEUDOSCALAR, RESONANCES, CLAS, SPIN, COLLISIONS, differential cross section, M008M, branching ratio, f1(1285): photoproduction, missing-mass, Jefferson Lab, Scattering cross-section, Meson, M008.13, FOS: Physical sciences, Socio-culturale, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], eta(1295), Nuclear physics, p: target, 0103 physical sciences, Pi, 010306 general physics, numerical calculations, Pseudovector, M008.1, 010308 nuclear & particles physics, Branching fraction, M008.5, M008.4, M008.3, High Energy Physics::Experiment, experimental results
Abstract: The $f_1(1285)$ meson with mass $1281.0 \pm 0.8$ MeV/$c^2$ and width $18.4 \pm 1.4$ MeV (FWHM) was measured for the first time in photoproduction from a proton target using CLAS at Jefferson Lab. Differential cross sections were obtained via the $\eta\pi^{+}\pi^{-}$, $K^+\bar{K}^0\pi^-$, and $K^-K^0\pi^+$ decay channels from threshold up to a center-of-mass energy of 2.8 GeV. The mass, width, and an amplitude analysis of the $\eta\pi^{+}\pi^{-}$ final-state Dalitz distribution are consistent with the axial-vector $J^P=1^+$ $f_1(1285)$ identity, rather than the pseudoscalar $0^-$ $\eta(1295)$. The production mechanism is more consistent with $s$-channel decay of a high-mass $N^*$ state, and not with $t$-channel meson exchange. Decays to $\eta\pi\pi$ go dominantly via the intermediate $a_0^\pm(980)\pi^\mp$ states, with the branching ratio $\Gamma(a_0\pi \text{ (no} \bar{K} K\text{)}) / \Gamma(\eta\pi\pi \text{(all)}) = 0.74\pm0.09$. The branching ratios $\Gamma(K \bar{K} \pi)/\Gamma(\eta\pi\pi) = 0.216\pm0.033$ and $\Gamma(\gamma\rho^0)/\Gamma(\eta\pi\pi) = 0.047\pm0.018$ were also obtained. The first is in agreement with previous data for the $f_1(1285)$, while the latter is lower than the world average., Comment: 26 pages, 16 figures, Reference added, submitted to Physical Review C
Published: 2016

41. First measurement of the helicity asymmetry E in η photoproduction on the proton

Author: K. A. Griffioen, K. Livingston, B. McKinnon, H. Hakobyan, C. Hanretty, S. Strauch, Latifa Elouadrhiri, C. A. Meyer, G. V. Fedotov, E. De Sanctis, I. Bedlinskiy, S. Chandavar, L. Colaneri, J. Brock, K. P. Adhikari, E. Golovatch, R. Dupre, D. I. Sober, M. C. Kunkel, V. Batourine, M. L. Seely, I. Zonta, Iu. Skorodumina, X. Wei, V. Crede, S. Pisano, Victor Mokeev, I. I. Strakovsky, E. Voutier, F. Sabatié, M. Ripani, D. I. Glazier, H. Egiyan, M. Ungaro, A. Deur, R. A. Montgomery, P. Stoler, Barry Ritchie, A. Simonyan, I. Senderovich, P. Lenisa, Z. W. Zhao, R. De Vita, Diane Schott, W. K. Brooks, A. El Alaoui, Y. Ilieva, K. Hicks, H. S. Jo, K. L. Giovanetti, Gerard Gilfoyle, K. Joo, C. D. Keith, Nicholas Zachariou, K. Park, N. K. Walford, D. G. Ireland, L. Guo, D. G. Jenkins, H. Jiang, Volker D. Burkert, A. S. Biselli, Sylvester Joosten, Michael Dugger, I. J. D. MacGregor, S. Anefalos Pereira, V. P. Kubarovsky, R. A. Badui, S. Park, N. Dashyan, A. Filippi, F. X. Girod, O. Pogorelko, S. M. Hughes, J. Zhang, W. Phelps, P. Nadel-Turonski, M. Khandaker, O. Cortes, W. Gohn, A. Celentano, R. W. Gothe, Ye Tian, Dustin Keller, Friedrich Klein, S. Boiarinov, D. G. Meekins, A. D'Angelo, J. W. Price, C. Djalali, Michael Wood, K. Hafidi, D. Rönchen, E. Seder, M. Contalbrigo, P. Mattione, P. Peng, L. El Fassi, C. Munoz Camacho, J. T. Goetz, R. Tucker, H. Voskanyan, P. L. Cole, E. Pasyuk, Z. Akbar, Lorenzo Zana, J. P. Ball, Y. Prok, P. Roy, D. Adikaram, M. Guidal, D. S. Carman, A. Rizzo, S. Niccolai, C. Salgado, G. D. Smith, M. Holtrop, A. Movsisyan, M. Battaglieri, S. Fegan, A. Kim, G. Charles, T. Mineeva, B. Morrison, V. Sytnik, P. Eugenio, B. S. Ishkhanov, R. A. Schumacher, P. Collins, B. Garillon, Michael Döring, D. Ho, S. Stepanyan, A. Fradi, H. Y. Lu, Andrew Puckett, Nikolaos Sparveris, I. Niculescu, J. A. Fleming, L. A. Net, C. Carlin, G. Rosner, M. Osipenko, Y. Ghandilyan, G. Khachatryan, W. J. Briscoe, G. Niculescu, M. Hattawy, N. A. Baltzell, Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), CLAS Collaboration, and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
Subjects: Particle physics, Nuclear and High Energy Physics, Meson, media_common.quotation_subject, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Asymmetry, NO, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, 0103 physical sciences, Eta photoproduction, ddc:530, Helicity asymmetry, Polarization observable, 010306 general physics, Nuclear Experiment, QC, media_common, Physics, Quantitative Biology::Biomolecules, 010308 nuclear & particles physics, Bremsstrahlung, Resonance, Observable, Helicity, lcsh:QC1-999, Baryon, Physics::Accelerator Physics, High Energy Physics::Experiment, Nucleon, lcsh:Physics
Abstract: Results are presented for the first measurement of the double-polarization helicity asymmetry E for the η photoproduction reaction γp→ηp. Data were obtained using the FROzen Spin Target (FROST) with the CLAS spectrometer in Hall B at Jefferson Lab, covering a range of center-of-mass energy W from threshold to 2.15 GeV and a large range in center-of-mass polar angle. As an initial application of these data, the results have been incorporated into the Jülich–Bonn model to examine the case for the existence of a narrow N⁎ resonance between 1.66 and 1.70 GeV. The addition of these data to the world database results in marked changes in the predictions for the E observable from that model. Further comparison with several theoretical approaches indicates these data will significantly enhance our understanding of nucleon resonances. Keywords: Eta photoproduction, Polarization observable, Helicity asymmetry
Published: 2016

42. Evidence for the onset of color transparency in ρ0 electroproduction off nuclei

Author: G. Niculescu, S. Tkachenko, R. Dupre, M. Battaglieri, L. Guo, P. Khetarpal, R. De Vita, Paolo Rossi, C. Djalali, G. Ricco, Martin K. Mayer, S. Anefalos Pereira, G. E. Dodge, H. Y. Lu, F. X. Girod, V. Mokeev, Barry Ritchie, P. E. Reimer, B. Vernarsky, J. W. Price, V. Kuznetsov, M. S. Saini, E. Voutier, S. Procureur, F. Sabatié, A. Kim, B. Zhao, I. Niculescu, D. G. Ireland, Friedrich Klein, Brian Raue, V. Crede, W. Tang, M. Ripani, K. A. Griffioen, Michael Vineyard, E. De Sanctis, M. Aghasyan, D. I. Sober, J. T. Goetz, W. Gohn, T. Mineeva, D. Schott, P. Nadel-Turonski, M. Osipenko, Y. Mao, V. P. Kubarovsky, S. Niccolai, C. E. Hyde, S. S. Jawalkar, J. Arrington, P. Stoler, Latifa Elouadrhiri, C. A. Meyer, B. Dey, I. J. D. MacGregor, E. Munevar, B. S. Ishkhanov, S. E. Kuhn, C. Hanretty, K. Hicks, G. V. Fedotov, H. Avakian, E. L. Isupov, K. P. Adhikari, A. Celentano, R. W. Gothe, A. Deur, D. P. Weygand, Elton Smith, George Davey Smith, D. J. Tedeschi, H. Voskanyan, R. A. Schumacher, P. Eugenio, M. Taiuti, M. Anghinolfi, W. J. Briscoe, E. Pasyuk, W. K. Brooks, I. Bedlinskiy, H. Seraydaryan, Lorenzo Zana, S. Park, Y. G. Sharabian, A. D'Angelo, H. Hakobyan, S. Bültmann, X. Zheng, A. I. Ostrovidov, K. Park, M. Contalbrigo, R. J. Holt, C. E. Taylor, S. Stepanyan, C. Salgado, Avraham Klein, L. El Fassi, A. Ni, E. Golovatch, M. Ungaro, J. McAndrew, Z. W. Zhao, Michael Wood, Volker D. Burkert, K. Hafidi, A. S. Biselli, B. McKinnon, D. Branford, M. Mirazita, E. Phelps, J. M. Laget, S. S. Stepanyan, N. Gevorgyan, V. Batourine, N. Markov, D. Keller, Sergey Kuleshov, M. Khandaker, Hovanes Egiyan, M. J. Amaryan, R. Paremuzyan, H. Moutarde, K. L. Giovanetti, Larry Weinstein, Gerard Gilfoyle, D. Doughty, D. Heddle, D. Sokhan, D. Adikaram, M. Guidal, B. Mustapha, M. Holtrop, A. Daniel, Luciano Pappalardo, G. Rosner, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, D. Rimal, B. Moreno, R. Dickson, P. L. Cole, D. Protopopescu, S. Pozdniakov, M. Garçon, S. Chandavar, S. Strauch, D. P. Watts, M. Y. Gabrielyan, D. S. Carman, N. Dashyan, H. Baghdasaryan, S. Fegan, C. Bookwalter, and W. Kim
Subjects: Elastic scattering, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Hadron, Virtual particle, Electron, 01 natural sciences, Coherence length, Nuclear physics, Color model, Deuterium, Nuclear transparency, 0103 physical sciences, Nuclear Experiment, 010306 general physics
Abstract: We have measured the nuclear transparency of the incoherent diffractive A(e,e′ρ0) process in 12C and 56Fe targets relative to 2H using a 5 GeV electron beam. The nuclear transparency, the ratio of the produced ρ0ʼs on a nucleus relative to deuterium, which is sensitive to ρA interaction, was studied as function of the coherence length (lc), a lifetime of the hadronic fluctuation of the virtual photon, and the four-momentum transfer squared (Q2). While the transparency for both 12C and 56Fe showed no lc dependence, a significant Q2 dependence was measured, which is consistent with calculations that included the color transparency effects.
Published: 2012

43. Precise measurements of beam spin asymmetries in semi-inclusive π0 production

Author: J. McAndrew, E. De Sanctis, E. Voutier, Michael Wood, K. Hafidi, Y. Prok, M. Aghasyan, D. I. Sober, S. Strauch, S. S. Stepanyan, D. P. Watts, R. Dupre, P. Eugenio, H. Egiyan, D. Keller, N. D. Kvaltine, F. Sabatié, M. Battaglieri, W. Gohn, M. Taiuti, S. Tkachenko, L. Guo, M. Khandaker, G. E. Dodge, H. Y. Lu, M. Y. Gabrielyan, D. Adikaram, M. Guidal, H. Avakian, M. Anghinolfi, E. Munevar, M. Holtrop, R. De Vita, Victor Mokeev, H. Seraydaryan, G. Rosner, C. E. Taylor, I. Niculescu, N. Guler, M. Ungaro, Y. G. Sharabian, A. Daniel, P. Nadel-Turonski, Luciano Pappalardo, W. J. Briscoe, V. Crede, S. Anefalos Pereira, D. Schott, J. P. Ball, S. Chandavar, D. S. Carman, A. M. Micherdzinska, E. Pasyuk, V. Kuznetsov, E. Seder, E. Golovatch, A. El Alaoui, H. Voskanyan, Y. Ilieva, A. I. Ostrovidov, K. Park, M. J. Amaryan, E. L. Isupov, Z. W. Zhao, N. Gevorgyan, K. Joo, George Davey Smith, D. G. Ireland, R. A. Schumacher, A. Ni, Sergey Kuleshov, S. E. Kuhn, S. Procureur, L. Graham, C. Djalali, V. P. Kubarovsky, B. McKinnon, C. E. Hyde, O. Pogorelko, Volker D. Burkert, A. S. Biselli, S. Bültmann, S. Park, B. Guegan, R. W. Gothe, Lorenzo Zana, S. Stepanyan, S. Fegan, P. Rossi, D. Branford, H. S. Jo, K. L. Giovanetti, Avraham Klein, M. Mirazita, I. I. Strakovsky, P. Khetarpal, C. Salgado, A. Fradi, S. Niccolai, A. Deur, W. Kim, Larry Weinstein, V. Batourine, Martin K. Mayer, P. L. Cole, N. Dashyan, G. Niculescu, H. Moutarde, B. Moreno, M. S. Saini, P. Stoler, K. Livingston, D. Doughty, H. Baghdasaryan, Gerard Gilfoyle, M. Contalbrigo, R. Dickson, Jie Zhang, G. Ricco, I. Bedlinskiy, N. Markov, B. Dey, R. Paremuzyan, M. Paolone, Friedrich Klein, S. Pisano, D. Protopopescu, Brian Raue, S. Pozdniakov, M. Garçon, K. Hicks, A. Kim, D. Rimal, W. Tang, M. Osipenko, B. Zhao, S. S. Jawalkar, I. J. D. MacGregor, D. Hasch, E. Phelps, D. G. Jenkins, F. X. Girod, A. DʼAngelo, J. W. Price, M. Ripani, C. Hanretty, J. T. Goetz, R. P. Bennett, Latifa Elouadrhiri, C. A. Meyer, G. V. Fedotov, D. P. Weygand, K. A. Griffioen, P. Collins, Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)
Subjects: Nuclear and High Energy Physics, Angular momentum, Particle physics, DEEP-INELASTIC SCATTERING, FINAL-STATE INTERACTIONS, PION ELECTROPRODUCTION, PARTON DISTRIBUTIONS, DRELL-YAN, LEPTOPRODUCTION, DEPENDENCE, Meson, media_common.quotation_subject, Nuclear Theory, Inelastic scattering, 01 natural sciences, Asymmetry, Settore FIS/04 - Fisica Nucleare e Subnucleare, High Energy Physics - Experiment, Nuclear physics, Pion, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment, 010306 general physics, QC, media_common, Physics, 010308 nuclear & particles physics, Deep inelastic scattering, Amplitude, Physics::Accelerator Physics, High Energy Physics::Experiment, Lepton
Abstract: We present studies of single-spin asymmetries for neutral pion electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV polarized electrons from an unpolarized hydrogen target, using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. A substantial $\sin \phi_h$ amplitude has been measured in the distribution of the cross section asymmetry as a function of the azimuthal angle $\phi_h$ of the produced neutral pion. The dependence of this amplitude on Bjorken $x$ and on the pion transverse momentum is extracted with significantly higher precision than previous data and is compared to model calculations., Comment: to be submitted PLB
Published: 2011

44. Differential cross section of γn→K+Σ− on bound neutrons with incident photons from 1.1 to 3.6 GeV

Author: A. I. Ostrovidov, K. Park, M. E. McCracken, D. G. Ireland, Michael Dugger, Volker D. Burkert, A. S. Biselli, V. P. Kubarovsky, Lorenzo Zana, Sergey Kuleshov, H. S. Jo, C. Salgado, K. A. Griffioen, O. Pogorelko, D. Protopopescu, L. Guo, P. Nadel-Turonski, S. Fegan, R. De Vita, M. Osipenko, S. S. Stepanyan, S. Pozdniakov, W. Gohn, S. Procureur, C. Bookwalter, S. Anefalos Pereira, K. Mikhailov, F. Sabatié, M. Guidal, S. Dhamija, V. Crede, N. Dashyan, W. J. Briscoe, E. Pasyuk, Y. Perrin, T. Mineeva, R. W. Gothe, E. De Sanctis, S. L. Careccia, R. Dupre, M. Holtrop, A. Daniel, Gerard Gilfoyle, G. Ricco, M. Aghasyan, P. Eugenio, M. Battaglieri, J. Salamanca, Friedrich Klein, Brian Raue, K. Joo, D. Sokhan, E. Munevar, D. I. Sober, S. Pisano, B. S. Ishkhanov, B. Morrison, G. Gavalian, S. Tkachenko, W. Kim, B. Zhao, H. Baghdasaryan, M. Ripani, P. L. Cole, B. McKinnon, C. Djalali, G. Niculescu, A. El Alaoui, F. X. Girod, Y. Ilieva, K. L. Giovanetti, Michael Wood, D. Branford, P. Collins, D. Keller, M. Mirazita, E. Voutier, P. Khetarpal, G. Rosner, B. L. Berman, A. D'Angelo, S. S. Jawalkar, I. Niculescu, J. P. Ball, Y. Prok, M. Khandaker, C. Hanretty, D. S. Carman, J. W. Price, N. Hassall, R. A. Schumacher, S. Park, V. Mokeev, P. Rossi, T. A. Forest, S. Stepanyan, H. Moutarde, S. Strauch, P. Stoler, D. P. Watts, B. Dey, B. Moreno, K. Hicks, B. Vernarsky, K. Livingston, J. Zhang, R. Dickson, N. Guler, M. Y. Gabrielyan, H. Hakobyan, D. J. Tedeschi, V. Kuznetsov, S. Niccolai, E. Seder, M. Anghinolfi, H. Seraydaryan, Y. G. Sharabian, Martin K. Mayer, M. S. Saini, Barry Ritchie, J. T. Goetz, I. I. Strakovsky, A. Deur, W. K. Brooks, Kei Moriya, C. A. Meyer, K. P. Adhikari, Michael Vineyard, D. P. Weygand, and D. Doughty
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Photon, Meson, 010308 nuclear & particles physics, Hadron, Photon energy, Strangeness, 7. Clean energy, 01 natural sciences, Nuclear physics, Baryon, 0103 physical sciences, High Energy Physics::Experiment, Neutron, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: Differential cross sections of the reaction γd → K+Σ–(p) have been measured with the CLAS detector at Jefferson Lab using incident photons with energies between 1.1 and 3.6 GeV. This is the first complete set of strangeness photoproduction data on the neutron covering a broad angular range. At energies close to threshold and up to Eγ ~ 1.8 GeV, the shape of the angular distribution is suggestive of the presence of s -channel production mechanisms. For Eγ > 1.8 GeV, a clear forward peak appears and becomes more prominent as the photon energy increases, suggesting contributions from t-channel production mechanisms. Furthermore, these data can be used to constrain future analysis of this reaction.
Published: 2010

45. The extraction of ϕ–N total cross section from d(γ,pK+K−)n

Author: K. Livingston, P. Eugenio, R. Dickson, M. Taiuti, D. Doughty, S. Park, D. Heddle, M. Battaglieri, R. A. Schumacher, S. Stepanyan, Avraham Klein, Michael Vineyard, S. Fegan, K. A. Griffioen, P. Collins, Y. Ilieva, H. Hakobyan, C. E. Hyde, C. Bookwalter, G. E. Dodge, H. Y. Lu, D. G. Ireland, W. Xu, V. Crede, Marco Ripani, F. Sabatié, R. G. Fersch, I. Niculescu, D. J. Tedeschi, M. J. Amaryan, D. Schott, P. L. Cole, Elton Smith, E. L. Isupov, M. E. McCracken, N. Dashyan, I. Bedlinskiy, Gerard Gilfoyle, V. P. Kubarovsky, Michael L. Williams, Tsutomu Mibe, N. Hassall, M. Bellis, S. L. Careccia, D. Sokhan, O. Pogorelko, C. Djalali, Z. W. Zhao, V. Kuznetsov, W. Gohn, A. D'Angelo, H. Baghdasaryan, M. Anghinolfi, Paolo Rossi, K. Hicks, D. Protopopescu, F. X. Girod, Sergey Kuleshov, K. L. Giovanetti, B. McKinnon, I. I. Strakovsky, Lorenzo Zana, S. Pozdniakov, Larry Weinstein, H. Seraydaryan, C. Hanretty, E. Wolin, Friedrich Klein, S. Niccolai, G. Rosner, W. J. Briscoe, Giovanni Ricco, R. Nasseripour, A. Fradi, E. Pasyuk, D. Keller, D. Branford, Brian Raue, J. W. Price, W. Chen, Y. G. Sharabian, J. P. Ball, J. R. Johnstone, L. Guo, C. Salgado, J. M. Laget, A. Deur, Xin Qian, D. S. Carman, Haiyan Gao, M. Ungaro, M. Guidal, M. Khandaker, V. Batourine, S. Tkachenko, S. Pisano, W. K. Brooks, S. Procureur, Martin K. Mayer, K. Joo, B. Zhao, M. S. Saini, A. I. Ostrovidov, K. Park, J. T. Goetz, M. Mirazita, M. Holtrop, A. Daniel, B. Morrison, K. Kramer, Michael Wood, K. Hafidi, Volker D. Burkert, A. S. Biselli, Kei Moriya, C. A. Meyer, J. Zhang, P. Nadel-Turonski, S. S. Jawalkar, E. Golovatch, R. Dupre, G. V. Fedotov, S. Dhamija, R. W. Gothe, S. Strauch, D. P. Watts, K. P. Adhikari, M. Y. Gabrielyan, D. P. Weygand, Barry Ritchie, B. Dey, M. Osipenko, D. Martinez, V. Mokeev, W. Kim, G. Niculescu, P. Khetarpal, C. S. Nepali, R. De Vita, T. Mineeva, S. Anefalos Pereira, E. De Sanctis, D. I. Sober, E. Munevar, B. S. Ishkhanov, and M. R. Niroula
Subjects: Baryon, Nuclear reaction, Physics, Nuclear and High Energy Physics, Cross section (physics), Meson, Deuterium, Proton, Hadron, Analytical chemistry, Atomic physics, Nucleon
Abstract: We report on the first measurement of the differential cross section of ϕ-meson photoproduction for the d ( γ , p K + K − ) n exclusive reaction channel. The experiment was performed using a tagged-photon beam and the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. A combined analysis using data from the d ( γ , p K + K − ) n channel and those from a previous publication on coherent ϕ production on the deuteron has been carried out to extract the ϕ − N total cross section, σ ϕ N . The extracted ϕ − N total cross section favors a value above 20 mb. This value is larger than the value extracted using vector-meson dominance models for ϕ photoproduction on the proton.
Published: 2009

46. Moments of the spin structure functions g1p and g1d for 0.05<Q2<3.0 GeV2

Author: R. A. Schumacher, G. V. O'Rielly, C. D. Keith, Cynthia Marie Hadjidakis, Z. W. Zhao, Chaden Djalali, D. G. Jenkins, Michael Dugger, S. Tkachenko, H. O. Funsten, A. I. Ostrovidov, A. C S Lima, S. Bültmann, L. Morand, M. R. Niroula, T. A. Forest, D. G. Ireland, G. Asryan, Volker D. Burkert, A. S. Biselli, J. Pierce, Elton Smith, M. J. Amaryan, M. MacCormick, O. P. Dzyubak, R. A. Niyazov, I. Hleiqawi, S. L. Careccia, Larry Weinstein, Avraham Klein, E. Golovatch, H. G. Juengst, K. Moriya, Daniel S. Carman, J. Kuhn, Philip L. Cole, S. McAleer, H. Hakobyan, S. Anefalos Pereira, P. D. Rubin, L. Blaszczyk, P. Corvisiero, Y. G. Sharabian, A. Fradi, L. Cheng, G. Audit, A.V. Stavinsky, C. E. Hyde-Wright, F. Sabatié, Nikolay Shvedunov, D. Heddle, P. Stoler, Friedrich Klein, J. P. Cummings, R. De Vita, N. Markov, V. Sapunenko, C. Salgado, Dinko Pocanic, L. Elouadrhiri, N. Kalantarians, S. Stepanyan, K. S. Egiyan, R. C. Minehart, C. A. Meyer, J. Ball, M. Taiuti, S. E. Kuhn, I. I. Strakovsky, M. Bektasoglu, M. Kossov, K. Mikhailov, K.H. Hicks, R. J. Feuerbach, G. V. Fedotov, M. Nozar, A. Deur, I. Popa, V. Crede, J. W. Price, Shifeng Chen, M. Anghinolfi, Laird Kramer, D. P. Watts, H. Egiyan, G. Gavalian, John A. Mueller, L. Casey, B. L. Berman, P. Mattione, B. B. Niczyporuk, G. Rosner, N. Benmouna, N. Pivnyuk, Kwangsoo Kim, J. T. Goetz, M. Mirazita, G. Riccardi, J. R. Calarco, R. A. Miskimen, B. A. Raue, B. McKinnon, W. J. Briscoe, L. M. Qin, R. G. Fersh, P. Eugenio, J. Langheinrich, C. Butuceanu, C. Hanretty, S. S. Stepanyan, E. Pasyuk, S. A. Philips, M. Ripani, G. Ricco, S. A. Morrow, C. Paterson, Y. Ilieva, Michael Vineyard, Victor Mokeev, M. Klusman, B. M. Preedom, D. Branford, P. Collins, B. Moreno, J. R. Johnstone, Lorenzo Zana, J. P. Santoro, Tsutomu Mibe, Gerald Feldman, J. M. Laget, L. Todor, D. Protopopescu, K. L. Giovanetti, S. V. Kuleshov, C. Marchand, S. Pozdniakov, M. Garçon, M. L. Seely, Ji Li, D. J. Tedeschi, G. E. Dodge, H. Y. Lu, J. Lachniet, I. Bedlinskiy, Marco A. Huertas, A. Tkabladze, M. D. Mestayer, E. L. Isupov, P. V. Degtyarenko, D. Rowntree, K. Livingston, Michael L. Williams, M. Holtrop, R. Suleiman, V. Kuznetsov, D. S. Dale, J. Zhang, S. Boiarinov, D. I. Sober, Gerard Gilfoyle, F. X. Girod, G. S. Mutchler, N. A. Baltzell, I. Niculescu, D. Sokhan, J. Salamanca, K. A. Griffioen, D. Lawrence, M. Guillo, N. Guler, R. De Masi, L. El Fassi, J. W C McNabb, Sylvain Bouchigny, H. Denizli, M. Guidal, M. Battaglieri, J. Hardie, S. Strauch, J. D. Kellie, Z. Krahn, R. Nasseripour, S. Barrow, P. Rossi, R. Dickson, N. Baillie, D. Doughty, V. Gyurjyan, R. Bradford, K. Lukashin, B. E. Stokes, G. S. Adams, H. Bagdasaryan, P. Nadel-Turonski, A. V. Skabelin, K. Joo, A. Cazes, S. Procureur, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, L. Guo, M. Ungaro, D. P. Weygand, E. Wolin, N. Hassall, M. Bellis, D. G. Crabb, J. Yun, D. Cords, P. Bosted, A. Yegneswaran, N. Dashyan, Y. Prok, Barry Ritchie, E. De Sanctis, H. S. Jo, S. Niccolai, R. Fatemi, A. V. Vlassov, P. Coltharp, R. W. Gothe, M. M. Ito, K. Y. Kim, M. Osipenko, K. Beard, L. C. Smith, E. Munevar, Kalvir S. Dhuga, B. S. Ishkhanov, O. Pogorelko, M. Khandaker, B. Zhao, F. W. Hersman, W. Kim, G. Niculescu, N. Gevorgyan, L. C. Dennis, B. E. Bonner, H. Avakian, D. Sharov, S. A. Dytman, W. K. Brooks, K. Park, V. P. Kubarovsky, J. Shaw, Michael Wood, K. Hafidi, and V. S. Serov
Subjects: Physics, Nuclear and High Energy Physics, Chiral perturbation theory, Heavy baryon chiral perturbation theory, Proton, 010308 nuclear & particles physics, Nuclear Theory, Hadron, 01 natural sciences, Baryon, Nuclear physics, Polarizability, 0103 physical sciences, Sum rule in quantum mechanics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: The spin structure functions g 1 for the proton and the deuteron have been measured over a wide kinematic range in x and Q 2 using 1.6 and 5.7 GeV longitudinally polarized electrons incident upon polarized NH3 and ND3 targets at Jefferson Lab. Scattered electrons were detected in the CEBAF Large Acceptance Spectrometer, for 0.05 Q 2 5 GeV 2 and W 3 GeV . The first moments of g 1 for the proton and deuteron are presented – both have a negative slope at low Q 2 , as predicted by the extended Gerasimov–Drell–Hearn sum rule. The first extraction of the generalized forward spin polarizability of the proton γ 0 p is also reported. This quantity shows strong Q 2 dependence at low Q 2 . Our analysis of the Q 2 evolution of the first moment of g 1 shows agreement in leading order with Heavy Baryon Chiral Perturbation Theory. However, a significant discrepancy is observed between the γ 0 p data and Chiral Perturbation calculations for γ 0 p , even at the lowest Q 2 .
Published: 2009

47. Exclusive ρ0 electroproduction on the proton at CLAS

Author: J. Langheinrich, S. S. Stepanyan, E. Pasyuk, S. A. Philips, N. Dashyan, V. Sapunenko, G. Ricco, Alexei V. Klimenko, N. A. Baltzell, C. Salgado, Dinko Pocanic, Barry Ritchie, H. Denizli, A. V. Skabelin, K. A. Griffioen, B. Zhao, V. Gyurjyan, A. I. Ostrovidov, R. Fatemi, K. Park, S. E. Kuhn, Latifa Elouadrhiri, R. C. Minehart, Kei Moriya, C. A. Meyer, H. G. Juengst, B. E. Stokes, G. S. Adams, G. V. Fedotov, V. P. Kubarovsky, J. Zhang, P. Eugenio, K. P. Adhikari, A. V. Vlassov, D. P. Weygand, G. E. Dodge, H. Y. Lu, M. J. Amaryan, G. V. O'Rielly, S. Niccolai, Z. W. Zhao, V. Mokeev, Y. Ilieva, Ji Li, D. G. Jenkins, C. Tur, Gerard Gilfoyle, Elton Smith, H. Hakobyan, A.V. Stavinsky, J. D. Kellie, M. Guidal, M. MacCormick, I. Hleiqawi, S. L. Careccia, R. De Vita, Friedrich Klein, Brian Raue, P. V. Degtyarenko, M. D. Mestayer, J. P. Didelez, R. Nasseripour, L. Todor, F. W. Hersman, P. Coltharp, E. L. Isupov, J. P. Cummings, W. Gohn, S. A. Morrow, S. McAleer, M. Anghinolfi, P. Nadel-Turonski, D. Sokhan, D. Protopopescu, D. J. Tedeschi, M. Holtrop, Michael L. Williams, P. Collins, K. L. Giovanetti, I. Niculescu, F. X. Girod, L. Blaszczyk, B. Carnahan, James Mueller, D. Lawrence, R. G. Fersch, R. A. Miskimen, B. McKinnon, S. Pozdniakov, M. Garçon, J. J. Melone, M. M. Ito, S. Boiarinov, Larry Weinstein, L. Zana, P. D. Rubin, R. De Masi, D. Keller, I. Bedlinskiy, B. M. Preedom, S. Anefalos Pereira, D. Schott, Y. G. Sharabian, R. A. Schumacher, P. L. Cole, M. Yurov, M. Taiuti, S. Mehrabyan, D. Branford, L. C. Smith, E. Munevar, G. S. Mutchler, B. S. Ishkhanov, Michael Wood, K. Hafidi, L. Graham, M. Kossov, M. E. McCracken, C. I O Gordon, J. M. Laget, V. Kuznetsov, J. Kuhn, E. Hourany, M. Khandaker, V. S. Serov, L. C. Dennis, B. E. Bonner, J. W. Price, Tsutomu Mibe, S. Bültmann, G. Audit, Shifeng Chen, C. Bookwalter, N. Gevorgyan, M. Osipenko, C. E. Hyde-Wright, J. P. Santoro, H. S. Jo, H. Avakian, L. Morand, I. Popa, D. Sharov, T. A. Forest, G. Riccardi, M. R. Niroula, E. De Sanctis, O. Pogorelko, S. Stepanyan, P. Mattione, C. Butuceanu, M. S. Saini, D. Doughty, J. Pierce, M. Ripani, B. L. Berman, Avraham Klein, L. M. Qin, M. Aghasyan, E. Wolin, Sergey Kuleshov, W. J. Briscoe, D. Heddle, J. T. Goetz, D. I. Sober, Kalvir S. Dhuga, M. Bektasoglu, S. A. Dytman, S. Dhamija, M. Nozar, E. Polli, M. Mirazita, C. Paterson, J. P. Ball, R. W. Gothe, Y. Prok, B. Moreno, W. Kim, J. Hardie, Hall Crannell, D. S. Carman, K. Livingston, G. Rosner, C. Marchand, G. Niculescu, D. S. Dale, N. Baillie, S. Park, Sylvain Bouchigny, J. Lachniet, A. Tkabladze, D. G. Crabb, R. Dickson, Michael Vineyard, D. G. Ireland, V. Crede, J. R. Calarco, P. Khetarpal, N. Guler, J. Salamanca, L. El Fassi, J. W C McNabb, S. Barrow, P. Rossi, L. Casey, H. Bagdasaryan, Volker D. Burkert, A. S. Biselli, B. B. Niczyporuk, N. Pivnyuk, P. Stoler, C. Hanretty, Laird Kramer, J. R. Johnstone, L. Guo, M. Ungaro, A. Fradi, K. Joo, D. Cords, N. Markov, A. Yegneswaran, K. Hicks, M. Battaglieri, R. Bradford, K. S. Egiyan, A. Cazes, S. Procureur, Maryam Moteabbed, Bernhard Mecking, K. V. Dharmawardane, N. Hassall, M. Bellis, K. Mikhailov, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Corvisiero, S. Strauch, D. P. Watts, H. Egiyan, I. I. Strakovsky, A. Deur, W. K. Brooks, R. J. Feuerbach, Cynthia Marie Hadjidakis, M. Guillo, Chaden Djalali, Michael Dugger, L. Cheng, F. Sabatié, Nikolay Shvedunov, N. Kalantarians, G. Gavalian, S. Tkachenko, and N. Benmouna
Subjects: Quark, Physics, REPRESENTATION, Nuclear and High Energy Physics, Particle physics, Valence (chemistry), Proton, Hadron, Parton, VECTOR-MESON ELECTROPRODUCTION, Approx, PHOTONS, QCD, EVOLUTION, High Energy Physics - Experiment, Regge theory, Nuclear physics, Scattering amplitude, GENERALIZED PARTON DISTRIBUTIONS, VIRTUAL COMPTON-SCATTERING, VECTOR-MESON ELECTROPRODUCTION, LARGE MOMENTUM-TRANSFER, DIFFRACTIVE PRODUCTION, PHOTOPRODUCTION, PHOTONS, QCD, REPRESENTATION, EVOLUTION, LARGE MOMENTUM-TRANSFER, GENERALIZED PARTON DISTRIBUTIONS, DIFFRACTIVE PRODUCTION, PHOTOPRODUCTION, Nuclear Experiment, VIRTUAL COMPTON-SCATTERING
Abstract: The $e p\to e^\prime p \rho^0$ reaction has been measured, using the 5.754 GeV electron beam of Jefferson Lab and the CLAS detector. This represents the largest ever set of data for this reaction in the valence region. Integrated and differential cross sections are presented. The $W$, $Q^2$ and $t$ dependences of the cross section are compared to theoretical calculations based on $t$-channel meson-exchange Regge theory on the one hand and on quark handbag diagrams related to Generalized Parton Distributions (GPDs) on the other hand. The Regge approach can describe at the $\approx$ 30% level most of the features of the present data while the two GPD calculations that are presented in this article which succesfully reproduce the high energy data strongly underestimate the present data. The question is then raised whether this discrepancy originates from an incomplete or inexact way of modelling the GPDs or the associated hard scattering amplitude or whether the GPD formalism is simply inapplicable in this region due to higher-twists contributions, incalculable at present., Comment: 29 pages, 29 figures
Published: 2008

48. BoNus: Development and use of a radial TPC using cylindrical GEMs

Author: G. E. Dodge, N. Kalantarians, Volker D. Burkert, C.P. Jayalath, I. Niculescu, C. E. Keppel, K. A. Griffioen, R. G. Fersch, N. Baillie, J. Evans, M. Ispiryan, S. Bueltmann, M. E. Christy, G. Niculescu, P. Bradshaw, K. L. Giovanetti, Dipangkar Dutta, V. Tvaskis, J. Zhang, Rolf Ent, S. E. Kuhn, S. Tkachenko, and H. C. Fenker
Subjects: Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, Scattering, Detector, Particle detector, Linear particle accelerator, Nuclear physics, Measuring instrument, Neutron, Nuclear Experiment, Nucleon, Instrumentation, Lepton
Abstract: A specialized system of target and detector was developed at Jefferson Lab to provide new access to information about neutron structure from electron–neutron interactions. It allows identification and measurement of spectator protons produced in e - d → e - p s X scattering events. The detector is a radial time-projection chamber optimized for the acceptance of low-momentum protons. Gas gain is provided by three cascaded curved Gas Electron Multipliers (GEMs), the first application of GEMs in any configuration other than flat. This article provides details about the development and construction of the detector, its performance, and the analysis of the data from the successful running of its first physics experiment.
Published: 2008

49. The Measurement of the Anomalous Magnetic Moment of the Muon at Fermilab

Author: R. Chislett, J. Carroll, D. Cauz, Andrew Smith, M. Lee, A. Anastasi, E. Hazen, M. Eads, G. Pauletta, R. Osofsky, B. Quinn, R. Fatemi, I. Logashenko, S. Baessler, D.A. Sweigart, N. A. Kuchinskiy, M. W. Smith, D. Still, Yannis K. Semertzidis, W. Gohn, K. L. Giovanetti, V. Tishchenko, L. Welty-Rieger, R. Di Stefano, C. Fu, M. Iacovacci, E. Barzi, V. Volnykh, J. F. Ostiguy, D. W. Hertzog, T. Stuttard, V. A. Baranov, C. J. G. Onderwater, Michael Syphers, G. Luo, V. P. Druzhinin, E. Won, P. T. Debevec, C. Yoshikawa, J. Grange, Martin Fertl, Stephen Maxfield, F. Azfar, A. Epps, L Li, P. Winter, C. Johnstone, A. Fioretti, B. Drendel, K. T. Pitts, M R M Warren, L. K. Gibbons, D. Stöckinger, M. Whitley, Donald B. Rubin, M. Rominsky, J. Crnkovic, T. P. Gorringe, T. Walton, C. Ferrari, Z. Meadows, G. Venanzoni, Thomas Teubner, Nicholas A. Pohlman, S. Haciomeroglu, M. Gaisser, M. Wormald, B. Casey, Frederick Gray, H. Freidsam, Marin Karuza, K. R. Lynch, P. Kammel, S. Henry, S.B. Dabagov, A. L. Lyon, C. Schlesier, E. Motuk, Yuri F. Orlov, D. Allspach, N. Rider, T. J. V. Bowcock, B. Abi, N. Kinnaird, D. Babusci, A. Para, R. M. Carey, A. de Gouvea, J. Johnstone, J. P. Miller, S. Lee, A.T. Fienberg, G. Di Sciascio, Y. Kim, H. Schellman, L.P. Alonzi, H Yang, H. Kamal Sayed, B. L. Roberts, Edward J. Swanson, V. N. Duginov, E. Ramberg, E. Frlez, N. S. Froemming, I. Kourbanis, J. Mott, L. Santi, D. Kawall, Giovanni Cantatore, N. V. Khomutov, G. Corradi, D. Flay, C. C. Polly, Nicholas Eggert, S. Marignetti, R. Bjorkquist, S. Kim, Benjamin T. King, D. Moricciani, C. Gabbanini, A. Tewlsey-Booth, V. Krylov, Yu. M. Shatunov, Andre Frankenthal, S. Leo, M. E. Convery, S. Mastroianni, A. Chapelain, A. Palladino, Andrzej Wolski, H. Nguyen, B. Kiburg, Alexander Mikhailichenko, K. W. Merritt, J. Kaspar, Dinko Pocanic, M. Popovic, M. Lancaster, W. M. Morse, Timothy Chupp, M. McEvoy, Dariush Hampai, X. Ji, M. Shenk, S. Al-Kilani, A. K. Soha, D. A. Tarazona, Klaus-Peter Jungmann, Alejandro Garcia, Logashenko, I., Grange, J., Winter, P., Carey, R. M., Hazen, E., Kinnaird, N., Miller, J. P., Mott, J., Roberts, B. L., Crnkovic, J., Morse, W. M., Sayed, H. Kamal, Tishchenko, V., Druzhinin, V. P., Shatunov, Y. M., Bjorkquist, R., Chapelain, A., Eggert, N., Frankenthal, A., Gibbons, L., Kim, S., Mikhailichenko, A., Orlov, Y., Rider, N., Rubin, D., Sweigart, D., Allspach, D., Barzi, E., Casey, B., Convery, M. E., Drendel, B., Freidsam, H., Johnstone, C., Johnstone, J., Kiburg, B., Kourbanis, I., Lyon, A. L., Merritt, K. W., Morgan, J. P., Nguyen, H., Ostiguy, J. F., Para, A., Polly, C. C., Popovic, M., Ramberg, E., Rominsky, M., Soha, A. K., Still, D., Walton, T., Yoshikawa, C., Jungmann, K., Onderwater, C. J. G., Debevec, P., Leo, S., Pitts, K., Schlesier, C., Anastasi, A., Babusci, D., Corradi, G., Hampai, D., Palladino, A., Venanzoni, G., Dabagov, S., Ferrari, C., Fioretti, A., Gabbanini, C., Di Stefano, R., Marignetti, S., Iacovacci, M., Mastroianni, S., Di Sciascio, G., Moricciani, D., Cantatore, Giovanni, Karuza, M., Giovanetti, K., Baranov, V., Duginov, V., Khomutov, N., Krylov, V., Kuchinskiy, N., Volnykh, V., Gaisser, M., Haciomeroglu, S., Kim, Y., Lee, S., Lee, M., Semertzidis, Y. K., Won, E., Fatemi, R., Gohn, W., Gorringe, T., Bowcock, T., Carroll, J., King, B., Maxfield, S., Smith, A., Teubner, T., Whitley, M., Wormald, M., Wolski, A., Al Kilani, S., Chislett, R., Lancaster, M., Motuk, E., Stuttard, T., Warren, M., Flay, D., Kawall, D., Meadows, Z., Syphers, M., Tarazona, D., Chupp, T., Tewlsey Booth, A., Quinn, B., Eads, M., Epps, A., Luo, G., Mcevoy, M., Pohlman, N., Shenk, M., de Gouvea, A., Welty Rieger, L., Schellman, H., Abi, B., Azfar, F., Henry, S., Gray, F., Fu, C., Ji, X., Li, L., Yang, H., Stockinger, D., Cauz, D., Pauletta, G., Santi, L., Baessler, S., Frlez, E., Pocanic, D., Alonzi, L. P., Fertl, M., Fienberg, A., Froemming, N., Garcia, A., Hertzog, D. W., Kammel, P., Kaspar, J., Osofsky, R., Smith, M., Swanson, E., Lynch, K., Precision Frontier, Ostiguy, J. -F., Cantatore, G., Al-Kilani, S., Tewlsey-Booth, A., Welty-Rieger, L., and Abys, Salvatore
Subjects: Particle physics, magnetic moment, standard model, General Physics and Astronomy, Standard deviation, Standard Model, Muon magnetic moment, Nuclear physics, Physics and Astronomy (all), anomalous magnetic moment, Positron, muon anomaly, muon, Fermilab, Physical and Theoretical Chemistry, instrumentation, Physics, Muon, Anomalous magnetic moment, Standard model, Chemistry (all), Anomalous magnetic dipole moment, Magnetic moment, General Chemistry, Magnetic field, High Energy Physics::Experiment, measurement, muon, magnetic moment, instrumentation, measurement
Abstract: The anomalous magnetic moment of the muon is one of the most precisely measured quantities in experimental particle physics. Its latest measurement at Brookhaven National Laboratory deviates from the Standard Model expectation by approximately 3.5 standard deviations. The goal of the new experiment, E989, now under construction at Fermilab, is a fourfold improvement in precision. Here, we discuss the details of the future measurement and its current status. C 2015 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4917553]
Published: 2015

50. Measurements ofep→e′π+nat1.6<W<2.0 GeV and extraction of nucleon resonance electrocouplings at CLAS

Author: B. S. Ishkhanov, I. Zonta, J. Bono, P. Nadel-Turonski, X. Wei, E. De Sanctis, P. Eugenio, M. Taiuti, K. A. Griffioen, B. Garillon, Z. W. Zhao, C. E. Hyde, A. Filippi, D. Protopopescu, A. Kim, M. Garçon, S. Niccolai, A. Trivedi, Andrew Puckett, J. T. Goetz, F. X. Girod, Michael Paolone, I. I. Strakovsky, V. Crede, L. Guo, R. A. Schumacher, Sergey Kuleshov, M. Khandaker, Alessandro Rizzo, S. Chandavar, W. Tang, G. Charles, A. Deur, M. Osipenko, Latifa Elouadrhiri, Gerard Gilfoyle, Nikolaos Sparveris, M. Battaglieri, W. K. Brooks, A. Simonyan, R. De Vita, R. A. Montgomery, D. Martinez, B. Guegan, H. Hakobyan, C. Hanretty, C. E. Taylor, K. Livingston, N. Dashyan, G. V. Fedotov, S. Strauch, V. Sytnik, E. Golovatch, R. Dupre, Avraham Klein, H. S. Jo, Jie Zhang, S. Anefalos Pereira, V. Mokeev, P. Lenisa, V. P. Kubarovsky, H. S. Joo, H. Y. Lu, W. Phelps, Eugene Pasyuk, Inna Aznauryan, O. Pogorelko, S. M. Hughes, K. P. Adhikari, I. Bedlinskiy, C. Salgado, P. Roy, S. E. Kuhn, P. Peng, Hovanes Egiyan, C. Munoz Camacho, W. Kim, J. A. Fleming, M. Guidal, G. Niculescu, Yordanka Ilieva, H. Avakian, C. Djalali, K. Park, M. Ripani, I. Niculescu, B. McKinnon, P. Rossi, M. J. Amaryan, S. Joosten, G. D. Smith, M. Holtrop, Friedrich Klein, A. El Alaoui, M. Hattawy, Brian Raue, L. Zana, G. Rosner, H. Voskanyan, Nicholas Zachariou, Elton Smith, D. G. Jenkins, W. J. Briscoe, E. Seder, F. Sabatié, P. Stoler, D. P. Watts, S. Procureur, H. Moutarde, Dustin Keller, M. Ungaro, Michael Wood, K. Hicks, Y. G. Sharabian, K. Joo, O. Cortes, E. L. Isupov, Ye Tian, J. W. Price, K. L. Giovanetti, S. Fegan, Iu. Skorodumina, Larry Weinstein, D. Doughty, Y. Prok, D. S. Carman, E. Voutier, M. Contalbrigo, R. A. Badui, A. Celentano, R. W. Gothe, N. K. Walford, J. J. Phillips, I. J. D. MacGregor, A. D'Angelo, L. El Fassi, R. G. Fersch, Diane Schott, P. L. Cole, A. I. Ostrovidov, N. Gevorgyan, D. G. Ireland, H. Jiang, Volker D. Burkert, A. S. Biselli, L. Colaneri, N. Markov, and S. Pisano
Subjects: Physics, Quark, Nuclear and High Energy Physics, Particle physics, Amplitude, Isospin, Quark model, Isobar, Resonance, Invariant mass, Nucleon
Abstract: Differential cross sections of the exclusive process $ep\ensuremath{\rightarrow}{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+}n$ were measured with good precision in the range of the photon virtuality ${Q}^{2}=1.8--4.5$ ${\mathrm{GeV}}^{2}$ and the invariant mass range of the ${\ensuremath{\pi}}^{+}n$ final state $W=1.6--2.0$ GeV using the Continuous Electron Beam Accelerator Facility Large Acceptance Spectrometer. Data were collected with nearly complete coverage in the azimuthal and polar angles of the $n{\ensuremath{\pi}}^{+}$ center-of-mass system. More than 37 000 cross-section points were measured. The contributions of the isospin $I=\frac{1}{2}$ resonances $N(1675){\frac{5}{2}}^{\ensuremath{-}},N(1680){\frac{5}{2}}^{+}$, and $N(1710){\frac{1}{2}}^{+}$ were extracted at different values of ${Q}^{2}$ using a single-channel, energy-dependent resonance amplitude analysis. Two different approaches, the unitary isobar model and the fixed-$t$ dispersion relations, were employed in the analysis. We observe significant strength of the $N(1675){\frac{5}{2}}^{\ensuremath{-}}$ in the ${A}_{1/2}$ amplitude, which is in strong disagreement with quark models that predict both transverse amplitudes to be strongly suppressed. For the $N(1680){\frac{5}{2}}^{+}$ we observe a slow changeover from the dominance of the ${A}_{3/2}$ amplitude at the real photon point $({Q}^{2}=0)$ to a ${Q}^{2}$ where ${A}_{1/2}$ begins to dominate. The scalar amplitude ${S}_{1/2}$ drops rapidly with ${Q}^{2}$ consistent with quark model prediction. For the $N(1710){\frac{1}{2}}^{+}$ resonance our analysis shows significant strength for the ${A}_{1/2}$ amplitude at ${Q}^{2}l2.5$ ${\mathrm{GeV}}^{2}$.
Published: 2015

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