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1. Observation of Beam Spin Asymmetries in the Process ep→e′π+π−X with CLAS12

Author: G. Niculescu, D. Bulumulla, G. Ciullo, Aditya R. Khanal, A. El Alaoui, S. Niccolai, E. L. Isupov, D. S. Carman, F. X. Girod, Nikos Sparveris, K. A. Griffioen, D. G. Ireland, V. I. Mokeev, M. Contalbrigo, V. Crede, Nicholas Zachariou, J. C. Carvajal, Sung-Sik Lee, X. Wei, S. Boiarinov, Andrea Bianconi, P. Lenisa, C. Dilks, Fatiha Benmokhtar, O. Soto, T. B. Hayward, M. Osipenko, R. Paremuzyan, L. Marsicano, Maxime Defurne, B. A. Clary, Latifa Elouadrhiri, A. Movsisyan, N. Tyler, N. Markov, P. L. Cole, N. Dashyan, K. Hicks, I. J. D. MacGregor, S. Strauch, D. I. Glazier, V. P. Kubarovsky, Michael Paolone, Krishna Neupane, H. Hakobyan, F. Bossu, R. Tyson, J. Ritman, Eugene Pasyuk, R. De Vita, D. Marchand, H. S. Jo, H. Avakian, Eric Voutier, L. Lanza, S. Diehl, C. Salgado, A. A. Golubenko, H. Atac, H. Voskanyan, G. Costantini, W. J. Briscoe, L. Barion, S. E. Kuhn, M. Hattawy, A. Vossen, M. Guidal, A. D'Angelo, Dustin Keller, M Ehrhart, P. Naidoo, T. Chetry, D. P. Watts, P. Chatagnon, Y. Prok, U. Shrestha, Michael Wood, F. Sabatié, M. Holtrop, Chaden Djalali, L. El Fassi, V. Mascagna, G. Gavalian, K. Hafidi, A. Filippi, B. A. Raue, Luciano Pappalardo, C. Ayerbe Gayoso, I. Bedlinskiy, Michael Dugger, W. Phelps, G. Angelini, P. Rossi, K. Wei, S. Joosten, S. Fegan, M. Leali, A. Celentano, R. W. Gothe, P. Nadel-Turonski, M. Khachatryan, N. A. Baltzell, K. Livingston, Alessandro Rizzo, Axel Schmidt, T. R. O'Connell, William Brooks, I. I. Strakovsky, F. Hauenstein, A. Kim, L. Venturelli, Jie Zhang, Y. Gotra, Z. E. Meziani, A. Deur, B. Yale, E.P. Segarra, S. Nanda, A. Kripko, T. A. Forest, S. Stepanyan, Y. G. Sharabian, M. Ripani, R. Dupré, M. Bondì, M. Battaglieri, O. Pogorelko, J. Rowley, Volker D. Burkert, A. S. Biselli, A. Hobart, S. Adhikari, B. McKinnon, M. Mirazita, Gerard Gilfoyle, D. Sokhan, M. Arratia, Hovanes Egiyan, C. Munoz Camacho, M. Ungaro, K. Joo, A. Thornton, and W. Kim
Subjects: Quark, Physics, Spectrometer, Proton, Nuclear Theory, General Physics and Astronomy, Deep inelastic scattering, 01 natural sciences, Gluon, Nuclear physics, 0103 physical sciences, Cathode ray, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Beam (structure), Spin-½
Abstract: The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported for the first time. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first observation of a signal that can be used to extract the PDF $e(x)$ in a collinear framework and the helicity-dependent two-pion fragmentation function $G_1^\perp$.
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. An experimental program with high duty-cycle polarized and unpolarized positron beams at Jefferson Lab

Author: Anthony W. Thomas, M. Battaglieri, R. De Vita, D. Marchand, Latifa Elouadrhiri, S. Habet, Hubert Spiesberger, P. Gueye, David Hamilton, Giovanni Salmè, A. Filippi, Pete Markowitz, D. Perera, G. Kalicy, M. Muhoza, N. Kalantarians, H. Atac, M. Khandaker, J. Xie, F. Sabatié, M. Mazouz, Ashot Gasparian, I.P. Fernando, V. Klimenko, T. A. Forest, D. McNulty, Z. E. Meziani, M. Boer, M. McCaughan, A. Asaturyan, J. P. Chen, V. Kozhuharov, S. Stepanyan, Simonetta Liuti, T. Patel, Alberto Accardi, M. Spata, Andrew Puckett, Andreas Metz, Salina Ali, V. Bellini, L. Barion, V. V. Berdnikov, Alexandre Camsonne, P. E. Reimer, M. Shabestari, P. Bisio, Simon Širca, T. Averett, J. Kim, Nikolaos Sparveris, M. Poelker, M. Spreafico, H. F. Ibrahim, Dipangkar Dutta, V. Bertone, Bogdan Wojtsekhowski, Ross Milner, H. Avakian, C. E. Hyde, P. M. King, Marc Vanderhaeghen, A. Somov, Yulia Furletova, Miha Mihovilovič, V. Tadevosyan, P. Sznajder, S. Migliorati, R. S. Beminiwattha, T. Chetry, M. Guidal, Olfred Hansen, T. Kutz, Z. W. Zhao, Barbara Pasquini, Eric Voutier, L. Lanza, M. J. Amaryan, J. R. M. Annand, Fatiha Benmokhtar, T. Gautam, H. Voskanyan, Richard Trotta, Ian L. Pegg, J. F. Owens, W. J. Briscoe, Jingyi Zhou, P. Valente, M. N. H. Rashad, Gordan Krnjaic, P. Lenisa, Elena Santopinto, Joseph Grames, M. Leali, S. Zhamkochyan, M. Caudron, Kai-Thomas Brinkmann, Elton Smith, L. Marsicano, Andrei Afanasev, Luciano Pappalardo, M. Carmignotto, Donal Day, L. Venturelli, Eugene Pasyuk, M. Ungaro, C. Peng, L. Causse, D. Hasell, G. Costantini, Douglas Higinbotham, N. D’Hose, J. Murphy, P. Chatagnon, R. Dupré, M. Bondì, Alexander Ilyichev, Matteo Rinaldi, P. Stoler, Brian Raue, G. N. Grauvogel, R. Santos Estrada, Kondo Gnanvo, K. Price, Q. Liu, S. Diehl, J. Nazeer, Y. G. Sharabian, X. Zheng, S. Niccolai, P. G. Blunden, J. Arrington, Riad Suleiman, J. Erler, S. Joosten, Andrea Bianconi, H.-S. Ko, P. L. Cole, Nilanga Liyanage, I. Albayrak, K. Joo, Jan C. Bernauer, F.-X. Girod, D. Gaskell, A. Kim, Juliette Mammei, A. Italiano, M. Hattawy, C. Ayerbe Gayoso, I. I. Strakovsky, M. Yurov, N. Randazzo, A. Deur, Wally Melnitchouk, H.-G. Zaunick, Michael Kohl, A. D'Angelo, E. Nardi, M. Paolone, C. Zorn, L. El Fassi, B. T. Kriesten, L. Darmé, M. Rathnayake, A. Shahinyan, Jie Zhang, Alessandro Rizzo, D. Flay, W. Xiong, H. Dutrieux, V. Sergeyeva, S. Zhang, E. R. Kinney, Hervé Moutarde, B. Dongwi, Axel Schmidt, Rolf Ent, S. Zhao, Volker D. Burkert, A. S. Tadepalli, A. S. Biselli, Tanja Horn, G. Niculescu, T. Cao, A. Celentano, P. Nadel-Turonski, Ethan Cline, J. Roche, B. Karky, M. Contalbrigo, H. Szumila-Vance, S. Fucini, O. Rondon-Aramayo, M. De Napoli, V. Mascagna, E. Fuchey, L. Cardman, G. Ciullo, Haiyan Gao, Cynthia Keppel, M. Ehrhart, A. Movsisyan, R. Novotny, A. Hobart, Sergio Scopetta, B. McKinnon, S. A. Wood, H. Mkrtchyan, M. Tiefenback, C. Munoz Camacho, Xinzhan Bai, R. Paremuzyan, B. Sawatzky, D. Sokhan, M. Suresh, Markus Diefenthaler, Z. Ye, Mauro Raggi, M. Kerver, Y. Roblin, A. Mkrtchyan, V. P. Kubarovsky, R. Capobianco, T. J. Hague, Dustin Keller, Sonny Mantry, Vladimir Khachatryan, Peter Schweitzer, Michael Wood, Maxime Defurne, 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), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: cross-section, ratio, Photon, parton distributions, elastic scattering, Parton, polarized beam, Electron, Leptons Accelerators, Structure of Nucleons, 7. Clean energy, 01 natural sciences, Dark photon, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), Positron, Economica, electromagnetic form-factors, virtual compton-scattering, generalized, squared 4-momentum transfers, lepton-flavor, violation, electron-proton, parity violation, pair production, Physics, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), Nuclear Experiment, Elastic scattering, Dark sector, JLab, dark photon, Settore FIS/04, lepton: flavor: violation, nucleon: generalized parton distribution, 3. Good health, High Energy Physics - Phenomenology, Elastic and deep inelastic Scattering, Nucleon, Jefferson Lab, Nuclear and High Energy Physics, nucleon: form factor: electromagnetic, FOS: Physical sciences, Socio-culturale, helium: target, Context (language use), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear physics, PE2_2, PE2_1, deeply virtual Compton scattering, 0103 physical sciences, quantum chromodynamics, 010306 general physics, PE2_3, activity report, exchange: two-photon, electroweak interaction, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Ambientale, positron: beam, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], charge: asymmetry, Positron Beams, Physics::Accelerator Physics, proposal, High Energy Physics::Experiment
Abstract: Positron beams, both polarized and unpolarized, are identified as essential ingredients for the experimental programs at the next generation of lepton accelerators. In the context of the hadronic physics program at Jefferson Lab (JLab), positron beams are complementary, even essential, tools for a precise understanding of the electromagnetic structure of nucleons and nuclei, in both the elastic and deep-inelastic regimes. For instance, elastic scattering of polarized and unpolarized electrons and positrons from the nucleon enables a model independent determination of its electromagnetic form factors. Also, the deeply-virtual scattering of polarized and unpolarized electrons and positrons allows unambiguous separation of the different contributions to the cross section of the lepto-production of photons and of lepton-pairs, enabling an accurate determination of the nucleons and nuclei generalized parton distributions, and providing an access to the gravitational form factors. Furthermore, positron beams offer the possibility of alternative tests of the Standard Model of particle physics through the search of a dark photon, the precise measurement of electroweak couplings, and the investigation of charged lepton flavor violation. This document discusses the perspectives of an experimental program with high duty-cycle positron beams at JLab., Comment: 18 pages, 7 figures This version superseeds the previous version which scientific content was decomposed into several more elaborated articles. All of these articles will be collected in the EPJ A Topical Issue about "Positron beam and physics at Jefferson Lab (e+@Jlab)"
Published: 2021

4. 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

5. 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

6. 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

7. 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

8. The CLAS12 Ring Imaging Cherenkov detector

Author: C. Cuevas, Roberto Malaguti, D. Orecchini, M. Mirazita, A. Yegneswaran, Sandro Tomassini, C. Pecar, V. P. Kubarovsky, P. Bonneau, R. A. Montgomery, Roberto Perrino, V. Lucherini, H. Avakian, B. Raydo, Pavel Degtiarenko, C. Dickover, W. J. Briscoe, T. Lemon, A. Movsisyan, G. Angelini, P. Rossi, M. Turisini, M. Contalbrigo, I. Balossino, Thomas P. O'Connor, William Brooks, L. Barion, K. Hafidi, E. Cisbani, A. Kim, Paolo Musico, Fatiha Benmokhtar, Kyungseon Joo, Luciano Pappalardo, and Kevin Bailey
Subjects: Physics, Nuclear and High Energy Physics, Spectrometer, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, business.industry, Detector, Curved mirror, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Ring-imaging Cherenkov detector, Momentum, Optics, Planar, 0103 physical sciences, Radiator (engine cooling), Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, 0210 nano-technology, business, Instrumentation, Cherenkov radiation
Abstract: A ring imaging Cherenkov (RICH) detector has been installed in the CLAS12 spectrometer at Jefferson Laboratory (JLab) to provide kaon identification in the momentum range between 3 GeV/c and 8 GeV/c. The detector adopts a hybrid optics solution with aerogel radiator, light planar and spherical mirrors, and highly segmented photon detectors. We report here on the design, construction, and initial performance of the RICH during the commissioning of the detector and the first physics data taking period.
Published: 2020

9. Measurements of the γvp→p′π+π− cross section with the CLAS detector for 0.4GeV2<Q2<1.0GeV2 and 1.3GeV<W<1.825GeV

Author: Z. W. Zhao, S. Strauch, Whitney Armstrong, M. Battaglieri, K. Park, Volker D. Burkert, H. Hakobyan, R. A. Schumacher, A. S. Biselli, P. Eugenio, T. Mineeva, Barry Ritchie, M. Khandaker, Y. Ilieva, M. Khachatryan, S. Johnston, N. Markov, M. Hattawy, I. Bedlinskiy, Nicholas Zachariou, M. L. Kabir, Maxime Defurne, F. X. Girod, G. Khachatryan, G. Charles, D. G. Ireland, P. Nadel-Turonski, B. A. Clary, Y. Prok, F. Sabatié, X. Wei, R. De Vita, K. Hicks, Michael Paolone, S. Procureur, M. Ungaro, R. A. Montgomery, Sylvester Joosten, M. Osipenko, K. Livingston, J. W. Price, G. Ciullo, J. P. Ball, D. S. Carman, D. Heddle, K. A. Griffioen, I. I. Strakovsky, G. D. Smith, M. Holtrop, S. Niccolai, I. J. D. MacGregor, Jie Zhang, Avraham Klein, Nikos Sparveris, A. Deur, Hovanes Egiyan, C. Munoz Camacho, A. D'Angelo, V. Mokeev, E. De Sanctis, Y. Ghandilyan, N. Dashyan, G. V. Fedotov, A. Celentano, R. W. Gothe, R. Paremuzyan, Taya Chetry, L. Lanza, P. Lenisa, W. K. Brooks, Nicholas M. Harrison, Gerard Gilfoyle, D. I. Sober, M. Ripani, A. Kim, D. Sokhan, G. Gavalian, Y. G. Sharabian, D. G. Jenkins, M. Bashkanov, S. Adhikari, Iu. Skorodumina, B. McKinnon, L. Guo, Sergey Kuleshov, W. Kim, G. Niculescu, E. Golovatch, R. Dupre, L. El Fassi, Alessandro Rizzo, V. Batourine, L. Barion, Friedrich Klein, M. Contalbrigo, N. Tyler, C. Djalali, J. A. Tan, C. Hanretty, H. S. Jo, B. S. Ishkhanov, M. Taiuti, R. G. Fersch, P. L. Cole, C. Salgado, O. Cortes, E. L. Isupov, S. Boiarinov, D. Protopopescu, E. Voutier, I. Balossino, Dustin Keller, Michael Wood, K. Hafidi, H. Avakian, H. Voskanyan, W. J. Briscoe, E. Pasyuk, V. P. Kubarovsky, D. Riser, and O. Pogorelko
Subjects: Physics, Photon, 010308 nuclear & particles physics, Detector, 01 natural sciences, Nuclear physics, Cross section (physics), Reaction model, 0103 physical sciences, High Energy Physics::Experiment, Invariant mass, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: New results on the single-differential and fully integrated cross sections for the process γvp→p′π+π- are presented. The experimental data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the kinematic region of the reaction invariant mass W from 1.3 to 1.825 GeV and the photon virtuality Q2 from 0.4 to 1.0 GeV2. The cross sections were obtained in narrow Q2 bins (0.05 GeV2) with the smallest statistical uncertainties achieved in double-pion electroproduction experiments to date. The results were found to be in agreement with previously available data where they overlap. A preliminary interpretation of the extracted cross sections, which was based on a phenomenological meson-baryon reaction model, revealed substantial relative contributions from nucleon resonances. The data offer promising prospects to improve knowledge on the Q2 evolution of the electrocouplings of most resonances with masses up to ∼1.8 GeV.
Published: 2018

10. 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

11. Measurement of the Q2 Dependence of the Deuteron Spin Structure Function g1 and its Moments at Low Q2 with CLAS

Author: I. Balossino, K. Kovacs, C. E. Hyde, Taya Chetry, P. Lenisa, Friedrich Klein, E. De Sanctis, D. G. Meekins, R. A. Schumacher, R. W. Gothe, L. El Fassi, Latifa Elouadrhiri, Y. Prok, Michael Paolone, L. Lanza, V. Crede, K. Park, C. A. Meyer, C. Munoz Camacho, J. Brock, G. V. Fedotov, J. P. Chen, K. Livingston, V. P. Kubarovsky, X. Zheng, A. D'Angelo, D. Heddle, B. McKinnon, M. Battaglieri, P. L. Cole, V. A. Drozdov, S. Bültmann, Maxime Defurne, G. Khachatryan, H. Avakian, M. Hattawy, J. A. Tan, K. P. Adhikari, N. Markov, M. Mirazita, Martin K. Mayer, H. Kang, K. Hafidi, S. Strauch, K. Joo, J. Pierce, Avraham Klein, K. Hicks, M. J. Amaryan, H. Hakobyan, J. W. Price, P. Bosted, H. S. Jo, W. Kim, M. Khachatryan, W. J. Briscoe, Nikolaos Sparveris, R. De Vita, M. Guidal, G. Niculescu, E. Pasyuk, K. A. Griffioen, G. E. Dodge, N. Dashyan, S. K. Phillips, C. Carlin, R. Paremuzyan, W. Phelps, A. Filippi, G. D. Smith, M. Holtrop, I. Bedlinskiy, M. Osipenko, Y. Ilieva, H. Egiyan, Larry Weinstein, D. Payette, E. L. Isupov, E. Golovatch, R. Dupre, Z. W. Zhao, I. J. D. MacGregor, P. Nadel-Turonski, Nicholas M. Harrison, Gerard Gilfoyle, S. E. Kuhn, F. Thanh Cao, S. Stepanyan, N. Guler, S. Johnston, D. Sokhan, Laura Clark, M. Ungaro, A. I. Ostrovidov, Luciano Pappalardo, E. Long, Sylvester Joosten, D. G. Jenkins, M. Khandaker, B. A. Raue, M. Contalbrigo, D. G. Ireland, Chaden Djalali, X. Wei, T. Shigeyuki, C. D. Keith, G. Rosner, Volker D. Burkert, P. Eugenio, M. Taiuti, S. Choi, T. Mineeva, A. S. Biselli, L. Guo, Y. Ghandilyan, P. Rossi, M. L. Kabir, S. Niccolai, A. El Alaoui, P. Konczykowski, Andrea Celentano, Karl Slifer, C. Salgado, L. Barion, J. Poudel, O. Pogorelko, C. Hanretty, M. Ripani, Z. Akbar, I. I. Strakovsky, A. Simonyan, G. Ciullo, J. P. Ball, D. S. Carman, A. Rizzo, A. Deur, A. Movsisyan, Victor Mokeev, J. Zhang, D. Protopopescu, S. Adhikari, E. Voutier, Y. G. Sharabian, G. Charles, V. Sulkosky, F. Sabatié, David M. Keller, and Iu. Skorodumina
Subjects: Physics, Quantum chromodynamics, Nuclear reaction, Chiral perturbation theory, Magnetic moment, 010308 nuclear & particles physics, General Physics and Astronomy, Spin structure, 01 natural sciences, Nuclear magnetic resonance, Polarizability, 0103 physical sciences, High Energy Physics::Experiment, Invariant mass, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: We measured the g 1 spin structure function of the deuteron at low Q 2 , where QCD can be approximated with chiral perturbation theory ( χ PT ). The data cover the resonance region, up to an invariant mass of W ≈ 1.9 GeV . The generalized Gerasimov-Drell-Hearn sum, the moment Γ d 1 and the spin polarizability γ d 0 are precisely determined down to a minimum Q 2 of 0.02 GeV 2 for the first time, about 2.5 times lower than that of previous data. We compare them to several χ PT calculations and models. These results are the first in a program of benchmark measurements of polarization observables in the χ PT domain.
Published: 2018

12. 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

13. 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

14. 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

15. Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1 GeV2 . II. ep→eπ0p

Author: G. Murdoch, I. Zonta, D. Heddle, G. Hollis, R. A. Schumacher, S. Koirala, F. Sabatié, E. Golovatch, K. A. Griffioen, G. Charles, S. Niccolai, E. De Sanctis, I. Balossino, C. Djalali, Alessandro Rizzo, Frank Klein, G. V. Fedotov, B. Torayev, Dustin Keller, Taya Chetry, D. P. Watts, H. Egiyan, G. Ciullo, J. P. Ball, Y. Prok, T. Mineeva, D. S. Carman, T. A. Forest, D. G. Jenkins, C. Hanretty, G. Rosner, P. Lenisa, S. Stepanyan, L. Elouadrhiri, L. Lanza, Igor Strakovsky, Nikos Sparveris, A. Filippi, X. Wei, K. Hafidi, Y. Ghandilyan, H. Y. Lu, P. Stoler, E. Fanchini, M. Khandaker, A. Deur, Michael Paolone, E. Voutier, I. Bedlinskiy, A. Movsisyan, H. Avakian, D. G. Ireland, P. Bosted, P. Roy, V. Crede, P. Eugenio, M. Taiuti, D. Adikaram, Brian Raue, M. J. Amaryan, M. Osipenko, N. Dashyan, M. Guidal, R. Dupre, M. Battaglieri, F. X. Girod, D. I. Glazier, A. Kim, K. Hicks, G. Niculescu, E. Seder, R. A. Montgomery, H. Voskanyan, S. Bültmann, I. Stankovic, R. De Vita, M. Holtrop, W. J. Briscoe, E. Pasyuk, I. J. D. MacGregor, J. Zhang, Y. G. Sharabian, Iu. Skorodumina, A. Ni, W. Gohn, J. W. Price, Larry Weinstein, W. Kim, William Brooks, M. Ripani, S. Chandavar, S. Strauch, G. Khachatryan, S. Anefalos Pereira, S. Fegan, S. E. Kuhn, Laura Clark, M. Hattawy, L. Guo, M. Ungaro, S. M. Hughes, J. A. Fleming, V. P. Kubarovsky, W. Phelps, O. Cortes, V. Mokeev, E. L. Isupov, O. Pogorelko, A Klei, Ye Tian, P. Rossi, Andrew Puckett, S. Boiarinov, Martin K. Mayer, K. Joo, K. P. Adhikari, M. S. Saini, H. Hakobyan, H. S. Jo, M. Contalbrigo, Z. Akbar, M. E. McCracken, P. Nadel-Turonski, R. A. Badui, George Davey Smith, A. D'Angelo, A. Celentano, R. W. Gothe, L. El Fassi, N. K. Walford, R. G. Fersch, T. Cao, P. L. Cole, Z. W. Zhao, K. Livingston, N. Guler, D. Protopopescu, A. El Alaoui, Nicholas Zachariou, A. I. Ostrovidov, K. Park, B. McKinnon, H. Jiang, M. Mirazita, Volker D. Burkert, A. S. Biselli, C. Munoz Camacho, R. Paremuzyan, Nicholas M. Harrison, Gerard Gilfoyle, D. Sokhan, L. Colaneri, A. Fradi, N. Markov, and S. Pisano
Subjects: Physics, Particle physics, 010308 nuclear & particles physics, Scattering, Resonance, Electron, 01 natural sciences, Nuclear physics, Pion, Amplitude, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, Sign (mathematics), Spin-½
Abstract: Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive pi(0) electroproduction reaction. gamma(*) p -> p pi(0), expanding an analysis of the. gamma(*) p -> n pi(+) reaction from the same experiment. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic ranges covered are 1.1 < W < 3 GeV and 1 < Q(2) < 6 GeV2. Results were obtained for about 5700 bins in W, Q(2), cos(theta(*)), and phi(*). The beam-target asymmetries were found to generally be greater than zero, with relatively modest phi(*) dependence. The target asymmetries exhibit very strong phi(*) dependence, with a change in sign occurring between results at low W and high W, in contrast to pi(+) electroproduction. Reasonable agreement is found with phenomenological fits to previous data for W < 1.6 GeV, but significant differences are seen at higherW. When combined with cross-sectional measurements, as well as pi(+) observables, 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 2.4 GeV.
Published: 2017

16. Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1GeV2 . I. ep→eπ+n

Author: Sylvester Joosten, P. Lenisa, B. McKinnon, I. Zonta, G. Ciullo, C. Djalali, J. P. Ball, Y. Prok, D. S. Carman, M. Mirazita, V. Crede, Nikos Sparveris, X. Wei, M. Osipenko, N. Gevorgyan, V. Batourine, H. Egiyan, R. A. Badui, M. Guidal, S. Niccolai, R. A. Montgomery, S. E. Kuhn, M. Hattawy, Brian Raue, K. A. Griffioen, J. A. Fleming, A. Filippi, M. Holtrop, G. Charles, Gerard Gilfoyle, D. Protopopescu, D. Sokhan, L. Colaneri, A. Fradi, Andrew Puckett, E. Voutier, W. Kim, S. Chandavar, I. Bedlinskiy, P. Eugenio, M. Taiuti, Laura Clark, M. Khandaker, R. W. Gothe, P. Rossi, E. Seder, P. L. Cole, Z. W. Zhao, I. Stankovic, K. Livingston, Yordanka Ilieva, Iu. Skorodumina, S. Pisano, K. Hicks, P. Peng, M. J. Amaryan, L. Lanza, C. Munoz Camacho, M. E. McCracken, S. Strauch, G. Murdoch, S. M. Hughes, P. Nadel-Turonski, M. Ripani, L. A. Net, S. Stepanyan, W. Phelps, C. Gleason, Larry Weinstein, S. Koirala, N. K. Walford, F. X. Girod, A. El Alaoui, I. J. D. MacGregor, Andrea Celentano, B. Torayev, A. I. Ostrovidov, K. Park, M. Contalbrigo, Nicholas Zachariou, C. A. Meyer, D. G. Ireland, H. Jiang, G. V. Fedotov, Volker D. Burkert, A. S. Biselli, H. Hakobyan, M. Battaglieri, H. S. Jo, W. Gohn, Victor Mokeev, L. Elouadrhiri, I. I. Strakovsky, E. Fanchini, A. Deur, J. Zhang, J. W. Price, M. Ungaro, E. Golovatch, R. Dupre, K. Joo, E. L. Isupov, Ye Tian, R. De Vita, S. Anefalos Pereira, E. De Sanctis, R. A. Schumacher, T. A. Forest, N. A. Baltzell, G. Khachatryan, W. J. Briscoe, G. Rosner, Y. Ghandilyan, A. Kim, E. Munevar, B. S. Ishkhanov, George Davey Smith, A. D'Angelo, Frank Klein, L. El Fassi, P. E. Bosted, H. Avakian, H. Voskanyan, S. Bültmann, E. Pasyuk, V. P. Kubarovsky, and O. Pogorelko
Subjects: Physics, Meson, 010308 nuclear & particles physics, Scattering, Form factor (quantum field theory), Resonance, Electron, 01 natural sciences, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon, Spin-½
Abstract: Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π 0 electroproduction reaction γ ∗ p → p π 0 , expanding an analysis of the γ ∗ p → n π + reaction from the same experiment. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic ranges covered are 1.1 < W < 3 GeV and 1 < Q 2 < 6 GeV 2 . Results were obtained for about 5700 bins in W , Q 2 , cos ( θ ∗ ) , and ϕ ∗ . The beam-target asymmetries were found to generally be greater than zero, with relatively modest ϕ ∗ dependence. The target asymmetries exhibit very strong ϕ ∗ dependence, with a change in sign occurring between results at low W and high W , in contrast to π + electroproduction. Reasonable agreement is found with phenomenological fits to previous data for W < 1.6 GeV, but significant differences are seen at higher W . When combined with cross-sectional measurements, as well as π + observables, 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 2.4 GeV.
Published: 2017

17. 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

18. 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

19. Hard exclusive pion electroproduction at backward angles with CLAS

Author: H. Avakian, B. S. Ishkhanov, K. A. Griffioen, H. Voskanyan, R. Paremuzyan, A. El Alaoui, E. L. Isupov, M. Battaglieri, Nicholas Zachariou, M. Ripani, I. Bedlinskiy, C. Salgado, K. Livingston, M. Hattawy, R. Fersch, S. Stepanyan, M. Ungaro, Nicholas M. Harrison, Gerard Gilfoyle, D. Sokhan, Laura Clark, P. Rossi, Maxime Defurne, Friedrich Klein, P. Eugenio, M. Taiuti, M. L. Kabir, G. Charles, F. Sabatié, A. D'Angelo, David M. Keller, L. Guo, D. Heddle, Chaden Djalali, I. J. D. MacGregor, R. W. Gothe, R. A. Schumacher, W. Kim, O. Pogorelko, F. X. Girod, L. Lanza, C. Munoz Camacho, J. W. Price, C. E. Hyde, C. Hanretty, X. Wei, Y. Prok, M. Khachatryan, K. Hicks, J. Ball, K. Hafidi, M. Osipenko, J. Zhang, D. Protopopescu, Latifa Elouadrhiri, R. De Vita, V. Crede, R. A. Montgomery, Nikolaos Sparveris, E. Voutier, S. Strauch, G. V. Fedotov, Y. G. Sharabian, M. Contalbrigo, Victor Mokeev, B. McKinnon, Taya Chetry, M. Khandaker, Iu. Skorodumina, Andrea Celentano, H. Hakobyan, L. El Fassi, M. Mirazita, J. Poudel, J. M. Laget, S. Niccolai, Z. Akbar, S. Johnston, N. Markov, Kirill M. Semenov-Tian-Shansky, I. I. Strakovsky, G. Niculescu, Y. Ilieva, K. P. Adhikari, A. Deur, E. De Sanctis, S. Adhikari, Y. Ghandilyan, A. Filippi, Michael Paolone, E. Golovatch, R. Dupre, P. L. Cole, D. G. Ireland, S. E. Kuhn, G. Ciullo, G. Khachatryan, D. S. Carman, F. Cao, A. Rizzo, M. Guidal, Volker D. Burkert, W. J. Briscoe, A. S. Biselli, E. Pasyuk, N. Dashyan, William Brooks, G. D. Smith, M. Holtrop, L. Barion, N. A. Baltzell, M. Garçon, H. Egiyan, P. Nadel-Turonski, K. Joo, J. A. Tan, D. G. Jenkins, Bernard Pire, W. Phelps, I. Balossino, K. Park, V. P. Kubarovsky, 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), Centre de Physique Théorique [Palaiseau] (CPHT), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Interactions Fondamentales en Physique et en Astrophysique (IFPA), Université de Liège, Thomas Jefferson National Accelerator Facility (Jefferson Lab), Istituto Nazionale di Fisica Nucleare, Sezione di Torino (INFN, Sezione di Torino), Istituto Nazionale di Fisica Nucleare (INFN), University of Ca’ Foscari [Venice, Italy], 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, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Clemson University, Old Dominion University [Norfolk] (ODU), CSIRO Astronomy and Space Science, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Massachusetts Institute of Technology (MIT), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'automatique et de génie des procédés (LAGEP), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS), Politecnico di Torino = Polytechnic of Turin (Polito), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), School of Mechanical Engineering, University of Birmingham [Birmingham], School of Geography, 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), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Université de Lyon-Université de Lyon-École Supérieure Chimie Physique Électronique de Lyon-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Quark, Nuclear and High Energy Physics, Electroproduction, Exclusive single pion, transition distribution amplitudes, Particle physics, Meson, Proton, Nuclear Theory, Hadron, Socio-culturale, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], TDA, 01 natural sciences, Resonance (particle physics), CLAS, Eletroproduction, High Energy Physics - Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), Pion, High Energy Physics - Phenomenology (hep-ph), 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, lcsh:QC1-999, Baryon, High Energy Physics - Phenomenology, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], High Energy Physics::Experiment, Nucleon, lcsh:Physics
Abstract: We report on the first measurement of cross sections for exclusive deeply virtual pion electroproduction off the proton, $e p \to e^\prime n \pi^+$, above the resonance region at backward pion center-of-mass angles. The $\varphi^*_{\pi}$-dependent cross sections were measured, from which we extracted three combinations of structure functions of the proton. Our results are compatible with calculations based on nucleon-to-pion transition distribution amplitudes (TDAs) and shed new light on nucleon structure., Comment: 7 pages, 6figures
Published: 2017
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20. Constraints on spin-dependent parton distributions at large x from global QCD analysis

Author: P. Jimenez-Delgado, Wolodymyr Melnitchouk, and H. Avakian
Subjects: Quantum chromodynamics, Physics, Nuclear and High Energy Physics, Angular momentum, Particle physics, Nuclear Theory, High Energy Physics::Phenomenology, FOS: Physical sciences, Perturbative QCD, Context (language use), Parton, Deep inelastic scattering, lcsh:QC1-999, High Energy Physics - Experiment, Gluon, Nuclear Theory (nucl-th), Momentum, High Energy Physics - Phenomenology, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), High Energy Physics::Experiment, Nuclear Experiment, lcsh:Physics
Abstract: We investigate the behavior of spin-dependent parton distribution functions (PDFs) at large parton momentum fractions x in the context of global QCD analysis. We explore the constraints from existing deep-inelastic scattering data, and from theoretical expectations for the leading x -> 1 behavior based on hard gluon exchange in perturbative QCD. Systematic uncertainties from the dependence of the PDFs on the choice of parametrization are studied by considering functional forms motivated by orbital angular momentum arguments. Finally, we quantify the reduction in the PDF uncertainties that may be expected from future high-x data from Jefferson Lab at 12 GeV., 14 pages, 3 figures, 1 table
Published: 2014

21. 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

22. 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

23. Experimental results on TMDs

Author: Alessandro Bressan, H. Avakian, M. Contalbrigo, Avakian, H., Bressan, Andrea, and Contalbrigo, M.
Subjects: Physics, Quantum chromodynamics, Quark, Particle physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Hadron, TMDs, Nuclear and High Energy Physics, TMDs, Parton, Deep inelastic scattering, 01 natural sciences, Helicity, Nuclear physics, Distribution function, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: QCD factorisation for semi-inclusive deep inelastic scattering (DIS) at low transverse momentum in the current-fragmentation region has been established recently, providing a rigorous basis to study the transverse-momentum-dependent (TMD) distribution and fragmentation functions of partons from semi-inclusive DIS data using different spin-dependent and spin-independent observables. The main focus of the experiments were the measurements of various single- and double-spin asymmetries in hadron electro-production ( $ e p^{\uparrow} \rightarrow ehX$ with unpolarised, longitudinally and transversely polarised targets. The joint use of a longitudinally polarised beam and longitudinally and transversely polarised targets allowed to measure double-spin asymmetries related to leading-twist distribution functions describing the transverse-momentum distribution of longitudinally and transversely polarised quarks in a longitudinally and transversely polarised nucleons (helicity and worm-gear TMDs). The single-spin asymmetries measured with transversely polarised targets, provided access to specific leading-twist parton distribution functions: the transversity, the Sivers function and the so-called “pretzelosity” function. In this review we present the current status and some future measurements of TMDs worldwide.
Published: 2016

24. 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

25. Single and double spin asymmetries for deeply virtual Compton scattering measured with CLAS and a longitudinally polarized proton target

Author: M. Contalbrigo, R. A. Schumacher, P. Bosted, Andrew Puckett, A. Kim, P. Stoler, S. Chandavar, J. P. Ball, Y. Prok, E. Golovatch, I. Zonta, P. Roy, D. Adikaram, M. Guidal, B. S. Ishkhanov, Nikolaos Sparveris, B. Briscoe, K. Hicks, N. Compton, M. Garçon, Iu. Skorodumina, A. Rizzo, X. Wei, S. Joosten, G. D. Smith, M. Holtrop, V. Sytnik, M. Mirazita, P. Nadel-Turonski, A. El Alaoui, O. Cortes, C. D. Keith, Ye Tian, J. J. Phillips, S. Niccolai, D. G. Crabb, Nicholas Zachariou, P. Lenisa, S. Tkachenko, S. Stepanyan, R. Dupre, L. Guo, M. Ripani, D. P. Watts, I. J. D. MacGregor, E. De Sanctis, J. Brock, R. De Vita, S. Fegan, R. W. Gothe, M. Osipenko, William Brooks, J. T. Goetz, Latifa Elouadrhiri, O. Pogorelko, Z. W. Zhao, Diane Schott, C. A. Meyer, M. Ungaro, D. I. Sober, A. I. Ostrovidov, K. Park, Hovanes Egiyan, M. Battaglieri, C. Munoz Camacho, G. V. Fedotov, A. Deur, K. A. Griffioen, V. Crede, D. G. Ireland, W. Phelps, Lorenzo Zana, C. I. Moody, H. Y. Lu, Volker D. Burkert, A. S. Biselli, B. McKinnon, Friedrich Klein, K. P. Adhikari, D. G. Jenkins, C. Hanretty, R. A. Montgomery, L. Colaneri, C. Salgado, G. Charles, H. S. Jo, A. Fradi, S. E. Kuhn, W. Kim, V. Batourine, M. Hattawy, Chaden Djalali, J. A. Fleming, G. Rosner, I. Bedlinskiy, M. Turisini, F. Sabatié, E. Seder, S. Strauch, K. Joo, K. Livingston, W. Gohn, J. W. Price, Y. Ghandilyan, C. Carlin, S. Pisano, Gerard Gilfoyle, S. Anefalos Pereira, M. Mayer, D. S. Carman, D. Sokhan, Andrea Celentano, R. Fersch, Victor Mokeev, H. Avakian, E. Voutier, P. Rossi, J. Zhang, N. K. Walford, X. Jiang, V. P. Kubarovsky, D. G. Meekins, Annalisa D'Angelo, S. M. Hughes, L. El Fassi, Michael Wood, K. Hafidi, P. L. Cole, P. Eugenio, F. X. Girod, S. Procureur, B. Garillon, Y. Ilieva, M. J. Amaryan, M. MacCormick, K. L. Giovanetti, Larry Weinstein, D. Keller, A. Filippi, 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), 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, CLAS Collaboration, 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 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)
Subjects: Quark, Nuclear and High Energy Physics, Particle physics, Photon, Meson, FOS: Physical sciences, Parton, Kinematics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, NO, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), GENERALIZED PARTON DISTRIBUTIONS, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), NUCLEON, 010306 general physics, Nuclear Experiment, Quantum chromodynamics, Physics, 010308 nuclear & particles physics, ELECTROPRODUCTION, MESONS, QCD, Compton scattering, High Energy Physics::Experiment, Nucleon
Abstract: Single-beam, single-target, and double-spin asymmetries for hard exclusive photon production on the proton $\vec{e}\vec{p} \to e' p'\gamma$ are presented. The data were taken at Jefferson Lab using the CLAS detector and a longitudinally polarized ${}^{14}$NH$_3$ target. The three asymmetries were measured in 165 4-dimensional kinematic bins, covering the widest kinematic range ever explored simultaneously for beam and target-polarization observables in the valence quark region. The kinematic dependences of the obtained asymmetries are discussed and compared to the predictions of models of Generalized Parton Distributions. The measurement of three DVCS spin observables at the same kinematic points allows a quasi-model-independent extraction of the imaginary parts of the $H$ and $\tilde{H}$ Compton Form Factors, which give insight into the electric and axial charge distributions of valence quarks in the proton., Comment: 28 pages, 25 figures
Published: 2015

26. Cross Sections for the Exclusive Photon Electroproduction on the Proton and Generalized Parton Distributions

Author: H S, Jo, F X, Girod, H, Avakian, V D, Burkert, M, Garçon, M, Guidal, V, Kubarovsky, S, Niccolai, P, Stoler, K P, Adhikari, D, Adikaram, M J, Amaryan, M D, Anderson, S, Anefalos Pereira, J, Ball, N A, Baltzell, M, Battaglieri, V, Batourine, I, Bedlinskiy, A S, Biselli, S, Boiarinov, W J, Briscoe, W K, Brooks, D S, Carman, A, Celentano, S, Chandavar, G, Charles, L, Colaneri, P L, Cole, N, Compton, M, Contalbrigo, V, Crede, A, D'Angelo, N, Dashyan, R, De Vita, E, De Sanctis, A, Deur, C, Djalali, R, Dupre, A El, Alaoui, L El, Fassi, L, Elouadrhiri, G, Fedotov, S, Fegan, A, Filippi, J A, Fleming, B, Garillon, N, Gevorgyan, Y, Ghandilyan, G P, Gilfoyle, K L, Giovanetti, J T, Goetz, E, Golovatch, R W, Gothe, K A, Griffioen, B, Guegan, N, Guler, L, Guo, K, Hafidi, H, Hakobyan, N, Harrison, M, Hattawy, K, Hicks, N, Hirlinger Saylor, D, Ho, M, Holtrop, S M, Hughes, Y, Ilieva, D G, Ireland, B S, Ishkhanov, D, Jenkins, K, Joo, S, Joosten, D, Keller, G, Khachatryan, M, Khandaker, A, Kim, W, Kim, A, Klein, F J, Klein, S E, Kuhn, S V, Kuleshov, P, Lenisa, K, Livingston, H Y, Lu, I J D, MacGregor, B, McKinnon, Z E, Meziani, M, Mirazita, V, Mokeev, R A, Montgomery, H, Moutarde, A, Movsisyan, E, Munevar, C, Munoz Camacho, P, Nadel-Turonski, L A, Net, G, Niculescu, M, Osipenko, A I, Ostrovidov, M, Paolone, K, Park, E, Pasyuk, J J, Phillips, S, Pisano, O, Pogorelko, J W, Price, S, Procureur, Y, Prok, A J R, Puckett, B A, Raue, M, Ripani, A, Rizzo, G, Rosner, P, Rossi, P, Roy, F, Sabatié, C, Salgado, D, Schott, R A, Schumacher, E, Seder, A, Simonyan, Iu, Skorodumina, G D, Smith, D, Sokhan, N, Sparveris, S, Stepanyan, I I, Strakovsky, S, Strauch, V, Sytnik, Ye, Tian, S, Tkachenko, M, Ungaro, H, Voskanyan, E, Voutier, N K, Walford, D P, Watts, X, Wei, L B, Weinstein, M H, Wood, N, Zachariou, L, Zana, J, Zhang, Z W, Zhao, I, Zonta, 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), Thomas Jefferson National Accelerator Facility (Jefferson Lab), 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, Rensselaer Polytechnic Institute (RPI), Old Dominion University [Norfolk] (ODU), Argonne National Laboratory [Lemont] (ANL), Universidad Tecnica Federico Santa Maria [Valparaiso] (UTFSM), University of Connecticut (UCONN), Ohio University, Carnegie Mellon University [Pittsburgh] (CMU), 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, Photon, Proton, HERA, General Physics and Astronomy, Socio-culturale, FOS: Physical sciences, Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], High Energy Physics - Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, High Energy Physics - Experiment (hep-ex), CLAS, virtual compton scattering, Twist, Nuclear Experiment (nucl-ex), VIRTUAL COMPTON-SCATTERING, NUCLEON, Nuclear Experiment, Quantum chromodynamics, Physics, 3. Good health, Phase space, virtual compton scattering, nucleon, High Energy Physics::Experiment, Nucleon
Abstract: Unpolarized and beam-polarized four-fold cross sections $\frac{d^4 \sigma}{dQ^2 dx_B dt d\phi}$ for the $ep\to e^\prime p^\prime \gamma$ reaction were measured using the CLAS detector and the 5.75-GeV polarized electron beam of the Jefferson Lab accelerator, for 110 ($Q^2,x_B,t$) bins over the widest phase space ever explored in the valence-quark region. Several models of Generalized Parton Distributions (GPDs) describe the data well at most of our kinematics. This increases our confidence that we understand the GPD $H$, expected to be the dominant contributor to these observables. Through a leading-twist extraction of Compton Form Factors, these results reveal a tomographic image of the nucleon., Comment: 7 pages, 5 figures
Published: 2015

27. Precision measurements ofg1of the proton and of the deuteron with 6 GeV electrons

Author: P. Lenisa, N. A. Baltzell, D. Meekins, E. De Sanctis, M. Aghasyan, C. Keith, D. I. Sober, Friedrich Klein, K. A. Griffioen, G. Rosner, M. Contalbrigo, L. Elouadrhiri, V. Crede, O. Pogorelko, Y. Ghandilyan, F. Sabatié, P. Roy, C. Smith, Diane Schott, Victor Mokeev, C. Hanretty, D. S. Carman, R. A. Montgomery, M. J. Amaryan, D. Adikaram, A. I. Ostrovidov, K. Park, K. Hicks, J. W. Price, S. Strauch, S. Fegan, H. S. Jo, H. Moutarde, S. Tkachenko, A. V. Vlassov, D. G. Ireland, G. D. Smith, S. Stepanyan, M. Holtrop, D. Protopopescu, K. Joo, W. Tang, A. Movsisyan, E. Voutier, T. Mineeva, K. L. Giovanetti, Larry Weinstein, B. Zhao, S. Pozdniakov, M. Garçon, Nicholas Kvaltine, R. A. Schumacher, I. Zonta, P. Bosted, N. Harrison, Volker D. Burkert, A. S. Biselli, S. Koirala, M. Osipenko, A. Kim, B. Guegan, S. S. Jawalkar, J. J. Phillips, R. De Vita, M. Ungaro, J. Brock, S. Anefalos Pereira, H. Voskanyan, Y. Prok, W. Gohn, S. Bültmann, K. Hafidi, Y. G. Sharabian, C. Carlin, R. G. Fersch, I. I. Strakovsky, S. S. Stepanyan, I. J. D. MacGregor, Andrew Puckett, T. A. Forest, V. Sytnik, P. L. Cole, B. Garillon, K. Livingston, Jie Zhang, Martin K. Mayer, R. W. Gothe, A. Deur, N. Kalantarians, Gerard Gilfoyle, J. Pierce, Avraham Klein, B. Vernarsky, Y. Ilieva, N. K. Walford, S. Chandavar, W. Kim, N. Guler, G. Niculescu, D. Sokhan, L. Colaneri, M. S. Saini, W. J. Briscoe, J. Bono, P. Nadel-Turonski, D. Doughty, Chaden Djalali, B. S. Ishkhanov, L. El Fassi, D. Keller, N. Markov, M. Taiuti, P. Rossi, S. Pisano, A. Simonyan, Sergey Kuleshov, R. Paremuzyan, G. E. Dodge, H. Y. Lu, M. Mirazita, P. Peng, H. Avakian, C. Munoz Camacho, A. El Alaoui, W. K. Brooks, F. X. Girod, Z. W. Zhao, D. P. Watts, I. Niculescu, B. McKinnon, N. Gevorgyan, D. Ho, J. P. Ball, M. Khandaker, Nicholas Zachariou, M. Ripani, L. L. Pappalardo, V. P. Kubarovsky, Andrea Celentano, S. E. Kuhn, A. Rizzo, D. Rimal, S. Procureur, J. A. Fleming, E. Munevar, Annalisa D'Angelo, S. Niccolai, D. G. Crabb, B. A. Raue, N. Dashyan, M. Battaglieri, H. Baghdasaryan, Lorenzo Zana, G. V. Fedotov, K. P. Adhikari, X. Jiang, E. Seder, M. Hattawy, C. Salgado, J. T. Goetz, O. Cortes, E. L. Isupov, R. Dupre, 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), CLAS, 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, Particle physics, FOS: Physical sciences, SPIN STRUCTURE, INELASTIC EP, SCATTERING, NUCLEON, CLAS, Electron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, Settore FIS/04 - Fisica Nucleare e Subnucleare, NO, Nuclear physics, Invariant mass, Nuclear Experiment (nucl-ex), Nuclear Experiment, Quantum chromodynamics, Physics, Scattering, Polarization (waves), Deuterium, Quark–gluon plasma, High Energy Physics::Experiment, Nucleon
Abstract: The inclusive polarized structure functions of the proton and deuteron, g(1)(p) and g(1)(d) , were measured with high statistical precision using polarized 6 GeV electrons incident on a polarized ammonia target in Hall B at Jefferson Laboratory. Electrons scattered at laboratory angles between 18 and 45 degrees were detected using the CEBAF Large Acceptance Spectrometer (CLAS). For the usual deep inelastic region kinematics, Q(2) > 1 GeV2 and the final-state invariant mass W > 2 GeV, the ratio of polarized to unpolarized structure functions g(1)/F-1 is found to be nearly independent of Q(2) at fixed x. Significant resonant structure is apparent at values of W up to 2.3 GeV. In the framework of perturbative quantum chromodynamics, the high-W results can be used to better constrain the polarization of quarks and gluons in the nucleon, as well as high-twist contributions.
Published: 2014

28. Exclusiveπ0electroproduction atW>2 GeV with CLAS

Author: Latifa Elouadrhiri, P. Lenisa, J. P. Ball, Y. Prok, H. Moutarde, D. S. Carman, G. V. Fedotov, E. De Sanctis, K. L. Giovanetti, Larry Weinstein, C. Djalali, A. Movsisyan, Friedrich Klein, D. I. Sober, H. Hakobyan, K. P. Adhikari, W. Phelps, Brian Raue, D. Doughty, W. Tang, P. Roy, E. Voutier, M. Osipenko, V. Crede, P. Eugenio, A. V. Vlassov, E. Golovatch, B. Guegan, S. Fegan, R. A. Montgomery, K. Livingston, Y. Ghandilyan, F. Sabatié, J. Bono, B. S. Ishkhanov, R. De Vita, I. Bedlinskiy, H. Y. Lu, A. D'Angelo, C. I. Moody, G. D. Smith, M. Holtrop, S. E. Kuhn, N. Dashyan, B. Garillon, M. Hattawy, J. A. Fleming, Z. W. Zhao, Barry Ritchie, Luciano Pappalardo, I. Zonta, S. Anefalos Pereira, S. Chandavar, H. Avakian, L. El Fassi, P. Stoler, W. J. Briscoe, W. Kim, X. Wei, S. Procureur, Lorenzo Zana, I. Niculescu, I. Senderovich, K. Hicks, M. Khandaker, N. K. Walford, H. Voskanyan, A. Kim, P. Rossi, L. Guo, W. I. Levine, R. A. Schumacher, S. Strauch, S. Park, Y. G. Sharabian, E. Seder, D. P. Watts, S. Niccolai, H. S. Jo, D. Protopopescu, H. Egiyan, A. Deur, P. L. Cole, N. Harrison, Andrew Puckett, T. A. Forest, M. Garçon, W. K. Brooks, R. Dupre, Alessandro Rizzo, Martin K. Mayer, Avraham Klein, P. Nadel-Turonski, M. Battaglieri, Sergey Kuleshov, A. El Alaoui, J. J. Phillips, Nicholas Zachariou, G. Gavalian, Dustin Keller, M. Ripani, K. Hafidi, A. Simonyan, C. Salgado, I. J. D. MacGregor, M. Yurov, S. S. Stepanyan, V. P. Kubarovsky, O. Pogorelko, V. Sytnik, M. Contalbrigo, Gerard Gilfoyle, L. Colaneri, N. Markov, D. Sokhan, A. Celentano, R. W. Gothe, S. Pisano, O. Cortes, E. L. Isupov, Ye Tian, Diane Schott, S. Boiarinov, A. I. Ostrovidov, K. Park, D. G. Ireland, Volker D. Burkert, A. S. Biselli, C. Munoz Camacho, B. McKinnon, M. Mirazita, E. Phelps, N. Gevorgyan, V. Batourine, F. X. Girod, J. W. Price, S. Koirala, D. G. Jenkins, Eugene Pasyuk, N. A. Baltzell, K. A. Griffioen, Victor Mokeev, M. Ungaro, K. Joo, and J. Zhang
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Meson, Structure function, Magnitude (mathematics), Parton, Helicity, Nuclear physics, Transverse plane, Pi, High Energy Physics::Experiment, Vector meson, Nuclear Experiment
Abstract: Exclusive neutral-pion electroproduction (ep-->e'p'pi0) was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections d4sigma/dtdQ2dxBdphipi and structure functions sigmaT+epsilonsigmaL,sigmaTT and σLT as functions of t were obtained over a wide range of Q2 and xB. The data are compared with Regge and handbag theoretical calculations. Analyses in both frameworks find that a large dominance of transverse processes is necessary to explain the experimental results. For the Regge analysis it is found that the inclusion of vector meson rescattering processes is necessary to bring the magnitude of the calculated and measured structure functions into rough agreement. In the handbag framework, there are two independent calculations, both of which appear to roughly explain the magnitude of the structure functions in terms of transversity generalized parton distributions.
Published: 2014

29. Induced polarization of {\Lambda}(1116) in kaon electroproduction

Author: B. S. Ishkhanov, A. Simonyan, W. Phelps, H. Hakobyan, H. S. Jo, C. A. Meyer, G. V. Fedotov, K. P. Adhikari, S. Strauch, P. Eugenio, S. E. Kuhn, M. Hattawy, J. A. Fleming, C. Salgado, F. X. Girod, V. P. Kubarovsky, Eugene Pasyuk, J. Bono, I. Bedlinskiy, P. Nadel-Turonski, N. Dashyan, S. Chandavar, O. Pogorelko, S. M. Hughes, F. Sabatié, M. J. Amaryan, S. Procureur, William Brooks, I. Zonta, X. Wei, H. Avakian, V. Baturin, Sergey Kuleshov, J. W. Price, N. K. Walford, B. Garillon, L. Zana, H. Voskanyan, H. Moutarde, R. Dupre, I. I. Strakovsky, M. Battaglieri, D. Ho, D. P. Watts, W. J. Briscoe, A. Deur, Yordanka Ilieva, S. Koirala, S. Niccolai, K. L. Giovanetti, S. S. Stepanyan, V. Sytnik, C. Djalali, Larry Weinstein, K. A. Griffioen, Alessandro Rizzo, Y. Ghandilyan, C. I. Moody, G. Charles, E. Golovatch, Dustin Keller, W. I. Levine, D. Adikaram, M. Guidal, G. Niculescu, D. G. Jenkins, R. A. Schumacher, G. D. Smith, M. Holtrop, M. Y. Gabrielyan, K. Hafidi, Luciano Pappalardo, M. Khandaker, J. P. Ball, T. A. Forest, D. S. Carman, M. Ripani, S. Stepanyan, E. Voutier, A. Movsisyan, E. Munevar, S. Fegan, V. Crede, A. V. Vlassov, R. De Vita, S. Anefalos Pereira, W. Tang, E. De Sanctis, M. Osipenko, D. I. Sober, W. Kim, Victor Mokeev, M. Ungaro, K. Joo, L. Guo, M. D. Mestayer, O. Cortes, Martin K. Mayer, S. Boiarinov, J. T. Goetz, K. Hicks, P. Lenisa, D. Doughty, Friedrich Klein, Brian Raue, A. D'Angelo, K. Livingston, L. El Fassi, R. Paremuzyan, Gerard Gilfoyle, J. J. Phillips, Jie Zhang, T. Cao, I. J. D. MacGregor, D. Sokhan, M. Contalbrigo, B. McKinnon, A. Celentano, R. W. Gothe, P. L. Cole, M. Mirazita, N. Gevorgyan, D. Protopopescu, S. Pozdniakov, P. Peng, C. Munoz Camacho, Diane Schott, N. A. Baltzell, K. Park, D. G. Ireland, H. Jiang, Volker D. Burkert, A. S. Biselli, Nicholas Zachariou, L. Colaneri, D. Rimal, S. Pisano, 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), CLAS, 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: Quark, Nuclear and High Energy Physics, Particle physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Induced polarization, DECAYS, Settore FIS/04 - Fisica Nucleare e Subnucleare, NO, Nuclear physics, CLAS, 0103 physical sciences, GAMMA-P, SIGMA(0), 010306 general physics, NUCLEON, Nuclear Experiment, PHOTON ENERGIES, PHOTOPRODUCTION, K+LAMBDA, SYSTEM, Physics, Spectrometer, 010308 nuclear & particles physics, Momentum transfer, Hyperon, Interaction model, Cathode ray, High Energy Physics::Experiment, Nucleon
Abstract: We have measured the induced polarization of the ${\Lambda}(1116)$ in the reaction $ep\rightarrow e'K^+{\Lambda}$, detecting the scattered $e'$ and $K^+$ in the final state along with the proton from the decay $\Lambda\rightarrow p\pi^-$.The present study used the CEBAF Large Acceptance Spectrometer (CLAS), which allowed for a large kinematic acceptance in invariant energy $W$ ($1.6\leq W \leq 2.7$ GeV) and covered the full range of the kaon production angle at an average momentum transfer $Q^2=1.90$ GeV$^2$.In this experiment a 5.50 GeV electron beam was incident upon an unpolarized liquid-hydrogen target. We have mapped out the $W$ and kaon production angle dependencies of the induced polarization and found striking differences from photoproduction data over most of the kinematic range studied. However, we also found that the induced polarization is essentially $Q^2$ independent in our kinematic domain, suggesting that somewhere below the $Q^2$ covered here there must be a strong $Q^2$ dependence. Along with previously published photo- and electroproduction cross sections and polarization observables, these data are needed for the development of models, such as effective field theories, and as input to coupled-channel analyses that can provide evidence of previously unobserved $s$-channel resonances., Comment: 13 figures
Published: 2014

30. The CLAS Electromagnetic Calorimeter at Large Angles

Author: Paolo Rossi, H. Avakian, Marco Ripani, V. Sapunenko, Victor Mokeev, R. De Vita, P. Corvisiero, M. Battaglieri, E. Polli, M. Mirazita, M. Taiuti, F. Ronchetti, V. Muccifora, V. Gyuriyan, M. Anghinolfi, N. Bianchi, M. Osipenko, E. Golovach, and Giovanni Ricco
Subjects: Physics, Nuclear and High Energy Physics, Spectrometer, Physics::Instrumentation and Detectors, Monte Carlo method, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Scintillator, Calorimeter, Nuclear physics, Electromagnetic calorimeter, Calibration, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Instrumentation, Nuclear Experiment, Energy (signal processing)
Abstract: The study of the response of the two modules of the large-angle electromagnetic shower calorimeter (LAC) of the CLAS detector to charged and neutral particles is reported. The results agree very well with the Monte Carlo simulation. The procedures adopted for the energy and timing calibration are also discussed, proving that the module geometry allows for simple self-calibrating energy and timing algorithms.
Published: 2014

31. Exclusive π0 electroproduction at W>2 GeV with CLAS

Author: I. BedlinskiyInstitute of Theoretical and Experimental Physics, V. Kubarovsky(Thomas Jefferson National Accelerator Facility), S. Niccolai(Institut de Physique Nucléaire ORSAY), P. Stoler(Rensselaer Polytechnic Institute), K. P. Adhikari(Old Dominion University), M. D. Anderson(University of Glasgow), S. Anefalos Pereira(INFN), H. Avakian(Thomas Jefferson National Accelerator Facility), J. Ball(CEA), N. A. Baltzell(Argonne National Laboratory), M. Battaglieri(INFN), V. Batourine(Thomas Jefferson National Accelerator Facility), A. S. Biselli(Thomas Jefferson National Accelerator Facility), S. Boiarinov(Thomas Jefferson National Accelerator Facility), J. Bono(Florida International University), W. J. Briscoe(The George Washington University), W. K. Brooks(Universidad Técnica Federico Santa María), V. D. Burkert(Thomas Jefferson National Accelerator Facility), D. S. Carman(Thomas Jefferson National Accelerator Facility), A. Celentano(INFN), S. Chandavar(Ohio University), L. Colaneri(INFN), P. L. Cole(Idaho State University), M. Contalbrigo(INFN), O. Cortes(Idaho State University), V. Crede(Florida State University), A. D'Angelo(INFN), N. Dashyan(Yerevan Physics Institute), R. De Vita(INFN), E. De Sanctis(INFN), A. Deur(Thomas Jefferson National Accelerator Facility), C. Djalali(University of South Carolina), D. Doughty(Christopher Newport University), R. Dupre(Institut de Physique Nucléaire ORSAY), H. Egiyan(Thomas Jefferson National Accelerator Facility), A. El Alaoui(Argonne National Laboratory), L. El Fassi(Old Dominion University), L. Elouadrhiri(Thomas Jefferson National Accelerator Facility), P. Eugenio(Florida State University), G. Fedotov(University of South Carolina), S. Fegan(INFN), J. A. Fleming(Edinburgh University), T. A. Forest(Idaho State University), B. Garillon(Institut de Physique Nucléaire ORSAY), M. Gar\c con(CEA), G. Gavalian(Old Dominion University), N. Gevorgyan(Yerevan Physics Institute), Y. Ghandilyan(Yerevan Physics Institute), G. P. Gilfoyle(University of Richmond), K. L. Giovanetti(James Madison University), F. X. Girod(Thomas Jefferson National Accelerator Facility), E. Golovatch(Skobeltsyn Institute of Nuclear Physics), R. W. Gothe(University of South Carolina), K. A. Griffioen(Institut de Physique Nucléaire ORSAY), B. Guegan(Institut de Physique Nucléaire ORSAY), L. Guo(Florida International University), K. Hafidi(Argonne National Laboratory), H. Hakobyan(Universidad Técnica Federico Santa María), N. Harrison(University of Connecticut), M. Hattawy(Institut de Physique Nucléaire ORSAY), K. Hicks(Ohio University), M. Holtrop(University of New Hampshire), D. G. Ireland(University of Glasgow), B. S. Ishkhanov(Skobeltsyn Institute of Nuclear Physics), E. L. Isupov(Skobeltsyn Institute of Nuclear Physics), D. Jenkins(Institut de Physique Nucléaire ORSAY), H. S. Jo(Institut de Physique Nucléaire ORSAY), K. Joo(University of Connecticut), D. Keller(University of Virginia), M. Khandaker(Idaho State University), A. Kim(University of Connecticut), W. Kim(Kyungpook National University), A. Klein(Old Dominion University), F. J. Klein(Catholic University of America), S. Koirala(Old Dominion University), S. E. Kuhn(Old Dominion University), S. V. Kuleshov(Universidad Técnica Federico Santa María), P. Lenisa(INFN), W. I. Levine(Carnegie Mellon University), K. Livingston(University of Glasgow), H. Y. Lu(University of South Carolina), I . J . D. MacGregor(University of Glasgow), N. Markov(University of Connecticut), M. Mayer(Old Dominion University), B. McKinnon(University of Glasgow), M. Mirazita(INFN), V. Mokeev(Thomas Jefferson National Accelerator Facility), R. A. Montgomery(INFN), C. I. Moody(Argonne National Laboratory), H. Moutarde(CEA), A Movsisyan(INFN), C. Munoz Camacho(Institut de Physique Nucléaire ORSAY), P. Nadel-Turonski(Thomas Jefferson National Accelerator Facility), I. Niculescu(James Madison University), M. Osipenko(INFN), A. I. Ostrovidov(Florida State University), L. L. Pappalardo(INFN), K. Park(Thomas Jefferson National Accelerator Facility), S. Park(Florida State University), E. Pasyuk(Thomas Jefferson National Accelerator Facility), E. Phelps(University of South Carolina), W. Phelps(Florida International University), J. J. Phillips(University of Glasgow), S. Pisano(INFN), O. Pogorelko(Institute of Theoretical and Experimental Physics), J. W. Price(California State University), Y. Prok(Old Dominion University), D. Protopopescu(University of Glasgow), S. Procureur(CEA), A. J. R. Puckett(University of Connecticut), B. A. Raue(Florida International University), M. Ripani(INFN), B. G. Ritchie(Arizona State University), A. Rizzo(INFN), P. Rossi(INFN), P. Roy(Florida State University), F. Sabatié(CEA), C. Salgado(Norfolk State University), D. Schott(The George Washington University), R. A. Schumacher(Carnegie Mellon University), E. Seder(University of Connecticut), I. Senderovich(Arizona State University), Y. G. Sharabian(Thomas Jefferson National Accelerator Facility), A. Simonyan(Yerevan Physics Institute), G. D. Smith(Edinburgh University), D. I. Sober(Catholic University of America), D. Sokhan(University of Glasgow), S. S. Stepanyan(Kyungpook National University), S. Strauch(University of South Carolina), V. Sytnik(Universidad Técnica Federico Santa María), W. Tang(Ohio University), Ye Tian(University of South Carolina), M. Ungaro(Thomas Jefferson National Accelerator Facility), A. V. Vlassov(Institute of Theoretical and Experimental Physics), H. Voskanyan(Yerevan Physics Institute), E. Voutier(LPSC), N. K. Walford(Catholic University of America), D. Watts(University of Glasgow), X. Wei(Thomas Jefferson National Accelerator Facility), L. B. Weinstein(Old Dominion University), M. Yurov(University of Virginia), N. Zachariou(University of South Carolina), L. Zana(Edinburgh University), J. Zhang(Thomas Jefferson National Accelerator Facility), Z. W. Zhao(University of Virginia), I. Zonta(INFN), and for the CLAS Collaboration()
Subjects: hep-ex, High Energy Physics::Experiment, Nuclear Experiment, nucl-ex, NO
Abstract: Exclusive neutral-pion electroproduction ($ep\to e^\prime p^\prime \pi^0$) was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections $d^4\sigma/dtdQ^2dx_Bd\phi_\pi$ and structure functions $\sigma_T+\epsilon\sigma_L, \sigma_{TT}$ and $\sigma_{LT}$ as functions of $t$ were obtained over a wide range of $Q^2$ and $x_B$. The data are compared with Regge and handbag theoretical calculations. Analyses in both frameworks find that a large dominance of transverse processes is necessary to explain the experimental results. For the Regge analysis it is found that the inclusion of vector meson rescattering processes is necessary to bring the magnitude of the calculated and measured structure functions into rough agreement. In the handbag framework, there are two independent calculations, both of which appear to roughly explain the magnitude of the structure functions in terms of transversity generalized parton distributions.
Published: 2014

32. $\phi$-meson photoproduction on Hydrogen in the neutral decay mode

Author: D. Doughty, Michael Wood, D. Heddle, K. Livingston, K. Hafidi, Jie Zhang, W. Kim, Victor Mokeev, N. Guler, Y. Ilieva, R. De Vita, W. J. Briscoe, P. Rossi, H. Y. Lu, M. J. Amaryan, S. Lewis, D. S. Carman, E. Munevar, N. A. Baltzell, H. Moutarde, P. Eugenio, E. Seder, N. Dashyan, M. Ungaro, K. L. Giovanetti, C. E. Hyde, K. A. Griffioen, Larry Weinstein, J. Bono, P. Nadel-Turonski, D. Protopopescu, W. Gohn, S. Pozdniakov, I. Niculescu, B. S. Ishkhanov, D. Keller, A. Kim, F. X. Girod, Z. W. Zhao, D. Ho, L. Weinstein, V. P. Kubarovsky, K. Joo, Barry Ritchie, P. Stoler, I. I. Strakovsky, Annalisa D'Angelo, H. Hakobyan, C. Hanretty, Andrea Celentano, R. Paremuzyan, M. Khandaker, A. Deur, K. Hicks, Nicholas Zachariou, H. Avakian, M. Ripani, W. Tang, S. E. Kuhn, W. K. Brooks, D. P. Watts, J. A. Fleming, J. J. Phillips, D. Rimal, M. Osipenko, C. E. Taylor, H. Baghdasaryan, S. Tkachenko, L. Guo, N. K. Walford, G. V. Fedotov, H. Voskanyan, G. Rosner, R. Nasseripour, I. J. D. MacGregor, E. Pasyuk, K. P. Adhikari, E. Golovatch, E. Voutier, Andrew Puckett, Martin K. Mayer, S. Strauch, D. Martinez, R. P. Bennett, E. De Sanctis, N. Harrison, R. G. Fersch, S. Fegan, M. Aghasyan, D. Adikaram, M. Guidal, Friedrich Klein, M. S. Saini, I. Bedlinskiy, R. A. Schumacher, D. I. Sober, G. D. Smith, M. Holtrop, D. Sokhan, J. P. Ball, S. Chandavar, Luciano Pappalardo, A. Rizzo, S. Park, R. W. Gothe, R. Dupre, M. Battaglieri, S. Niccolai, T. Mineeva, O. Pogorelko, P. Collins, M. F. Vineyard, Diane Schott, L. El Fassi, S. Bültmann, Sergey Kuleshov, A. I. Ostrovidov, K. Park, H. Seraydaryan, S. Anefalos Pereira, Y. G. Sharabian, A. Kubarovsky, S. Stepanyan, D. G. Ireland, V. Crede, Volker D. Burkert, M. Contalbrigo, A. S. Biselli, R. A. Montgomery, J. T. Goetz, H. S. Jo, S. Pisano, C. Munoz Camacho, Lorenzo Zana, B. McKinnon, M. Mirazita, C. Salgado, E. Phelps, N. Gevorgyan, V. Batourine, O. Cortes, E. L. Isupov, Ye Tian, S. Boiarinov, F. Sabatié, J. W. Price, G. Gavalian, S. Koirala, Chaden Djalali, Michael Dugger, Old Dominion University [Norfolk] (ODU), 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), 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, CLAS, and 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)
Subjects: Nuclear and High Energy Physics, Particle physics, Meson, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Settore FIS/04 - Fisica Nucleare e Subnucleare, High Energy Physics - Experiment, Nuclear physics, Pion, LARGE MOMENTUM-TRANSFER, DRIFT CHAMBER SYSTEM, CLAS, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], PERTURBATIVE QCD, SPECTROMETER, Invariant mass, NEAR-THRESHOLD, Nuclear Experiment, DETECTOR, Physics, Spectrometer, Perturbative QCD, Phi meson, Baryon, BARYON RESONANCES, High Energy Physics::Experiment, Energy (signal processing)
Abstract: See paper for full list of authors; We report the first measurement of the photoproduction cross section of the $\phi$ meson in its neutral decay mode in the reaction $\gamma p \to p\phi(K_SK_L)$. The experiment was performed with a tagged photon beam of energy $1.6 \le E_\gamma \le 3.6$ GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The $p \phi$ final state is identified via reconstruction of $K_S$ in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction $\gamma p \to p K_S X$ to be $K_L$. The presented results significantly enlarge the existing data on $\phi$-photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of $\phi$ photoproduction.
Published: 2014

33. Beam-spin Asymmetries from Semi-inclusive Pion Electroproduction

Author: P. Lenisa, R. Dupre, J. Bono, P. Nadel-Turonski, M. Battaglieri, I. Zonta, G. V. Fedotov, V. Crede, Friedrich Klein, C. Hanretty, S. Niccolai, H. Avakian, S. Strauch, Brian Raue, F. X. Girod, R. Paremuzyan, K. P. Adhikari, B. S. Ishkhanov, P. Eugenio, N. K. Walford, M. Ungaro, H. Voskanyan, George Davey Smith, S. Chandavar, C. E. Hyde, H. Y. Lu, W. Kim, E. Pasyuk, W. J. Briscoe, G. Charles, P. Khetarpal, I. I. Strakovsky, S. Pisano, Gerard Gilfoyle, S. Procureur, C. Djalali, I. Niculescu, K. Joo, F. Sabatié, H. Seraydaryan, D. Sokhan, E. Seder, J. J. Phillips, Y. G. Sharabian, D. Ho, B. Vernarsky, D. S. Carman, Y. Prok, Dustin Keller, N. A. Baltzell, A. D'Angelo, L. El Fassi, O. Cortes, B. McKinnon, A. Movsisyan, M. Garçon, I. J. D. MacGregor, W. K. Brooks, E. Voutier, P. Roy, Barry Ritchie, M. Contalbrigo, L. Zana, G. Rosner, J. W. Price, Victor Mokeev, J. Ball, Michael Wood, W. Tang, D. P. Watts, K. Hafidi, T. Mineeva, Y. Ghandilyan, H. S. Jo, E. De Sanctis, B. Guegan, M. Mirazita, M. Holtrop, M. Osipenko, R. A. Schumacher, Diane Schott, A. I. Ostrovidov, M. Aghasyan, Luciano Pappalardo, K. Park, A. Simonyan, S. Koirala, D. G. Ireland, D. I. Sober, S. E. Kuhn, T. A. Forest, N. Markov, Volker D. Burkert, A. S. Biselli, S. Stepanyan, J. A. Fleming, Sergey Kuleshov, A. Celentano, R. De Vita, R. W. Gothe, V. P. Kubarovsky, Mohammad Hattawy, S. Anefalos Pereira, N. Dashyan, P. L. Cole, P. Peng, K. A. Griffioen, Andrew Puckett, Martin K. Mayer, W. Gohn, P. Stoler, K. Hicks, S. Tkachenko, L. Guo, Alessandro Rizzo, N. Harrison, K. Livingston, Jie Zhang, P. Rossi, S. Pozdniakov, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, M. Ripani, M. Khandaker, C. Salgado, M. J. Amaryan, K. L. Giovanetti, Larry Weinstein, D. Doughty, University of Connecticut (UCONN), 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), 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, CLAS, and 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)
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Scattering, FOS: Physical sciences, Large range, Electron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Deep inelastic scattering, High Energy Physics - Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare, High Energy Physics - Experiment (hep-ex), Pion, Reaction model, Statistical precision, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract: We have measured the moment $A_{LU}^{\sin\phi}$ corresponding to the polarized electron beam-spin asymmetry in SIDIS. $A_{LU}^{\sin\phi}$ is a twist-3 quantity providing information about quark-gluon correlations. Data were taken with the CLAS Spectrometer at Jefferson Lab using a 5.498 GeV longitudinally polarized electron beam and an unpolarized liquid hydrogen target. All three pion channels ($\pi^+$, $\pi^0$ and $\pi^-$) were measured simultaneously over a large range of kinematics within the virtuality range $Q^2 \approx$ 1.0-4.5 GeV$^2$. The observable was measured with better than 1% statistical precision over a large range of $z$, $P_T$, $x_B$, and $Q^{2}$, which permits comparison with several reaction models. The discussed measurements provide an upgrade in statistics over previous measurements, and serve as the first evidence for the negative sign of the $\pi^{-}$ $\sin\phi$ moment., Comment: 16 pages, 18 figures
Published: 2014

34. Measurement of the Spin Asymmetry in the Photoproduction of Pairs of High-pTHadrons at HERMES

Author: A. Airapetian, N. Akopov, M. Amarian, E. C. Aschenauer, H. Avakian, R. Avakian, A. Avetissian, B. Bains, C. Baumgarten, M. Beckmann, S. Belostotski, J. E. Belz, Th. Benisch, S. Bernreuther, N. Bianchi, J. Blouw, H. Böttcher, A. Borissov, J. Brack, S. Brauksiepe, B. Braun, W. Brückner, A. Brüll, H. J. Bulten, G. P. Capitani, P. Carter, P. Chumney, E. Cisbani, G. R. Court, P. F. Dalpiaz, E. De Sanctis, D. De Schepper, E. Devitsin, P. K. A. de Witt Huberts, P. Di Nezza, M. Düren, A. Dvoredsky, G. Elbakian, J. Ely, A. Fantoni, M. Ferstl, K. Fiedler, B. W. Filippone, H. Fischer, B. Fox, J. Franz, S. Frullani, M.-A. Funk, Y. Gärber, F. Garibaldi, G. Gavrilov, P. Geiger, V. Gharibyan, A. Golendukhin, G. Graw, O. Grebeniouk, P. W. Green, L. G. Greeniaus, C. Grosshauser, M. Guidal, A. Gute, W. Haeberli, J.-O. Hansen, D. Hasch, O. Häusser, F. H. Heinsius, R. Henderson, M. Henoch, R. Hertenberger, Y. Holler, R. J. Holt, W. Hoprich, H. Ihssen, M. Iodice, A. Izotov, H. E. Jackson, A. Jgoun, R. Kaiser, E. Kinney, A. Kisselev, P. Kitching, H. Kobayashi, N. Koch, K. Königsmann, M. Kolstein, H. Kolster, V. Korotkov, W. Korsch, V. Kozlov, L. H. Kramer, M. Kurisuno, G. Kyle, W. Lachnit, W. Lorenzon, N. C. R. Makins, F. K. Martens, J. W. Martin, F. Masoli, A. Mateos, M. McAndrew, K. McIlhany, R. D. McKeown, F. Meissner, F. M. Menden, A. Metz, N. Meyners, O. Mikloukho, C. A. Miller, M. A. Miller, R. Milner, A. Most, V. Muccifora, Y. Naryshkin, A. M. Nathan, F. Neunreither, M. Niczyporuk, W.-D. Nowak, T. G. O'Neill, R. Openshaw, J. Ouyang, B. R. Owen, S. F. Pate, S. Potashov, D. H. Potterveld, G. Rakness, R. Redwine, A. R. Reolon, R. Ristinen, K. Rith, P. Rossi, S. Rudnitsky, M. Ruh, D. Ryckbosch, Y. Sakemi, C. Scarlett, A. Schäfer, F. Schmidt, H. Schmitt, G. Schnell, K. P. Schüler, A. Schwind, J. Seibert, T.-A. Shibata, K. Shibatani, T Shin, V. Shutov, C. Simani, A. Simon, K. Sinram, P. Slavich, M. Spengos, E. Steffens, J. Stenger, J. Stewart, U. Stoesslein, M. Sutter, H. Tallini, S. Taroian, A. Terkulov, B. Tipton, M. Tytgat, G. M. Uriuoli, R. van de Vyver, J. F. J. van den Brand, G. van der Steenhoven, J. J. van Hunen, M. C. Vetterli, V. Vikhrov, M. G. Vincter, J. Visser, E. Volk, W. Wander, J. Wendland, S. E. Williamson, T. Wise, K. Woller, S. Yoneyama, and H. Zohrabian
Subjects: HERMES experiment, Physics, Particle physics, media_common.quotation_subject, Hadron, General Physics and Astronomy, HERA, Polarization (waves), Deep inelastic scattering, Asymmetry, Gluon, Nuclear physics, High Energy Physics::Experiment, Nuclear Experiment, Storage ring, media_common
Abstract: We present a measurement of the longitudinal spin asymmetry A|| in photoproduction of pairs of hadrons with high transverse momentum pT. Data were accumulated by the HERMES experiment using a 27.5 GeV polarized positron beam and a polarized hydrogen target internal to the HERA storage ring. For h^+h^- pairs with _(pT)^(h1)>1.5GeV/c and _(pT)^(h2)>1.0GeV/c, the measured asymmetry is A_(||) = -0.28±0.12(stat)±0.02(syst). This negative value is in contrast to the positive asymmetries typically measured in deep inelastic scattering from protons, and is interpreted to arise from a positive gluon polarization.
Published: 2000

35. Observation of a Coherence Length Effect in Exclusiveρ0Electroproduction

Author: K. Ackerstaff, A. Airapetian, N. Akopov, I. Akushevich, M. Amarian, E. C. Aschenauer, H. Avakian, R. Avakian, A. Avetissian, B. Bains, S. Barrow, C. Baumgarten, M. Beckmann, St. Belostotski, J. E. Belz, Th. Benisch, S. Bernreuther, N. Bianchi, S. Blanchard, J. Blouw, H. Böttcher, A. Borissov, J. Brack, S. Brauksiepe, B. Braun, B. Bray, St. Brons, W. Brückner, A. Brüll, E. E. W. Bruins, H. J. Bulten, R. V. Cadman, G. P. Capitani, P. Carter, P. Chumney, E. Cisbani, G. R. Court, P. F. Dalpiaz, P. P. J. Delheij, E. De Sanctis, D. De Schepper, E. Devitsin, P. K. A. de Witt Huberts, P. Di Nezza, M. Düren, A. Dvoredsky, G. Elbakian, J. Ely, J. Emerson, A. Fantoni, A. Fechtchenko, M. Ferstl, D. Fick, K. Fiedler, B. W. Filippone, H. Fischer, H. T. Fortune, B. Fox, S. Frabetti, J. Franz, S. Frullani, M.-A. Funk, N. D. Gagunashvili, P. Galumian, H. Gao, Y. Gärber, F. Garibaldi, G. Gavrilov, P. Geiger, V. Gharibyan, V. Giordjian, A. Golendukhin, G. Graw, O. Grebeniouk, P. W. Green, L. G. Greeniaus, C. Grosshauser, M. G. Guidal, A. Gute, V. Gyurjyan, J. P. Haas, W. Haeberli, J.-O. Hansen, D. Hasch, O. Häusser, F. H. Heinsius, R. S. Henderson, Th. Henkes, M. Henoch, R. Hertenberger, Y. Holler, R. J. Holt, W. Hoprich, H. Ihssen, M. Iodice, A. Izotov, H. E. Jackson, A. Jgoun, C. Jones, R. Kaiser, E. Kinney, M. Kirsch, A. Kisselev, P. Kitching, H. Kobayashi, N. Koch, K. Königsmann, M. Kolstein, H. Kolster, V. Korotkov, W. Korsch, V. Kozlov, L. H. Kramer, B. Krause, V. G. Krivokhijine, M. Kückes, F. Kümmell, G. Kyle, W. Lachnit, W. Lorenzon, A. Lung, N. C. R. Makins, F. K. Martens, J. W. Martin, F. Masoli, A. Mateos, M. McAndrew, K. McIlhany, R. D. McKeown, F. Meissner, F. Menden, D. Mercer, A. Metz, N. Meyners, O. Mikloukho, C. A. Miller, M. A. Miller, R. G. Milner, V. Mitsyn, A. Most, R. Mozzetti, V. Muccifora, A. Nagaitsev, Y. Naryshkin, A. M. Nathan, F. Neunreither, M. Niczyporuk, W.-D. Nowak, M. Nupieri, P. Oelwein, H. Ogami, T. G. O'Neill, R. Openshaw, J. Ouyang, B. R. Owen, V. Papavassiliou, S. F. Pate, M. Pitt, H. R. Poolman, S. Potashov, D. H. Potterveld, B. Povh, G. Rakness, A. Reali, R. Redwine, A. R. Reolon, R. Ristinen, K. Rith, H. Roloff, G. Röper, P. Rossi, S. Rudnitsky, M. Ruh, D. Ryckbosch, Y. Sakemi, I. Savin, C. Scarlett, F. Schmidt, H. Schmitt, G. Schnell, K. P. Schüler, A. Schwind, J. Seibert, T.-A. Shibata, T. Shin, V. Shutov, C. Simani, A. Simon, K. Sinram, P. Slavich, J. Sowinski, M. Spengos, E. Steffens, J. Stenger, J. Stewart, F. Stock, U. Stoesslein, M. Sutter, H. Tallini, S. Taroian, A. Terkulov, D. M. Thiessen, E. Thomas, B. Tipton, A. Trudel, M. Tytgat, G. M. Urciuoli, J. J. van Hunen, R. van de Vyver, J. F. J. van den Brand, G. van der Steenhoven, M. C. Vetterli, V. Vikhrov, M. Vincter, J. Visser, E. Volk, W. Wander, T. P. Welch, S. E. Williamson, T. Wise, T. Wölfel, K. Woller, S. Yoneyama, K. Zapfe-Düren, H. Zohrabian, and R. Zurmühle
Subjects: Physics, HERMES experiment, Particle physics, Meson, 010308 nuclear & particles physics, High Energy Physics::Lattice, High Energy Physics::Phenomenology, Nuclear Theory, General Physics and Astronomy, Virtual particle, 01 natural sciences, Coherence length, Positron energy, Nuclear physics, Deuterium, Nuclear transparency, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Nucleon
Abstract: Exclusive incoherent electroproduction of the ρ0(770) meson from 1H, 2H, 3He, and 14N targets has been studied by the HERMES experiment at squared four-momentum transfer Q^2>0.4 GeV^2 and positron energy loss ν from 9 to 20 GeV. The ratio of the 14N to 1H cross sections per nucleon, known as the nuclear transparency, was found to decrease with increasing coherence length of quark-antiquark fluctuations of the virtual photon. The data provide clear evidence of the interaction of the quark-antiquark fluctuations with the nuclear medium.
Published: 1999

36. Beam-induced nuclear depolarization in a gaseous polarized-hydrogen target

Author: Yasuhiro Sakemi, Valeri Valentinovitch Mitsyn, R. P. Redwine, G. van der Steenhoven, J. van Hunen, L. G. Greeniaus, A. Gute, L. H. Kramer, E. Volk, P. Chumney, S. Frullani, H. Schmitt, F. Stock, Ross Milner, T. A. Shibata, E. De Sanctis, R.O. Avakian, A. Metz, N. Koch, J. Franz, H. Kolster, M.-A. Funk, J.-O. Hansen, A.O. Mateos, A. Borissov, B. D. Fox, E. Devitsin, E. Cisbani, S. Potashov, H. Zohrabian, A. R. Reolon, A. Avetissian, K. McIlhany, I.A. Savin, K. Sinram, R. J. Holt, A. Izotov, T. Wise, F. Masoli, F. Neunreither, J. Blouw, S. Bernreuther, Alan M. Nathan, G.R. Court, F. Schmidt, R. V. Cadman, V. A. Korotkov, N.D. Gagunashvili, Y. Gärber, M. Beckmann, M. McAndrew, G. S. Kyle, H. J. Bulten, Michael Pitt, J. F. J. van den Brand, Th. Henkes, J. Stewart, V. Gharibyan, W. Haeberli, S. Frabetti, A. Brull, Brons, M. Ferstl, M. Sutter, M. Amarian, K. Ackerstaff, Klaus Rith, Robert Henderson, E. R. Kinney, Wolfgang Korsch, A. Reali, E. E. W. Bruins, H. Avakian, A. Airapetian, W. Wander, A. Dvoredsky, A. Nagaitsev, E. C. Aschenauer, H. E. Jackson, V. G. Krivokhijine, K. Königsmann, O. Häusser, G. P. Capitani, Y. Naryshkin, H. Ihssen, Michel Vetterli, M. Kolstein, Haiyan Gao, O. Grebeniouk, Ralf Hertenberger, M. Ruh, A. Schwind, A. Simon, F. K. Martens, M. Nupieri, G. Elbakian, W. Brückner, C. Baumgarten, M. Spengos, P. Di Nezza, S. Brauksiepe, N. Akopov, Michael Tytgat, V. Giordjian, A. Golendukhin, S. I. Manaenkov, M. A. Miller, G. Rakness, M. Henoch, P. Geiger, P. Slavich, V. A. Kozlov, S. Taroian, F. Meissner, P. Rossi, W. Lachnit, D. De Schepper, C. Grosshauser, R. A. Ristinen, Y. Holler, Alessandra Fantoni, N. Meyners, B. R. Owen, H.O. Roloff, P. F. Dalpiaz, G. Graw, D. Hasch, D. H. Potterveld, K. Zapfe-Düren, H. Böttcher, S. F. Pate, Jeffrey Brack, B. W. Filippone, F. Garibaldi, J. Stenger, D. Fick, J. E. Belz, R. D. McKeown, P.K.A. de Witt Huberts, M. Niczyporuk, A. Jgoun, Mauro Iodice, V. Papavassiliou, Belostotski, S. Yoneyama, R. Van de Vyver, G. M. Urciuoli, W.-D. Nowak, H. Ogami, T. Shin, Manuella Vincter, A. Kisselev, H. Tallini, Wolfgang Lorenzon, W. Hoprich, U. Stoesslein, H. Fischer, J. W. Martin, S. Rudnitsky, Dirk Ryckbosch, J. Sowinski, B. Tipton, Hiroaki Kobayashi, K. Fiedler, K. Woller, Thomas O'Neill, P.W. Green, B. Braun, K. P. Schüler, Nicola Bianchi, O. Mikloukho, V. Shutov, B. Bains, C. Simani, Naomi C R Makins, R. Mozzetti, Ralf Kaiser, E. Steffens, G. Gavrilov, A. Fechtchenko, B. Bray, P. Kitching, Th. Benisch, M. Düren, P. Carter, C. A. Miller, Adel Terkulov, Valeria Muccifora, G. Schnell, S. E. Williamson, and (Astro)-Particles Physics
Subjects: HERMES experiment, Physics, Hydrogen, General Physics and Astronomy, chemistry.chemical_element, FOS: Physical sciences, DESY, Depolarization, HERA, Magnetic field, High Energy Physics - Experiment, NO, High Energy Physics - Experiment (hep-ex), Bunches, chemistry, Physics::Accelerator Physics, High Energy Physics::Experiment, Atomic physics, Beam (structure)
Abstract: Spin-polarised atomic hydrogen is used as a gaseous polarised proton target in high energy and nuclear physics experiments operating with internal beams in storage rings. When such beams are intense and bunched, this type of target can be depolarised by a resonant interaction with the transient magnetic field generated by the beam bunches. This effect has been studied with the HERA positron beam in the HERMES experiment at DESY. Resonances have been observed and a simple analytic model has been used to explain their shape and position. Operating conditions for the experiment have been found where there is no significant target depolarisation due to this effect., REVTEX, 6 pages, 5 figures
Published: 1999

37. Measurement of the proton spin structure function g(1)(p) with a pure hydrogen target

Author: A. Airapetian, N. Akopov, I. Akushevich, M. Amarian, E.C. Aschenauer, H. Avakian, R. Avakian, A. Avetissian, B. Bains, C. Baumgarten, M. Beckmann, St. Belostotski, E. Belz, Th. Benisch, S. Bernreuther, N. Bianchi, J. Blouw, H. Böttcher, A. Borissov, J. Brack, S. Brauksiepe, B. Braun, St. Brons, W. Brückner, A. Brüll, H.J. Bulten, G.P. Capitani, P. Carter, P. Chumney, E. Cisbani, G.R. Court, P.F. Dalpiaz, R. De Leo, E. De Sanctis, D. De Schepper, E. Devitsin, P.K.A. de Witt Huberts, P. Di Nezza, M. Düren, A. Dvoredsky, G. Elbakian, J. Ely, A. Fantoni, A. Fechtchenko, M. Ferstl, D. Fick, K. Fiedler, B.W. Filippone, H. Fischer, B. Fox, S. Frabetti, J. Franz, S. Frullani, M.-A. Funk, N.D. Gagunashvili, H. Gao, Y. Gärber, F. Garibaldi, G. Gavrilov, P. Geiger, V. Gharibyan, V. Giordjian, A. Golendukhin, G. Graw, O. Grebeniouk, P.W. Green, L.G. Greeniaus, C. Grosshauser, M. Guidal, A. Gute, W. Haeberli, J.-O. Hansen, D. Hasch, F.H. Heinsius, M. Henoch, R. Hertenberger, Y. Holler, R.J. Holt, W. Hoprich, H. Ihssen, M. Iodice, A. Izotov, H.E. Jackson, A. Jgoun, R. Kaiser, E. Kinney, A. Kisselev, P. Kitching, H. Kobayashi, N. Koch, K. Königsmann, M. Kolstein, H. Kolster, V. Korotkov, W. Korsch, V. Kozlov, L.H. Kramer, V.G. Krivokhijine, F. Kümmell, M. Kurisuno, G. Kyle, W. Lachnit, W. Lorenzon, N.C.R. Makins, S.I. Manaenkov, K. Martens, J.W. Martin, H. Marukyan, F. Masoli, A. Mateos, M. McAndrew, K. McIlhany, R.D. McKeown, F. Meißner, F. Menden, A. Metz, N. Meyners, O. Mikloukho, C.A. Miller, M.A. Miller, R. Milner, V. Mitsyn, A. Most, V. Muccifora, A. Nagaitsev, E. Nappi, Y. Naryshkin, A.M. Nathan, F. Neunreither, W.-D. Nowak, T.G. O'Neill, B.R. Owen, J. Ouyang, V. Papavassiliou, S.F. Pate, S. Potashov, D.H. Potterveld, G. Rakness, A. Reali, R. Redwine, A.R. Reolon, R. Ristinen, K. Rith, H. Roloff, P. Rossi, S. Rudnitsky, M. Ruh, D. Ryckbosch, Y. Sakemi, I. Savin, C. Scarlett, F. Schmidt, H. Schmitt, G. Schnell, K.P. Schüler, A. Schwind, J. Seibert, T.-A. Shibata, K. Shibatani, T. Shin, V. Shutov, C. Simani, A. Simon, K. Sinram, P. Slavich, M. Spengos, E. Steffens, J. Stenger, J. Stewart, U. Stößlein, M. Sutter, H. Tallini, S. Taroian, A. Terkulov, B. Tipton, M. Tytgat, G.M. Urciuoli, R. Van de Vyver, J.F.J. van den Brand, G. van der Steenhoven, J.J. van Hunen, M.C. Vetterli, M. Vincter, J. Visser, E. Volk, W. Wander, S.E. Williamson, T. Wise, K. Woller, S. Yoneyama, H. Zohrabian, and (Astro)-Particles Physics
Subjects: Nuclear and High Energy Physics, Particle physics, POLARIZATION, Hydrogen, Positron beam, FOS: Physical sciences, chemistry.chemical_element, 01 natural sciences, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), DEUTERON STRUCTURE FUNCTIONS, 0103 physical sciences, Proton spin crisis, Nuclear Experiment, 010306 general physics, Physics, DEEP-INELASTIC-SCATTERING, Range (particle radiation), F-2(P), 010308 nuclear & particles physics, Scattering, Structure function, HERA, 3. Good health, chemistry, Physics::Accelerator Physics, High Energy Physics::Experiment, Astrophysics::Earth and Planetary Astrophysics, Atomic physics, Storage ring
Abstract: A measurement of the proton spin structure function g1p(x,Q^2) in deep-inelastic scattering is presented. The data were taken with the 27.6 GeV longitudinally polarised positron beam at HERA incident on a longitudinally polarised pure hydrogen gas target internal to the storage ring. The kinematic range is 0.021, Comment: 7 pages, 3 figures, 1 table, RevTeX latex
Published: 1998

38. Investigations of azimuthal asymmetry in semi-inclusive leptoproduction

Author: Nicola Bianchi, K. A. Oganessyan, P. Di Nezza, and H. Avakian
Subjects: Physics, Mathematics::Functional Analysis, Particle physics, Physics and Astronomy (miscellaneous), High Energy Physics::Lattice, High Energy Physics::Phenomenology, FOS: Physical sciences, Nonlinear Sciences::Chaotic Dynamics, High Energy Physics - Phenomenology, Mathematics::Group Theory, High Energy Physics - Phenomenology (hep-ph), Azimuthal asymmetry, High Energy Physics::Experiment, Engineering (miscellaneous)
Abstract: We consider the azimuthal asymmetries in semi-inclusive deep inelastic leptoproduction arising due to both perturbative and nonperturbative effects at HERMES energies and show that the $k_T^2/Q^2$ order corrections to $< \cos��>$ and $< \cos2��>$ are significant. We also reconsider the results of perturbative effects for $< \cos��>$ at large momentum transfers \cite{A1} using the more recent sets of scale-dependent distribution and fragmentation functions, which bring up to $18{%}$ difference in $< \cos��>$. In the same approach we calculate the $< \cos2��>$ as well., 8 pages, LaTeX, 6 PS figures, final version, to appear in EPJC
Published: 1998

39. The HERMES spectrometer

Author: K. Ackerstaff, A. Airapetian, N. Akopov, M. Amarian, V. Andreev, E.C. Aschenauer, R. Avakian, H. Avakian, A. Avetissian, B. Bains, S. Barrow, W. Beckhusen, M. Beckmann, St. Belostotski, E. Belz, Th. Benisch, S. Bernreuther, N. Bianchi, J. Blouw, H. Böttcher, A. Borissov, J. Brack, B. Braun, B. Bray, S. Brons, W. Brückner, A. Brüll, H.J. Bulten, G.P. Capitani, P. Carter, P. Chumney, E. Cisbani, S. Clark, S. Colilli, H. Coombes, G.R. Court, P. Delheij, E. Devitsin, C.W. de Jager, E. De Sanctis, D. De Schepper, P.K.A. de Witt Huberts, P. Di Nezza, M. Doets, M. Düren, A. Dvoredsky, G. Elbakian, J. Emerson, A. Fantoni, A. Fechtchenko, M. Ferstl, D. Fick, K. Fiedler, B.W. Filippone, H. Fischer, H.T. Fortune, J. Franz, S. Frullani, M.-A. Funk, N.D. Gagunashvili, P. Galumian, H. Gao, Y. Gärber, F. Garibaldi, G. Gavrilov, P. Geiger, V. Gharibyan, V. Giordjian, F. Giuliani, A. Golendoukhin, B. Grabowski, G. Graw, O. Grebeniouk, P. Green, G. Greeniaus, M. Gricia, C. Grosshauser, A. Gute, J.P. Haas, K. Hakelberg, W. Haeberli, J.-O. Hansen, D. Hasch, O. Hausser, R. Henderson, Th. Henkes, R. Hertenberger, Y. Holler, R.J. Holt, H. Ihssen, A. Izotov, M. Iodice, H.E. Jackson, A. Jgoun, C. Jones, R. Kaiser, J. Kelsey, E. Kinney, M. Kirsch, A. Kisselev, P. Kitching, H. Kobayashi, E. Kok, K. Königsmann, M. Kolstein, H. Kolster, W. Korsch, S. Kozlov, V. Kozlov, R. Kowalczyk, L. Kramer, B. Krause, A. Krivchitch, V.G. Krivokhijine, M. Kueckes, P. Kutt, G. Kyle, W. Lachnit, R. Langstaff, W. Lorenzon, M. Lucentini, A. Lung, N. Makins, V. Maleev, S.I. Manaenkov, K. Martens, A. Mateos, K. McIlhany, R.D. McKeown, F. Meißner, F. Menden, D. Mercer, A. Metz, N. Meyners, O. Mikloukho, C.A. Miller, M.A. Miller, R. Milner, V. Mitsyn, G. Modrak, J. Morton, A. Most, R. Mozzetti, V. Muccifora, A. Nagaitsev, Y. Naryshkin, A.M. Nathan, F. Neunreither, M. Niczyporuk, W.-D. Nowak, M. Nupieri, P. Oelwein, H. Ogami, T.G. O’Neill, R. Openshaw, V. Papavassiliou, S.F. Pate, S. Patrichev, M. Pitt, H.J. Plett, H.R. Poolman, S. Potashov, D. Potterveld, B. Povh, V. Prahl, G. Rakness, V. Razmyslovich, R. Redwine, A.R. Reolon, R. Ristinen, K. Rith, H.O. Roloff, G. Röper, P. Rossi, S. Rudnitsky, H. Russo, D. Ryckbosch, Y. Sakemi, F. Santavenere, I. Savin, F. Schmidt, H. Schmitt, G. Schnell, K.P. Schüler, A. Schwind, T.-A. Shibata, T. Shin, B. Siebels, A. Simon, K. Sinram, W.R. Smythe, J. Sowinski, M. Spengos, K. Sperber, E. Steffens, J. Stenger, J. Stewart, F. Stock, U. Stößlein, M. Sutter, H. Tallini, S. Taroian, A. Terkulov, D. Thiessen, B. Tipton, V. Trofimov, A. Trudel, M. Tytgat, G.M. Urciuoli, R. Van de Vyver, J.F.J. van den Brand, G. van der Steenhoven, J.J. van Hunen, D. van Westrum, A. Vassiliev, M.C. Vetterli, M.G. Vincter, E. Volk, W. Wander, T.P. Welch, S.E. Williamson, T. Wise, G. Wöbke, K. Woller, S. Yoneyama, K. Zapfe-Düren, T. Zeuli, H. Zohrabian, and (Astro)-Particles Physics
Subjects: HERMES experiment, Nuclear and High Energy Physics, Particle physics, semi-inclusive scattering, (e, Physics::Instrumentation and Detectors, Cherenkov detector, CALORIMETERS, FOS: Physical sciences, deep inelastic lepton scattering, (e,e''h), Tracking (particle physics), Particle identification, High Energy Physics - Experiment, INORGANIC MATERIALS, law.invention, High Energy Physics - Experiment (hep-ex), e''h), GAS-MIXTURES, law, Nuclear Experiment, Instrumentation, Physics, Calorimeter (particle physics), Spectrometer, PERFORMANCE, magnetic spectrometer, Deep inelastic scattering, Transition radiation detector, CHAMBERS, High Energy Physics::Experiment
Abstract: The HERMES experiment is collecting data on inclusive and semi-inclusive deep inelastic scattering of polarised positrons from polarised targets of H, D, and He. These data give information on the spin structure of the nucleon. This paper describes the forward angle spectrometer built for this purpose. The spectrometer includes numerous tracking chambers (micro-strip gas chambers, drift and proportional chambers) in front of and behind a 1.3 T.m magnetic field, as well as an extensive set of detectors for particle identification (a lead-glass calorimeter, a pre-shower detector, a transition radiation detector, and a threshold Cherenkov detector). Two of the main features of the spectrometer are its good acceptance and identification of both positrons and hadrons, in particular pions. These characteristics, together with the purity of the targets, are allowing HERMES to make unique contributions to the understanding of how the spins of the quarks contribute to the spin of the nucleon., 37 pages, 32 figures, 4 tables
Published: 1998

40. Measurement of the neutron spin structure function g with a polarized 3He internal target

Author: K. Ackerstaff, A. Airapetian, I. Akushevich, N. Akopov, M. Amarian, E.C. Aschenauer, R. Avakian, H. Avakian, A. Avetissian, B. Bains, S. Barrow, M. Beckmann, S. Belostotski, J.E. Belz, Th. Benisch, S. Bernreuther, N. Bianchi, S. Blanchard, J. Blouw, H. Böttcher, A. Borissov, J. Brack, B. Braun, B. Bray, W. Brückner, A. Brüll, E.E.W. Bruins, H.J. Bulten, G.P. Capitani, P. Carter, E. Cisbani, G.R. Court, P.P.J. Delheij, E. Devitsin, C.W. de Jager, E. De Sanctis, D. De Schepper, P.K.A. de Witt Huberts, M. Düren, A. Dvoredsky, G. Elbakian, J. Emerson, A. Fantoni, A. Fechtchenko, M. Ferstl, D. Fick, K. Fiedler, B.W. Filippone, H. Fischer, H.T. Fortune, J. Franz, S. Frullani, M.-A. Funk, N.D. Gagunashvili, P. Galumian, H. Gao, Y. Gärber, F. Garibaldi, P. Geiger, V. Gharibyan, A. Golendoukhin, G. Graw, O. Grebeniouk, P.W. Green, L.G. Greeniaus, C. Grosshauser, A. Gute, V. Gyurjyan, J.P. Haas, W. Haeberli, J.-O. Hansen, D. Hasch, O. Häusser, R.S. Henderson, Th. Henkes, R. Hertenberger, Y. Holler, R.J. Holt, H. Ihssen, M. Iodice, A. Izotov, H.E. Jackson, A. Jgoun, C. Jones, R. Kaiser, E. Kinney, M. Kirsch, A. Kisselev, P. Kitching, N. Koch, K. Königsmann, M. Kolstein, H. Kolster, W. Korsch, V. Kozlov, L.H. Kramer, B. Krause, V.G. Krivokhijine, M. Kückes, G. Kyle, W. Lachnit, W. Lorenzon, A. Lung, N.C.R. Makins, S.I. Manaenkov, F.K. Martens, J.W. Martin, A. Mateos, K. McIlhany, R.D. McKeown, F. Meissner, D. Mercer, A. Metz, N. Meyners, O. Mikloukho, C.A. Miller, M.A. Miller, R.G. Milner, V. Mitsyn, A. Most, R. Mozzetti, V. Muccifora, A. Nagaitsev, Y. Naryshkin, A.M. Nathan, F. Neunreither, M. Niczyporuk, W.-D. Nowak, M. Nupieri, P. Oelwein, H. Ogami, T.G. O'Neill, R. Openshaw, V. Papavassiliou, S.F. Pate, M. Pitt, S. Potashov, D.H. Potterveld, B. Povh, G. Rakness, R. Redwine, A.R. Reolon, R. Ristinen, K. Rith, G. Röper, H. Roloff, P. Rossi, S. Rudnitsky, M. Ruh, D. Ryckbosch, Y. Sakemi, I. Savin, K.P. Schüller, A. Schwind, T.-A. Shibata, T. Shin, A. Simon, K. Sinram, W.R. Smythe, J. Sowinski, M. Spengos, E. Steffens, J. Stenger, J. Stewart, F. Stock, U. Stoesslein, M. Sutter, H. Tallini, S. Taroian, A. Terkulov, D.M. Thiessen, B. Tipton, A. Trudel, M. Tytgat, G.M. Urciuoli, R. Van de Vyver, J.F.J. van den Brand, G. van der Steenhoven, M.C. Vetterli, E. Volk, W. Wander, T.P. Welch, S.E. Williamson, T. Wise, T. Wölfel, K. Zapfe-Düren, H. Zohrabian, and R. Zurmühle
Subjects: Physics, HERMES experiment, Nuclear and High Energy Physics, Range (particle radiation), 010308 nuclear & particles physics, Astrophysics::Cosmology and Extragalactic Astrophysics, HERA, Spin structure, Deep inelastic scattering, 01 natural sciences, Nuclear physics, Positron, 0103 physical sciences, High Energy Physics::Experiment, Neutron, Atomic physics, 010306 general physics, Spin-½
Abstract: Results are reported from the HERMES experiment at HERA on a measurement of the neutron spin structure function g1n(x, Q2) in deep inelastic scattering using 27.5 GeV longitudinally polarized positrons incident on a polarized 3He internal gas target. The data cover the kinematic range 0.023
Published: 1997

41. Differential photoproduction cross sections of theΣ0(1385),Λ(1405), andΛ(1520)

Author: H. Y. Lu, Jie Zhang, H. Avakian, M. F. Vineyard, R. Fersch, N. Guler, M. J. Amaryan, N. K. Walford, S. Fegan, H. Voskanyan, H. Seraydaryan, J. P. Ball, D. S. Carman, I. Zonta, R. De Vita, W. J. Briscoe, E. Pasyuk, E. Voutier, Friedrich Klein, H. Moutarde, I. Niculescu, Brian Raue, K. L. Giovanetti, Y. G. Sharabian, A. Kubarovsky, S. Anefalos Pereira, Larry Weinstein, A. Deur, R. A. Schumacher, F. Sabatié, B. Vernarsky, V. P. Kubarovsky, D. Doughty, S. Tkachenko, P. Eugenio, L. Guo, G. Niculescu, Andrew Puckett, Martin K. Mayer, O. Pogorelko, D. Adikaram, W. K. Brooks, D. Heddle, D. Protopopescu, M. Guidal, S. Pozdniakov, S. Park, E. Munevar, S. Niccolai, S. Chandavar, E. Seder, B. S. Ishkhanov, E. De Sanctis, C. E. Taylor, J. J. Phillips, P. Rossi, M. S. Saini, Michael Wood, M. Aghasyan, Z. W. Zhao, David M. Keller, D. I. Sober, M. Holtrop, S. Stepanyan, I. J. D. MacGregor, H. Hakobyan, D. Ho, V. Crede, Y. Ilieva, Kei Moriya, C. A. Meyer, G. V. Fedotov, E. Golovatch, C. Hanretty, Nicholas Zachariou, M. Khandaker, M. Contalbrigo, C. S. Nepali, Luciano Pappalardo, S. Strauch, D. P. Watts, R. A. Montgomery, S. Lewis, M. D. Mestayer, B. McKinnon, J. A. Fleming, O. Cortes, T. Mineeva, D. Rimal, P. Stoler, M. Taiuti, E. L. Isupov, W. Tang, J. Bono, P. Nadel-Turonski, Ye Tian, Michael L. Williams, K. P. Adhikari, B. Dey, M. Osipenko, Diane Schott, G. Rosner, R. Nasseripour, A. I. Ostrovidov, K. Park, S. Boiarinov, K. Hicks, I. Bedlinskiy, D. G. Ireland, D. Martinez, Volker D. Burkert, A. S. Biselli, M. Mirazita, Barry Ritchie, F. X. Girod, A. Celentano, R. W. Gothe, Sergey Kuleshov, J. T. Goetz, V. Mokeev, W. Gohn, N. Gevorgyan, V. Batourine, C. Djalali, J. W. Price, S. Koirala, R. Paremuzyan, Lorenzo Zana, E. Phelps, S. Pisano, H. S. Jo, Gerard Gilfoyle, C. Salgado, D. Sokhan, Hovanes Egiyan, C. Munoz Camacho, R. P. Bennett, P. Collins, N. A. Baltzell, K. A. Griffioen, S. Taylor, Avraham Klein, M. Ungaro, M. Ripani, Michael Dugger, K. Joo, M. Bellis, R. Dupre, M. Battaglieri, S. Procureur, George Davey Smith, A. D'Angelo, L. El Fassi, M. E. McCracken, K. Livingston, and N. Dashyan
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Current (mathematics), 010308 nuclear & particles physics, Theoretical models, Hyperon, Sigma, Lambda, 01 natural sciences, Nuclear physics, Isospin, 0103 physical sciences, Effective lagrangian, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Differential (mathematics)
Abstract: We report the exclusive photoproduction cross sections for the Sigma(1385), Lambda(1405), and Lambda(1520) in the reactions gamma + p -> K+ + Y* using the CLAS detector for energies from near the respective production thresholds up to a center-of-mass energy W of 2.85 GeV. The differential cross sections are integrated to give the total exclusive cross sections for each hyperon. Comparisons are made to current theoretical models based on the effective Lagrangian approach and fitted to previous data. The accuracy of these models is seen to vary widely. The cross sections for the Lambda(1405) region are strikingly different for the Sigma+pi-, Sigma0 pi0, and Sigma- pi+ decay channels, indicating the effect of isospin interference, especially at W values close to the threshold.
Published: 2013

42. Demonstration of a novel technique to measure two-photon exchange effects in elastice±pscattering

Author: R. P. Bennett, P. Eugenio, J. Bono, N. A. Baltzell, K. A. Griffioen, Andrew Puckett, S. Strauch, Martin K. Mayer, H. Y. Lu, M. MacCormick, A. Deur, R. Paremuzyan, M. Battaglieri, M. S. Saini, I. Zonta, H. Egiyan, Gerard Gilfoyle, R. De Vita, D. Sokhan, I. Niculescu, J. T. Goetz, B. McKinnon, P. Collins, S. Tkachenko, E. Seder, M. Mirazita, E. Phelps, S. Anefalos Pereira, L. Guo, Z. W. Zhao, G. Rosner, R. Nasseripour, N. Gevorgyan, S. Chandavar, W. Gohn, D. Ho, V. Batourine, Kei Moriya, C. E. Taylor, William Brooks, S. E. Kuhn, O. Cortes, V. P. Kubarovsky, G. V. Fedotov, E. L. Isupov, Ye Tian, J. A. Fleming, S. Park, J. Zhang, Andrei Afanasev, E. De Sanctis, E. Golovatch, O. Pogorelko, S. Boiarinov, A. Celentano, R. Dupre, R. W. Gothe, P. Rossi, M. Aghasyan, R. A. Schumacher, C. Munoz Camacho, K. P. Adhikari, Lorenzo Zana, H. Avakian, J. Lachniet, D. I. Sober, H. Hakobyan, C. Hanretty, S. Procureur, N. Harrison, Maryam Moteabbed, E. Munevar, B. S. Ishkhanov, V. Crede, C. Salgado, N. K. Walford, M. Ungaro, H. Voskanyan, R. A. Montgomery, Chaden Djalali, Elton Smith, M. R. Niroula, H. Seraydaryan, Y. G. Sharabian, A. Kubarovsky, S. Lewis, F. Sabatié, S. Stepanyan, G. Niculescu, W. J. Briscoe, I. Bedlinskiy, H. S. Jo, K. Joo, T. Mineeva, J. J. Phillips, George Davey Smith, Dustin Keller, S. Fegan, S. Pisano, I. J. D. MacGregor, S. Koirala, A. Kim, W. Tang, Michael Wood, M. Contalbrigo, A. D'Angelo, M. Osipenko, K. Hafidi, Victor Mokeev, K. Hicks, D. Martinez, F. X. Girod, N. Dashyan, L. El Fassi, J. W. Price, D. Protopopescu, P. Nadel-Turonski, S. Pozdniakov, E. Voutier, Diane Schott, A. I. Ostrovidov, K. Park, D. G. Ireland, N. Guler, Volker D. Burkert, A. S. Biselli, Y. Ilieva, Nicholas Zachariou, J. P. Ball, D. Rimal, R. G. Fersch, D. S. Carman, P. L. Cole, D. Doughty, S. Niccolai, D. Heddle, M. J. Amaryan, H. Moutarde, K. L. Giovanetti, Sergey Kuleshov, D. Adikaram, Larry Weinstein, M. Guidal, M. Holtrop, Luciano Pappalardo, M. Khandaker, C. E. Hyde, Friedrich Klein, J. Arrington, Brian Raue, and M. Ripani
Subjects: Elastic scattering, Physics, Nuclear and High Energy Physics, Photon, Proton, 010308 nuclear & particles physics, Scattering, Electron, 01 natural sciences, Nuclear physics, Positron, 0103 physical sciences, Physics::Accelerator Physics, High Energy Physics::Experiment, Atomic physics, 010306 general physics, Electron scattering, Beam (structure)
Abstract: Background: The discrepancy between proton electromagnetic form factors extracted using unpolarized and polarized scattering data is believed to be a consequence of two-photon exchange (TPE) effects. However, the calculations of TPE corrections have significant model dependence, and there is limited direct experimental evidence for such corrections. Purpose: The TPE contributions depend on the sign of the lepton charge in e(+/-)p scattering, but the luminosities of secondary positron beams limited past measurement at large scattering angles, where the TPE effects are believe to be most significant. We present the results of a new experimental technique for making direct e(+/-)p comparisons, which has the potential to make precise measurements over a broad range in Q(2) and scattering angles. Methods: We use the Jefferson Laboratory electron beam and the Hall B photon tagger to generate a clean but untagged photon beam. The photon beam impinges on a converter foil to generate a mixed beam of electrons, positrons, and photons. A chicane is used to separate and recombine the electron and positron beams while the photon beam is stopped by a photon blocker. This provides a combined electron and positron beam, with energies from 0.5 to 3.2 GeV, which impinges on a liquid hydrogen target. The large acceptance CLAS detector is used to identify and reconstruct elastic scattering events, determining both the initial lepton energy and the sign of the scattered lepton. Results: The data were collected in two days with a primary electron beam energy of only 3.3 GeV, limiting the data from this run to smaller values of Q(2) and scattering angle. Nonetheless, this measurement yields a data sample for e(+/-)p with statistics comparable to those of the best previous measurements. We have shown that we can cleanly identify elastic scattering events and correct for the difference in acceptance for electron and positron scattering. Because we ran with only one polarity for the chicane, we are unable to study the difference between the incoming electron and positron beams. This systematic effect leads to the largest uncertainty in the final ratio of positron to electron scattering: R = 1.027 +/- 0.005 +/- 0.05 for = 0.206 GeV2 and 0.830
Published: 2013

43. Separated structure functions for exclusiveK+ΛandK+Σ0electroproduction at 5.5 GeV measured with CLAS

Author: N. A. Baltzell, E. De Sanctis, M. Aghasyan, H. Y. Lu, M. D. Mestayer, S. Strauch, G. Charles, D. I. Sober, O. Cortes, E. L. Isupov, Ye Tian, S. Procureur, Y. Prok, M. Ungaro, Eugene Pasyuk, D. P. Watts, P. Stoler, F. X. Girod, S. Boiarinov, M. Anghinolfi, H. Seraydaryan, M. Contalbrigo, V. P. Kubarovsky, D. Doughty, C. Hanretty, A. Fradi, Y. G. Sharabian, M. Ripani, I. Niculescu, R. De Vita, A. El Alaoui, V. Mokeev, O. Pogorelko, K. Joo, J. T. Goetz, K. Hicks, D. Heddle, J. W. Price, S. Anefalos Pereira, M. Y. Gabrielyan, Andrew Puckett, Martin K. Mayer, Dustin Keller, C. Munoz Camacho, J. P. Ball, S. Lewis, R. A. Schumacher, D. S. Carman, S. Pisano, B. McKinnon, M. S. Saini, S. Koirala, Sergey Kuleshov, R. Dupre, Nicholas Zachariou, D. Rimal, P. L. Cole, C. Djalali, Michael Wood, I. Bedlinskiy, S. Chandavar, M. Mirazita, E. Phelps, K. Hafidi, S. Park, M. Battaglieri, N. Gevorgyan, George Davey Smith, S. Tkachenko, V. Batourine, E. Voutier, E. Seder, L. Guo, Lorenzo Zana, I. Zonta, Diane Schott, H. Avakian, A. I. Ostrovidov, K. Park, R. Nasseripour, K. Livingston, J. A. Fleming, W. Kim, N. K. Walford, T. Mineeva, N. Harrison, A. D'Angelo, S. Stepanyan, H. Hakobyan, H. S. Jo, E. Munevar, C. A. Meyer, H. Voskanyan, R. Paremuzyan, G. V. Fedotov, I. I. Strakovsky, B. Guegan, Avraham Klein, K. A. Griffioen, D. G. Ireland, Y. Ilieva, Jie Zhang, G. Niculescu, S. Fegan, W. J. Briscoe, J. Bono, P. Nadel-Turonski, V. Crede, C. Salgado, P. Eugenio, J. J. Phillips, L. El Fassi, A. Deur, M. Taiuti, K. P. Adhikari, D. Sokhan, S. Niccolai, William Brooks, Volker D. Burkert, A. S. Biselli, R. Fersch, Y. Mao, S. S. Stepanyan, P. Khetarpal, I. J. D. MacGregor, N. Dashyan, C. S. Nepali, C. E. Taylor, R. A. Montgomery, N. A. Saylor, A. Trivedi, N. D. Kvaltine, H. Baghdasaryan, W. Tang, P. Rossi, A. Celentano, R. W. Gothe, Z. W. Zhao, A. Kubarovsky, M. Osipenko, B. Vernarsky, D. Ho, D. Adikaram, M. Khandaker, M. Guidal, B. S. Ishkhanov, D. Protopopescu, D. Martinez, S. Pozdniakov, W. Gohn, M. Holtrop, Luciano Pappalardo, M. J. Amaryan, H. Moutarde, K. L. Giovanetti, G. Rosner, Larry Weinstein, F. Sabatié, G. Ricco, Friedrich Klein, Brian Raue, and A. Kim
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Structure function, Hyperon, Sigma, Polarization (waves), Lambda, 01 natural sciences, Baryon, Nuclear physics, Pion, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics
Abstract: We report measurements of the exclusive electroproduction of K{sup +}{Lambda} and K{sup +}{Sigma}{sup 0} final states from an unpolarized proton target using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The separated structure functions {sigma}{sub U}, {sigma}{sub LT}, {sigma}{sub TT}, and {sigma}{sub LT'} were extracted from the {Phi}-dependent differential cross sections acquired with a longitudinally polarized 5.499~GeV electron beam. The data span a broad range of momentum transfers Q{sup 2} from 1.4 to 3.9 GeV{sup 2}, invariant energy W from threshold to 2.6 GeV, and nearly the full center-of-mass angular range of the kaon. The separated structure functions provide an unprecedented data sample, which in conjunction with other meson photo- and electroproduction data, will help to constrain the higher-level analyses being performed to search for missing baryon resonances.
Published: 2013

44. Performance of F101 radiation resistant lead glass shower counters

Author: M. Nupieri, V. Giourdjian, R. Avakian, A. R. Reolon, A. Avetissian, B. W. Filippone, M. Amarian, G. P. Capitani, M. Kolstein, A. Airapetian, N. Akopov, M. Doets, Alessandra Fantoni, P. Galumian, Valeria Muccifora, S. Taroian, A. Simon, Th. Henkes, V. Garibian, E. De Sanctis, P. Rossi, Nicola Bianchi, J. F. J. van den Brand, R. Mozzetti, B. Bray, H. Avakian, A. Lung, and (Astro)-Particles Physics
Subjects: Physics, Nuclear and High Energy Physics, Range (particle radiation), Radiation resistant, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Resolution (electron density), Linearity, Nuclear physics, Lead glass, Optics, DESIGN, ELECTROMAGNETIC CALORIMETER, visual_art, visual_art.visual_art_medium, SPECTROMETER, High Energy Physics::Experiment, business, Instrumentation, Cherenkov radiation
Abstract: The performance of F101 lead glass as a Cherenkov radiation material was studied. A 3 x 3 array of 9 x 9 cm(2) and 50 cm length counters showed an energy resolution of approximate to 5.0%/root E(GeV), good linearity in the energy range from 1 to 25 GeV and pi(-)/e rejection of approximate to 4 x 10(-4).
Published: 1996

45. Transverse Momentum Dependent Parton Distribution/Fragmentation Functions at an Electron-Ion Collider

Author: M. Contalbrigo, Matthias Burkardt, J. C. Peng, Jian-Wei Qiu, Minghui Liu, Xin Qian, Daniël Boer, Dipangkar Dutta, Q. J. Ye, Zhong-Bo Kang, Peter Schweitzer, Z. T. Liang, H. Avakian, P. Rossi, X. Zhan, G. Laskaris, A. Prokudin, R. D. McKeown, Leonard Gamberg, J. Soffer, J.P. Chen, N. C. R. Makins, Cynthia Keppel, J. Huang, Y.-H. Zhang, Yujie Qiang, Bernhard Musch, E. Cisbani, J. Zhou, Feng Yuan, Q. Ye, W. Zheng, Donald Crabb, Franco Bradamante, Vincent Sulkosky, Mauro Anselmino, Yi Wang, Zein-Eddine Meziani, Andreas Metz, Haiyan Gao, D. Hasch, M. Huang, and Bo-Wen Xiao
Subjects: Quark, Particle physics, Nuclear and High Energy Physics, media_common.quotation_subject, FRAGMENTATION FUNCTIONS, Hadron, Nuclear Theory, FOS: Physical sciences, Parton, DRELL-YAN PROCESSES, Asymmetry, law.invention, High Energy Physics - Experiment, DEEP-INELASTIC SCATTERING, HARD-SCATTERING, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), law, Nuclear Experiment (nucl-ex), Collider, PION ELECTROPRODUCTION, Nuclear Experiment, media_common, Spin-½, Physics, FINAL-STATE INTERACTIONS, High Energy Physics::Phenomenology, SINGLE-SPIN, AZIMUTHAL ASYMMETRIES, Gluon, High Energy Physics - Phenomenology, SPIN PRODUCTION ASYMMETRIES, High Energy Physics::Experiment, HADRON STRUCTURE, Nucleon
Abstract: We present a summary of a recent workshop held at Duke University on Partonic Transverse Momentum in Hadrons: Quark Spin-Orbit Correlations and Quark-Gluon Interactions. The transverse momentum dependent parton distribution functions (TMDs), parton-to-hadron fragmentation functions, and multi-parton correlation functions, were discussed extensively at the Duke workshop. In this paper, we summarize first the theoretical issues concerning the study of partonic structure of hadrons at a future electron-ion collider (EIC) with emphasis on the TMDs. We then present simulation results on experimental studies of TMDs through measurements of single spin asymmetries (SSA) from semi-inclusive deep-inelastic scattering (SIDIS) processes with an EIC, and discuss the requirement of the detector for SIDIS measurements. The dynamics of parton correlations in the nucleon is further explored via a study of SSA in D (`D) production at large transverse momenta with the aim of accessing the unexplored tri-gluon correlation functions. The workshop participants identified the SSA measurements in SIDIS as a golden program to study TMDs in both the sea and valence quark regions and to study the role of gluons, with the Sivers asymmetry measurements as examples. Such measurements will lead to major advancement in our understanding of TMDs in the valence quark region, and more importantly also allow for the investigation of TMDs in the sea quark region along with a study of their evolution., Comment: 44 pages 23 figures, summary of Duke EIC workshop on TMDs accepted by EPJA
Published: 2011
Full Text: View/download PDF

46. Transverse spin structure of the nucleon through target single-spin asymmetry in semi-inclusive deep-inelastic (e, e’ $ \pi^{\pm}_{}$ ) reaction at Jefferson Lab

Author: A. Prokudin, Y. J. Mao, Mauro Anselmino, C. W. de Jager, X. Jiang, J. P. Chen, B. Q. Ma, Xin Qian, E. Chudakov, Andrei Afanasev, M. Huang, Marc Schlegel, H. Avakian, Z. E. Meziani, L. Zhu, Z. G. Xiao, Paul Souder, G. D. Cates, Jen-Chieh Peng, Yujie Qiang, K. S. Kumar, E. Cisbani, F. Garibaldi, B. T. Hu, Yuzhen Ye, Leonard Gamberg, H. J. Lu, X. M. Li, and Haiyan Gao
Subjects: Quark, Physics, Particle physics, Angular momentum, media_common.quotation_subject, Nuclear Theory, General Physics and Astronomy, Deep inelastic scattering, Asymmetry, Particle identification, Nuclear physics, High Energy Physics - Phenomenology, Pion, High Energy Physics::Experiment, Neutron, Nuclear Experiment, Nucleon, media_common
Abstract: Jefferson Lab (JLab) 12 GeV energy upgrade provides a golden opportunity to perform precision studies of the transverse spin and transverse-momentum-dependent structure in the valence quark region for both the proton and the neutron. In this paper, we focus our discussion on a recently approved experiment on the neutron as an example of the precision studies planned at JLab. The new experiment will perform precision measurements of target Single Spin Asymmetries (SSA) from semi-inclusive electro-production of charged pions from a 40-cm long transversely polarized $^3$He target in Deep-Inelastic-Scattering kinematics using 11 and 8.8 GeV electron beams. This new coincidence experiment in Hall A will employ a newly proposed solenoid spectrometer (SoLID). The large acceptance spectrometer and the high polarized luminosity will provide precise 4-D ($x$, $z$, $P_T$ and $Q^2$) data on the Collins, Sivers, and pretzelocity asymmetries for the neutron through the azimuthal angular dependence. The full 2$\pi$ azimuthal angular coverage in the lab is essential in controlling the systematic uncertainties. The results from this experiment, when combined with the proton Collins asymmetry measurement and the Collins fragmentation function determined from the e$^+$e$^-$ collision data, will allow for a quark flavor separation in order to achieve a determination of the tensor charge of the d quark to a 10% accuracy. The extracted Sivers and pretzelocity asymmetries will provide important information to understand the correlations between the quark orbital angular momentum and the nucleon spin and between the quark spin and nucleon spin., Comment: 23 pages, 13 figures, minor corrections, matches published version
Published: 2011

47. Quark orbital angular momentum: can we learn about it from GPDs and TMDs?

Author: H. Avakian, Petr Zavada, A.V. Efremov, Peter Schweitzer, and Oleg Teryaev
Subjects: Quark, Physics, Angular momentum, Particle physics, Quark model, High Energy Physics - Lattice (hep-lat), High Energy Physics::Phenomenology, FOS: Physical sciences, Parton, Nucleon spin structure, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology, Distribution function, High Energy Physics - Phenomenology (hep-ph), High Energy Physics - Lattice, Transverse momentum, High Energy Physics::Experiment
Abstract: It is known how to access information on quark orbital angular momentum from generalized parton distribution functions, in a certain specified framework. It is intuitively expected, that such information can be accessed also through transverse momentum dependent distribution functions, but not known how. Now quark models provide promising hints. Recent results are reviewed., proceeding of the "4th Workshop on Exclusive Reactions at High Momentum Transfer," 18-21 May 2010, Jefferson Lab
Published: 2010

48. Measurement of Single and Double Spin Asymmetries in Deep Inelastic Pion Electroproduction with a Longitudinally Polarized Target

Author: Latifa Elouadrhiri, C. A. Meyer, K. P. Adhikari, E. Seder, K. Livingston, N. Dashyan, Y. Prok, H. S. Jo, P. Collins, P. Eugenio, M. Mayer, V. Kuznetsov, S. Niccolai, Daniel S. Carman, M. J. Amaryan, Y. Ilieva, R. G. Fersch, Z. W. Zhao, A. Deur, N. Guler, G. E. Dodge, H. Baghdasaryan, M. Guidal, H. Moutarde, J. Zhang, P. Rossi, P. Konczykowski, J. Salamanca, J. Ball, F. X. Girod, S. Park, Larry Weinstein, H. Seraydaryan, B. Vernarsky, D. Heddle, I. Niculescu, S. Procureur, D. Protopopescu, Michael Vineyard, B. Morrison, D. P. Watts, E. De Sanctis, S. Dhamija, Y. G. Sharabian, D. Martinez, S. Fegan, R. A. Schumacher, V. Crede, S. Stepanyan, R. Dickson, E. Voutier, M. Aghasyan, M. Taiuti, R. W. Gothe, B. Dey, N. Markov, H. Hakobyan, S. Anefalos Pereira, L. Guo, D. Doughty, M. Ungaro, D. Keller, R. Nasseripour, J. W. Price, S. S. Stepanyan, E. Pasyuk, M. R. Niroula, A. El Alaoui, B. A. Raue, M. Y. Gabrielyan, T. A. Forest, P. Nadel-Turonski, B. Zhao, S. Tkachenko, G. Ricco, Philip L. Cole, Avraham Klein, M. Ripani, T. Mineeva, S. S. Jawalkar, M. S. Saini, G. Rosner, G. Gavalian, D. J. Tedeschi, Friedrich Klein, I. Bedlinskiy, P. Bosted, E. Munevar, B. Moreno, M. Mirazita, M. Holtrop, C. Salgado, A. Daniel, Chaden Djalali, D. G. Crabb, S. E. Kuhn, M. E. McCracken, M. Anghinolfi, L. Casey, K. Moriya, N. Hassall, C. Hanretty, Y. Perrin, F. Sabatié, W. J. Briscoe, Victor Mokeev, K. Joo, K. L. Giovanetti, S. V. Kuleshov, H. Y. Lu, D. P. Weygand, M. Battaglieri, M. Osipenko, W. Kim, G. Niculescu, A. I. Ostrovidov, K. Park, D. G. Ireland, P. Khetarpal, Volker D. Burkert, A. S. Biselli, A. Fradi, R. De Vita, R. Suleiman, S. Pisano, K.H. Hicks, D. I. Sober, P. Stoler, K. A. Griffioen, S. Strauch, R. Paremuzyan, Gerard Gilfoyle, D. Sokhan, B. McKinnon, D. Branford, N. Gevorgyan, H. Avakian, W. K. Brooks, V. P. Kubarovsky, Annalisa D'Angelo, J. McAndrew, Michael Wood, K. Hafidi, E. L. Isupov, W. Gohn, R. Dupre, O. Pogorelko, M. Khandaker, 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, 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), 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, 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), 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, Meson, DRELL-YAN, Hadron, General Physics and Astronomy, FOS: Physical sciences, Inelastic scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, High Energy Physics - Experiment, Nuclear physics, High Energy Physics - Experiment (hep-ex), Pion, DEPENDENCE, CLAS, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], SCATTERING, DISTRIBUTIONS, Nuclear Experiment (nucl-ex), 010306 general physics, FINAL-STATE INTERACTIONS, TRANSVERSE-MOMENTUM, AZIMUTHAL ASYMMETRIES, DRELL-YAN, SCATTERING, DISTRIBUTIONS, QUARK, DEPENDENCE, CLAS, QCD, Nuclear Experiment, Spin-½, Physics, FINAL-STATE INTERACTIONS, 010308 nuclear & particles physics, QUARK, TRANSVERSE-MOMENTUM, Deep inelastic scattering, AZIMUTHAL ASYMMETRIES, QCD, Physics::Accelerator Physics, High Energy Physics::Experiment, Nucleon, Lepton
Abstract: We report the first measurement of the transverse momentum dependence of double-spin asymmetries in semi-inclusive production of pions in deep-inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Jefferson Lab (JLab). Modulations of single spin asymmetries over the azimuthal angle between lepton scattering and hadron production planes phi have been measured over a wide kinematic range in Bjorken x and virtual photon squared four-momentum Q(2). A significant nonzero sin2 phi single spin asymmetry was observed for the first time indicating strong spin-orbit correlations for transversely polarized quarks in the longitudinally polarized proton.
Published: 2010

49. Precise Measurement of the Neutron Magnetic Form FactorGMnin the Few-GeV2Region

Author: R. J. Feuerbach, J. P. Cummings, L. C. Smith, E. Munevar, R. De Masi, D. Keller, M. Kossov, B. S. Ishkhanov, I. Popa, K. S. Egiyan, G. Ricco, K. Mikhailov, L. Cheng, M. Khandaker, M. Garçon, J. Shaw, Michael Wood, P. Nadel-Turonski, Nikolay Shvedunov, M. R. Niroula, K. Hafidi, R. Nasseripour, S. McAleer, Friedrich Klein, B. P. Quinn, Brian Raue, V. S. Serov, L. Casey, F. X. Girod, Susan Taylor, Marco A. Huertas, M. Lowry, V. Sapunenko, D. P. Watts, L. C. Dennis, B. E. Bonner, Hartmuth Arenhövel, Dinko Pocanic, H. Egiyan, R. G. Fersch, H. Avakian, D. Doughty, B. B. Niczyporuk, G. S. Adams, S. Park, D. Sharov, N. Kalantarians, P. L. Cole, Sylvain Bouchigny, Sabine Jeschonnek, R. C. Minehart, Kei Moriya, D. Heddle, P. Rossi, J. Lachniet, H. G. Juengst, C. A. Meyer, N. Pivnyuk, K. Joo, W. J. Briscoe, B. L. Berman, A. Tkabladze, G. V. Fedotov, E. Pasyuk, D. Rowntree, A. Coleman, L. M. Qin, M. Y. Gabrielyan, S. E. Kuhn, S. A. Dytman, V. Crede, Y. Ilieva, J. R. Calarco, T. Mineeva, J. W. Price, M. J. Amaryan, C. Paterson, S. Strauch, M. MacCormick, A.V. Stavinsky, M. Klusman, I. Hleiqawi, V. P. Kubarovsky, K. P. Adhikari, S. L. Careccia, A. Empl, L. El Fassi, O. Pogorelko, B. Moreno, D. P. Weygand, J. Salamanca, R. Suleiman, M. E. McCracken, Elton Smith, K. L. Giovanetti, B. Asavapibhop, G. V. O'Rielly, Tsutomu Mibe, Larry Weinstein, Z. W. Zhao, J. W C McNabb, D. J. Tedeschi, D. Protopopescu, D. G. Jenkins, Barry Ritchie, M. Anghinolfi, James Mueller, S. Malace, S. A. Morrow, P. Rubin, I. Bedlinskiy, G. S. Mutchler, Konstantin Stopani, S. Pozdniakov, V. Gyurjyan, M. M. Ito, C. Djalali, Y. G. Sharabian, G. Rosner, T. Kageya, K. Livingston, D. S. Dale, X. Wei, R. Dickson, V. Kuznetsov, C. E. Hyde-Wright, H. Denizli, N. Guler, N. A. Baltzell, P. Mattione, K. A. Griffioen, M. S. Saini, A. V. Skabelin, P. Dragovitsch, J. Zhang, S. Barrow, E. De Sanctis, S. Niccolai, J. T. Goetz, E. Polli, H. Bagdasaryan, R. A. Miskimen, J. D. Kellie, B. McKinnon, Sergey Kuleshov, M. Bektasoglu, J. Hardie, M. Nozar, W. Kim, Laird Kramer, G. Niculescu, D. I. Sober, D. Branford, M. Guidal, R. A. Schumacher, H. Hakobyan, M. Mirazita, P. Khetarpal, C. Hanretty, J. M. Laget, M. Holtrop, Victor Mokeev, L. Graham, J. R. Johnstone, N. Gevorgyan, L. Guo, M. Ungaro, M. Osipenko, F. Sabatié, A. Daniel, K. Beard, Kalvir S. Dhuga, S. Bültmann, A. I. Ostrovidov, J. Yun, D. Cords, V. Batourine, T. A. Forest, A. Yegneswaran, A. C S Lima, A. Sandorfi, K. Park, R. Fatemi, S. Stepanyan, A. V. Vlassov, D. G. Ireland, Volker D. Burkert, A. S. Biselli, J. Pierce, Avraham Klein, B. Zhao, J. Langheinrich, R. De Vita, A. Fradi, S. S. Stepanyan, S. A. Philips, William Brooks, N. Markov, P. Konczykowski, B. E. Stokes, J. J. Manak, S. Anefalos Pereira, G. E. Dodge, H. Y. Lu, N. Dashyan, Maryam Moteabbed, P. V. Degtyarenko, K. V. Dharmawardane, I. Niculescu, D. Lawrence, D. Schott, F. W. Hersman, M. Battaglieri, N. Baillie, P. Stoler, K. Hicks, G. Asryan, O. P. Dzyubak, R. A. Niyazov, P. Corvisiero, R. Bradford, B. A. Mecking, K. Lukashin, E. Wolin, Gerard Gilfoyle, M. Guillo, D. Sokhan, W. Gohn, N. Hassall, M. Bellis, E. Golovatch, J. P. Ball, J. Hu, Y. Prok, D. S. Carman, S. Dhamija, M. D. Mestayer, L. Elouadrhiri, I. I. Strakovsky, E. L. Isupov, R. W. Gothe, G. Gavalian, S. Tkachenko, A. Deur, Michael L. Williams, J. Kuhn, N. Benmouna, J. P. Santoro, Andrei Afanasev, M. Ripani, D. G. Crabb, K. Y. Kim, Roy Thompson, Cynthia Marie Hadjidakis, S. Boiarinov, Michael Dugger, B. M. Preedom, Douglas Higinbotham, M. Yurov, Lorenzo Zana, H. S. Jo, C. Bookwalter, C. Salgado, Kwangsoo Kim, G. Riccardi, P. Eugenio, A. Starostin, M. Taiuti, Michael Vineyard, and P. Collins
Subjects: Physics, 010308 nuclear & particles physics, Scattering, Nuclear Theory, General Physics and Astronomy, Scintillator, 7. Clean energy, 01 natural sciences, Nuclear physics, Dipole, Deuterium, 0103 physical sciences, Magnetic form factor, Neutron detection, High Energy Physics::Experiment, Neutron, Nuclear Experiment, 010306 general physics, Electron scattering
Abstract: The neutron elastic magnetic form factor was extracted from quasielastic electron scattering on deuterium over the range Q;{2}=1.0-4.8 GeV2 with the CLAS detector at Jefferson Lab. High precision was achieved with a ratio technique and a simultaneous in situ calibration of the neutron detection efficiency. Neutrons were detected with electromagnetic calorimeters and time-of-flight scintillators at two beam energies. The dipole parametrization gives a good description of the data.
Published: 2009

50. Spin-Orbit Correlations in Kaon SIDIS at JLab

Author: H. Avakian, K. Hafidi, Donald G. Crabb, Yelena Prok, Matt Poelker, Simonetta Liuti, Donal B. Day, and Xiaochao Zheng
Subjects: Quark, Physics, Particle physics, media_common.quotation_subject, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Electron, Deep inelastic scattering, Helicity, Asymmetry, Particle identification, Nuclear physics, Pion, High Energy Physics::Experiment, Nuclear Experiment, media_common
Abstract: We present studies of the transverse momentum dependence of valence quark transverse and longitudinal spin distributions through measurements of spin‐azimuthal asymmetries in Semi‐Inclusive Deep Inelastic Scattering (SIDIS) of kaons using the upgraded JLab 11 GeV polarized electron beam and the CLAS12 detector with longitudinally polarized proton and deuteron targets. Measurements with kaons are complementary to measurements with pions and will provide additional information on the Collins fragmentation mechanism. The PT dependence of the double spin asymmetry provides additional information on the flavor and polarization dependence of transverse‐momentum‐dependent helicity distributions of quarks, which provides complementary to the Single‐Spin Asymmetry (SSA) measurements access to spin‐orbit correlations. The large acceptance of CLAS12 would allow simultaneous detection of scattered electrons and leading hadrons, providing information on the struck quark’s flavor and transverse momentum.
Published: 2009

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