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

Author

F. Cao, W. Phelps, M. Guidal, E. Pasyuk, N. Dashyan, P. Lenisa, Andrea Celentano, M. Holtrop, S. Procureur, W. Gohn, S. E. Kuhn, G. Charles, M. J. Amaryan, H. S. Jo, H. Y. Lu, H. Voskanyan, B. McKinnon, Iu. Skorodumina, Friedrich Klein, Z. W. Zhao, A. I. Ostrovidov, R. A. Montgomery, Y. Prok, F. Sabatié, David M. Keller, Maxime Defurne, B. Guegan, K. A. Griffioen, H. Hakobyan, P. Stoler, A. Kim, M. Mirazita, A. El Alaoui, A. Filippi, N. Markov, A. Fradi, Latifa Elouadrhiri, X. Wei, G. Rosner, Taya Chetry, C. A. Meyer, I. Balossino, N. Gevorgyan, S. Johnston, K. L. Giovanetti, E. L. Isupov, G. V. Fedotov, K. Hicks, Y. Ghandilyan, Nicholas Zachariou, P. Eugenio, G. Niculescu, V. Batourine, D. G. Ireland, Sergey Kuleshov, M. Ripani, A. Deur, L. Guo, T. Mineeva, K. P. Adhikari, J. A. Tan, M. L. Kabir, S. Niccolai, Volker D. Burkert, W. K. Brooks, D. P. Watts, B. S. Ishkhanov, S. Adhikari, A. S. Biselli, D. Heddle, M. Battaglieri, C. Gleason, M. Khachatryan, D. G. Jenkins, M. Ungaro, R. De Vita, G. Khachatryan, E. Golovatch, R. Dupre, K. Park, Y. Ilieva, Nikolaos Sparveris, L. Lanza, R. W. Gothe, W. Kim, I. Bedlinskiy, K. Livingston, C. Munoz Camacho, M. Hattawy, R. A. Schumacher, M. Osipenko, P. Rossi, W. J. Briscoe, A. D'Angelo, R. G. Fersch, V. P. Kubarovsky, P. Nadel-Turonski, D. Riser, M. Khandaker, S. Stepanyan, R. Paremuzyan, K. Hafidi, S. Bültmann, T. A. Forest, P. L. Cole, Sylvester Joosten, O. Pogorelko, S. Diehl, S. Anefalos Pereira, Avraham Klein, Nicholas M. Harrison, Gerard Gilfoyle, J. W. Price, I. J. D. MacGregor, M. Contalbrigo, Martin Wood, C. Hanretty, L. Barion, C. Salgado, M. Taiuti, J. Zhang, D. Protopopescu, Victor Mokeev, Z. Akbar, M. Garçon, E. Voutier, Y. G. Sharabian, G. Ciullo, J. P. Ball, D. S. Carman, A. Rizzo, A. Movsisyan, L. El Fassi, Zein-Eddine Meziani, M. E. McCracken, F. X. Girod, O. Cortes, S. Boiarinov, Chaden Djalali, G. D. Smith, S. Strauch, G. Gavalian, B. A. Clary, N. Hirlinger Saylor, Michael Paolone, N. A. Baltzell, K. Joo, H. Egiyan, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, CLAS, and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
electron p: deep inelastic scattering, interference: Bethe-Heitler, Nuclear and High Energy Physics, generalized parton distribution, Proton, accelerator, electron: polarized beam, Hadronic Physics and QCD, FOS: Physical sciences, Socio-culturale, parton: distribution function, Parton, Newport News CEBAF Linac, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], momentum transfer dependence, 01 natural sciences, beam: energy, High Energy Physics - Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare, x-dependence, Nuclear physics, Cross section (physics), High Energy Physics - Experiment (hep-ex), spectrometer: acceptance, High Energy Physics - Phenomenology (hep-ph), deeply virtual Compton scattering, CLAS, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Quantum chromodynamics, Physics, Spectrometer, 010308 nuclear & particles physics, Compton scattering, cross section: difference, HERA, magnetic spectrometer, photon: electroproduction, High Energy Physics - Phenomenology, kinematics, [PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph], Nucleon, channel cross section: measured, experimental results
Abstract

This paper reports the measurement of polarized and unpolarized cross sections for the ep -> e'p' reaction, which is comprised of Deeply Virtual Compton Scattering (DVCS) and Bethe-Heitler (BH) processes, at an electron beam energy of 5.88 GeV at the Thomas Jefferson National Accelerator Facility using the Large Acceptance Spectrometer CLAS. The unpolarized cross sections and polarized cross section differences have been measured over broad kinematics, 0.10 < x_B < 0.58, 1.0 < Q^2 < 4.8 GeV^2, and 0.09 < -t < 2.00 GeV^2. The results are found to be consistent with previous CLAS data, and these new data are discussed in the framework of the generalized parton distribution approach. Calculations with two widely used phenomenological models, denoted VGG and KMSC, are approximately compatible with the experimental results over a large portion of the kinematic range of the data., 27 pages, 24 figures, Accepted for publication in PRC

Published
2018
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2. The central neutron detector for CLAS12

Author

J. Peyré, B. Garillon, B. Genolini, P. Chatagnon, D. Marchand, G. Hull, M. Guidal, S. Niccolai, G. Murdoch, B. Mathon, P. Rosier, C. Theneau, J. Pouthas, B. Guegan, Julien Bettane, D. Sokhan, T. Nguyen Trung, Rong Wang, Alain Maroni, M. Imre, Michaël Josselin, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Photomultiplier, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Neutron detector, Barrel (horology), Scintillator, 01 natural sciences, 7. Clean energy, Optics, 0103 physical sciences, Neutron detection, JLab, Neutron, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010306 general physics, Nuclear Experiment, Instrumentation, Physics, Plastic scintillator, 010308 nuclear & particles physics, business.industry, Time-of-flight, Detector, Time resolution, Time of flight, Light collection, business, CLAS12
Abstract

International audience; The Central Neutron Detector, a recently constructed scintillator barrel which is used in CLAS12 at Jefferson Lab to detect 0.2–1 GeV neutrons at backwards angles, is here described. The motivations and R&D; tests leading to its final design, based on three radial layers of coupled paddles with one-side light readout by photomultipliers plus “U-turn” lightguides on the other side, are outlined. The performance of the detector, evaluated from cosmic-ray tests and simulations, which satisfies the physics requirements, is reported.

Published
2018
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3. 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
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4. Model selection for amplitude analysis

Author

Mike Williams, B. Guegan, J. R. Stevens, J. Hardin, Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Guegan, Baptiste, Hardin, John Melvin, Stevens, Justin Ryan, and Williams, Mateo S.

Subjects
Multivariate statistics, Computer science, Model selection, FOS: Physical sciences, Probability and statistics, Context (language use), Regularization (mathematics), Regression, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Amplitude, Physics - Data Analysis, Statistics and Probability, A priori and a posteriori, Instrumentation, Algorithm, Data Analysis, Statistics and Probability (physics.data-an), Mathematical Physics
Abstract

Model complexity in amplitude analyses is often a priori under-constrained since the underlying theory permits a large number of possible amplitudes to contribute to most physical processes. The use of an overly complex model results in reduced predictive power and worse resolution on unknown parameters of interest. Therefore, it is common to reduce the complexity by removing from consideration some subset of the allowed amplitudes. This paper studies a method for limiting model complexity from the data sample itself through regularization during regression in the context of a multivariate (Dalitz-plot) analysis. The regularization technique applied greatly improves the performance. An outline of how to obtain the significance of a resonance in a multivariate amplitude analysis is also provided.

Published
2015

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

Author

B. S. Ishkhanov, I. Zonta, J. Bono, P. Nadel-Turonski, X. Wei, E. De Sanctis, P. Eugenio, M. Taiuti, K. A. Griffioen, B. Garillon, Z. W. Zhao, C. E. Hyde, A. Filippi, D. Protopopescu, A. Kim, M. Garçon, S. Niccolai, A. Trivedi, Andrew Puckett, J. T. Goetz, F. X. Girod, Michael Paolone, I. I. Strakovsky, V. Crede, L. Guo, R. A. Schumacher, Sergey Kuleshov, M. Khandaker, Alessandro Rizzo, S. Chandavar, W. Tang, G. Charles, A. Deur, M. Osipenko, Latifa Elouadrhiri, Gerard Gilfoyle, Nikolaos Sparveris, M. Battaglieri, W. K. Brooks, A. Simonyan, R. De Vita, R. A. Montgomery, D. Martinez, B. Guegan, H. Hakobyan, C. Hanretty, C. E. Taylor, K. Livingston, N. Dashyan, G. V. Fedotov, S. Strauch, V. Sytnik, E. Golovatch, R. Dupre, Avraham Klein, H. S. Jo, Jie Zhang, S. Anefalos Pereira, V. Mokeev, P. Lenisa, V. P. Kubarovsky, H. S. Joo, H. Y. Lu, W. Phelps, Eugene Pasyuk, Inna Aznauryan, O. Pogorelko, S. M. Hughes, K. P. Adhikari, I. Bedlinskiy, C. Salgado, P. Roy, S. E. Kuhn, P. Peng, Hovanes Egiyan, C. Munoz Camacho, W. Kim, J. A. Fleming, M. Guidal, G. Niculescu, Yordanka Ilieva, H. Avakian, C. Djalali, K. Park, M. Ripani, I. Niculescu, B. McKinnon, P. Rossi, M. J. Amaryan, S. Joosten, G. D. Smith, M. Holtrop, Friedrich Klein, A. El Alaoui, M. Hattawy, Brian Raue, L. Zana, G. Rosner, H. Voskanyan, Nicholas Zachariou, Elton Smith, D. G. Jenkins, W. J. Briscoe, E. Seder, F. Sabatié, P. Stoler, D. P. Watts, S. Procureur, H. Moutarde, Dustin Keller, M. Ungaro, Michael Wood, K. Hicks, Y. G. Sharabian, K. Joo, O. Cortes, E. L. Isupov, Ye Tian, J. W. Price, K. L. Giovanetti, S. Fegan, Iu. Skorodumina, Larry Weinstein, D. Doughty, Y. Prok, D. S. Carman, E. Voutier, M. Contalbrigo, R. A. Badui, A. Celentano, R. W. Gothe, N. K. Walford, J. J. Phillips, I. J. D. MacGregor, A. D'Angelo, L. El Fassi, R. G. Fersch, Diane Schott, P. L. Cole, A. I. Ostrovidov, N. Gevorgyan, D. G. Ireland, H. Jiang, Volker D. Burkert, A. S. Biselli, L. Colaneri, N. Markov, and S. Pisano

Subjects
Physics, Quark, Nuclear and High Energy Physics, Particle physics, Amplitude, Isospin, Quark model, Isobar, Resonance, Invariant mass, Nucleon
Abstract

Differential cross sections of the exclusive process $ep\ensuremath{\rightarrow}{e}^{\ensuremath{'}}{\ensuremath{\pi}}^{+}n$ were measured with good precision in the range of the photon virtuality ${Q}^{2}=1.8--4.5$ ${\mathrm{GeV}}^{2}$ and the invariant mass range of the ${\ensuremath{\pi}}^{+}n$ final state $W=1.6--2.0$ GeV using the Continuous Electron Beam Accelerator Facility Large Acceptance Spectrometer. Data were collected with nearly complete coverage in the azimuthal and polar angles of the $n{\ensuremath{\pi}}^{+}$ center-of-mass system. More than 37 000 cross-section points were measured. The contributions of the isospin $I=\frac{1}{2}$ resonances $N(1675){\frac{5}{2}}^{\ensuremath{-}},N(1680){\frac{5}{2}}^{+}$, and $N(1710){\frac{1}{2}}^{+}$ were extracted at different values of ${Q}^{2}$ using a single-channel, energy-dependent resonance amplitude analysis. Two different approaches, the unitary isobar model and the fixed-$t$ dispersion relations, were employed in the analysis. We observe significant strength of the $N(1675){\frac{5}{2}}^{\ensuremath{-}}$ in the ${A}_{1/2}$ amplitude, which is in strong disagreement with quark models that predict both transverse amplitudes to be strongly suppressed. For the $N(1680){\frac{5}{2}}^{+}$ we observe a slow changeover from the dominance of the ${A}_{3/2}$ amplitude at the real photon point $({Q}^{2}=0)$ to a ${Q}^{2}$ where ${A}_{1/2}$ begins to dominate. The scalar amplitude ${S}_{1/2}$ drops rapidly with ${Q}^{2}$ consistent with quark model prediction. For the $N(1710){\frac{1}{2}}^{+}$ resonance our analysis shows significant strength for the ${A}_{1/2}$ amplitude at ${Q}^{2}l2.5$ ${\mathrm{GeV}}^{2}$.

Published
2015
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6. 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
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7. Strangeness Suppression ofqq¯Creation Observed in Exclusive Reactions

Author

V. Sytnik, M. Ungaro, R. Paremuzyan, Gerard Gilfoyle, S. Chandavar, K. Livingston, D. Sokhan, B. McKinnon, M. Aghasyan, M. Mirazita, V. Batourine, M. Battaglieri, I. Zonta, M. Garçon, X. Wei, K. Joo, Jie Zhang, C. E. Hyde, E. Golovatch, S. Koirala, P. Peng, C. Munoz Camacho, J. Ball, D. S. Carman, Diane Schott, A. I. Ostrovidov, K. Park, R. A. Schumacher, M. Khandaker, V. Crede, S. Strauch, Victor Mokeev, S. Niccolai, D. G. Ireland, A. Movsisyan, Latifa Elouadrhiri, C. Djalali, H. Jiang, D. P. Watts, Volker D. Burkert, A. S. Biselli, C. A. Meyer, N. K. Walford, A. V. Vlassov, H. Voskanyan, A. Kim, W. I. Levine, J. A. Fleming, G. V. Fedotov, H. Hakobyan, C. Hanretty, T. A. Forest, Sergey Kuleshov, P. L. Cole, E. Voutier, R. A. Montgomery, W. J. Briscoe, C. I. Moody, R. De Vita, P. Lenisa, P. Eugenio, K. P. Adhikari, M. D. Mestayer, D. Protopopescu, N. Dashyan, P. Roy, Andrew Puckett, O. Cortes, F. X. Girod, I. Bedlinskiy, Ye Tian, Martin K. Mayer, K. L. Giovanetti, B. Garillon, J. W. Price, S. Pozdniakov, S. Boiarinov, M. Guidal, R. Dupre, H. Y. Lu, L. Colaneri, A. Simonyan, Larry Weinstein, S. Anefalos Pereira, Brian Raue, M. S. Saini, F. Sabatié, Z. W. Zhao, K. A. Griffioen, D. Doughty, M. Holtrop, A. D'Angelo, H. S. Jo, A. El Alaoui, J. T. Goetz, L. El Fassi, Luciano Pappalardo, M. Hattawy, Y. Ilieva, G. Charles, A. Deur, S. Pisano, Nicholas Zachariou, W. K. Brooks, V. P. Kubarovsky, P. Nadel-Turonski, G. Rosner, D. Rimal, I. Niculescu, O. Pogorelko, S. M. Hughes, Y. Ghandilyan, H. Moutarde, B. Guegan, M. Ripani, Dustin Keller, B. Vernarsky, Michael Wood, Alessandro Rizzo, W. Phelps, W. Tang, M. Osipenko, W. Kim, G. Niculescu, I. J. D. MacGregor, A. Celentano, R. W. Gothe, and M. Contalbrigo

Subjects
Physics, Quark, Particle physics, High energy, Meson production, Proton, 010308 nuclear & particles physics, High Energy Physics::Lattice, High Energy Physics::Phenomenology, Nuclear Theory, General Physics and Astronomy, Strangeness, 01 natural sciences, Hadronization, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics
Abstract

In this study, we measured the ratios of electroproduction cross sections from a proton target for three exclusive meson-baryon final states: ΛK+, pπ0, and nπ+, with the CLAS detector at Jefferson Lab. Using a simple model of quark hadronization, we extract qq¯ creation probabilities for the first time in exclusive two-body production, in which only a single qq¯ pair is created. We observe a sizable suppression of strange quark-antiquark pairs compared to nonstrange pairs, similar to that seen in high-energy production.

Published
2014
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8. Publisher's Note: Exclusiveπ0electroproduction atW>2GeV with CLAS [Phys. Rev. C 90, 025205 (2014)]

Author

George Davey Smith, N. A. Baltzell, D. Doughty, M. Khandaker, A. Simonyan, J. P. Ball, A. D'Angelo, Y. Prok, D. S. Carman, I. Zonta, H. Moutarde, K. L. Giovanetti, Larry Weinstein, X. Wei, H. Y. Lu, E. De Sanctis, V. P. Kubarovsky, M. Contalbrigo, Sergey Kuleshov, L. El Fassi, O. Pogorelko, D. I. Sober, D. Protopopescu, M. Garçon, E. Voutier, A. Movsisyan, N. Dashyan, Y. G. Sharabian, S. Chandavar, Frank Klein, A. V. Vlassov, F. X. Girod, D. G. Ireland, Dustin Keller, K. Livingston, C. Munoz Camacho, R. De Vita, K. P. Adhikari, V. Crede, Andrew Puckett, Lorenzo Zana, Martin K. Mayer, K. Hafidi, R. Dupre, S. Anefalos Pereira, V. Sytnik, M. Battaglieri, P. L. Cole, Z. W. Zhao, H. Hakobyan, H. S. Jo, B. McKinnon, S. Strauch, W. Kim, S. Niccolai, H. Avakian, P. Nadel-Turonski, B. Guegan, R. A. Montgomery, M. Mirazita, I. Niculescu, M. Yurov, E. Phelps, Diane Schott, H. Voskanyan, N. Gevorgyan, S. Fegan, S. Koirala, A. I. Ostrovidov, K. Park, G. V. Fedotov, W. J. Briscoe, E. Pasyuk, P. Roy, C. Djalali, A. Celentano, R. W. Gothe, M. Ripani, Volker D. Burkert, M. Guidal, A. S. Biselli, D. P. Watts, H. Egiyan, Nicholas M. Harrison, A. El Alaoui, L. Colaneri, Gerard Gilfoyle, D. Sokhan, D. G. Jenkins, W. I. Levine, M. Holtrop, Nicholas Zachariou, N. Markov, R. A. Schumacher, S. E. Kuhn, M. Hattawy, S. Pisano, Luciano Pappalardo, O. Cortes, I. Bedlinskiy, J. A. Fleming, J. Bono, K. A. Griffioen, E. L. Isupov, N. K. Walford, Andreas Klein, J. J. Phillips, Ye Tian, S. Park, P. Eugenio, Carlos A. Salgado, S. Boiarinov, P. Rossi, W. Tang, Y. Ghandilyan, Barry Ritchie, B. S. Ishkhanov, M. Osipenko, T. A. Forest, S. Stepanyan, B. Garillon, S. Procureur, P. Stoler, A. Kim, E. Seder, K. Hicks, William Brooks, I. J. D. MacGregor, W. Phelps, G. Gavalian, V. Mokeev, I. Senderovich, Alessandro Rizzo, E. Golovatch, L. Elouadrhiri, A. Deur, J. Zhang, J. W. Price, L. Guo, M. Ungaro, K. Joo, V. Batourine, F. Sabatié, C. I. Moody, P. Lenisa, and Brian Raue

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Meson production
Published
2014
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9. 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
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10. 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
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11. 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

12. 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
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13. 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
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14. Deep exclusive π+ electroproduction off the proton at CLAS

Author

K. Park, M. Guidal, R. W. Gothe, J. M. Laget, M. Garçon, K. P. Adhikari, M. Aghasyan, M. J. Amaryan, M. Anghinolfi, H. Avakian, H. Baghdasaryan, J. Ball, N. A. Baltzell, M. Battaglieri, I. Bedlinsky, R. P. Bennett, A. S. Biselli, C. Bookwalter, S. Boiarinov, W. J. Briscoe, W. K. Brooks, V. D. Burkert, D. S. Carman, A. Celentano, S. Chandavar, G. Charles, M. Contalbrigo, V. Crede, A. D’Angelo, A. Daniel, N. Dashyan, R. De Vita, E. De Sanctis, A. Deur, C. Djalali, G. E. Dodge, D. Doughty, R. Dupre, H. Egiyan, A. El Alaoui, L. El Fassi, P. Eugenio, G. Fedotov, S. Fegan, J. A. Fleming, T. A. Forest, A. Fradi, N. Gevorgyan, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, W. Gohn, E. Golovatch, L. Graham, K. A. Griffioen, B. Guegan, L. Guo, K. Hafidi, H. Hakobyan, C. Hanretty, D. Heddle, K. Hicks, D. Ho, M. Holtrop, Y. Ilieva, D. G. Ireland, B. S. Ishkhanov, D. Jenkins, H. S. Jo, D. Keller, M. Khandaker, P. Khetarpal, A. Kim, W. Kim, F. J. Klein, S. Koirala, A. Kubarovsky, V. Kubarovsky, S. E. Kuhn, S. V. Kuleshov, K. Livingston, H. Y. Lu, I. J. D. MacGregor, Y. Mao, N. Markov, D. Martinez, M. Mayer, B. McKinnon, C. A. Meyer, T. Mineeva, M. Mirazita, V. Mokeev, H. Moutarde, E. Munevar, C. Munoz Camacho, P. Nadel-Turonski, C. S. Nepali, S. Niccolai, G. Niculescu, I. Niculescu, M. Osipenko, A. I. Ostrovidov, L. L. Pappalardo, R. Paremuzyan, S. Park, E. Pasyuk, S. Anefalos Pereira, E. Phelps, S. Pisano, O. Pogorelko, S. Pozdniakov, J. W. Price, S. Procureur, D. Protopopescu, A. J. R. Puckett, B. A. Raue, G. Ricco, D. Rimal, M. Ripani, G. Rosner, P. Rossi, F. Sabatié, M. S. Saini, C. Salgado, D. Schott, R. A. Schumacher, E. Seder, H. Seraydaryan, Y. G. Sharabian, E. S. Smith, G. D. Smith, D. I. Sober, D. Sokhan, S. S. Stepanyan, P. Stoler, I. I. Strakovsky, S. Strauch, M. Taiuti, W. Tang, C. E. Taylor, Ye Tian, S. Tkachenko, A. Trivedi, M. Ungaro, B. Vernarsky, H. Voskanyan, E. Voutier, N. K. Walford, D. P. Watts, L. B. Weinstein, D. P. Weygand, M. H. Wood, N. Zachariou, J. Zhang, Z. W. Zhao, I. Zonta, 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
Particle physics, Nuclear and High Energy Physics, Hadron, Theoretical models, Parton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, SCALING LAWS, 0103 physical sciences, VIRTUAL COMPTON-SCATTERING, PION FORM-FACTOR, CROSS-SECTION, HIGH-ENERGIES, PHOTOPRODUCTION, DEUTERON, MESONS, PHOTODISINTEGRATION, MOMENTUM, 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Scattering, Phenomenology (particle physics)
Abstract

The exclusive electroproduction of $\pi^+$ above the resonance region was studied using the $\rm{CEBAF}$ Large Acceptance Spectrometer ($\rm{CLAS}$) at Jefferson Laboratory by scattering a 6 GeV continuous electron beam off a hydrogen target. The large acceptance and good resolution of $\rm{CLAS}$, together with the high luminosity, allowed us to measure the cross section for the $\gamma^* p \to n \pi^+$ process in 140 ($Q^2$, $x_B$, $t$) bins: $0.16, Comment: 18pages, 21figures,2tables

Published
2013
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15. Hard Two-body Photodisintegration of 3He

Author

G. Niculescu, N. Dashyan, D. Protopopescu, E. Cisbani, S. Pozdniakov, G. Rosner, S. Tkachenko, C. Djalali, Yujie Qiang, C. S. Nepali, X. Yan, Idaykis Rodriguez, F. X. Girod, Yordanka Ilieva, L. Guo, Andrew Puckett, G. Charles, Yingxiao Wang, H. Baghdasaryan, Victor Mokeev, S. Beck, Martin K. Mayer, M. S. Saini, Nikolaos Sparveris, X. Zhan, E. Voutier, J. A. Fleming, Ronald Gilman, E. L. Isupov, J. T. Goetz, E. De Sanctis, Dustin Keller, E. Piasetzky, Diane Schott, R. Shneor, G. Ricco, C. W. de Jager, W. Tang, Franco Garibaldi, M. Aghasyan, A. I. Ostrovidov, K. Park, G. G. Petratos, Bryan J. Moffit, Michael Wood, K. Hafidi, T. Mineeva, N. Harrison, A. Deur, Barry Ritchie, P. L. Cole, M. Osipenko, M. Contalbrigo, N. A. Saylor, J. Bono, P. Nadel-Turonski, S. Boiarinov, D. G. Ireland, M. Anghinolfi, H. Seraydaryan, X. Zheng, D. Doughty, I. Zonta, B. S. Ishkhanov, H. Yao, W. K. Brooks, C. E. Taylor, R. A. Schumacher, R. Dupre, N. Bubis, X. Jiang, A. El Alaoui, D. Martinez, M. Battaglieri, V. Crede, B. Lee, K. Joo, Volker D. Burkert, A. S. Biselli, George Davey Smith, D. Heddle, S. Koirala, Guy Ron, V. P. Kubarovsky, K. A. Griffioen, R. De Vita, A. Kim, E. Golovatch, A. Beck, N. A. Baltzell, O. Pogorelko, M. Ungaro, N. D. Kvaltine, Xin Qian, W. J. Briscoe, J. P. Ball, R. A. Montgomery, S. Chandavar, Y. Mao, Friedrich Klein, K. Chirapatpimol, P. Khetarpal, D. S. Carman, P. Stoler, O. Geagla, Nicholas Zachariou, A. Camsonne, S. Anefalos Pereira, Michael Vineyard, A. J. Sarty, N. K. Walford, P. Eugenio, D. G. Meekins, A. D'Angelo, H. Voskanyan, A. T. Katramatou, R. Michaels, Douglas Higinbotham, M. Taiuti, K. Hicks, C. Dutta, Vincent Sulkosky, S. Stepanyan, E. Schulte, E. Munevar, Bogdan Wojtsekhowski, D. Rimal, E. Seder, A. Fradi, B. Vernarsky, S. Lewis, M. J. Amaryan, B. Guegan, C. E. Hyde, F. Sabatié, L. El Fassi, W. U. Boeglin, G. E. Dodge, S. Procureur, R. Nasseripour, C. Munoz Camacho, H. Y. Lu, S. Fegan, R. A. Lindgren, S. Strauch, H. S. Jo, Ishay Pomerantz, J. J. LeRose, C. A. Meyer, S. Pisano, G. V. Fedotov, H. Moutarde, D. P. Watts, H. Egiyan, C. Bookwalter, F. Cusanno, K. Livingston, K. L. Giovanetti, I. Niculescu, I. J. D. MacGregor, K. P. Adhikari, D. P. Weygand, Larry Weinstein, W. Gohn, R. Paremuzyan, Jie Zhang, A. Celentano, R. W. Gothe, Z. W. Zhao, D. Ho, Emily M. McCullough, R. Subedi, D. Sokhan, M. Khandaker, B. McKinnon, B. L. Berman, J. Glister, M. Mirazita, E. Phelps, N. Gevorgyan, V. Batourine, S. Park, S. Niccolai, P. Rossi, H. Hakobyan, M. Guidal, M. Holtrop, A. Daniel, Luciano Pappalardo, S. S. Stepanyan, Mustafa Canan, Kalyan Allada, I. Bedlinskiy, A. Kubarovsky, Sergey Kuleshov, E. Khrosinkova, B. Sawatzky, M. Ripani, A. Saha, W. Kim, 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
Particle physics, Photon, Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, Few-body systems, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Cross section (physics), ANGLE ELASTIC-SCATTERING, CROSS-SECTION, DEUTERON, 0103 physical sciences, medicine, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Scaling, Physics, 010308 nuclear & particles physics, medicine.anatomical_structure, Deuterium, Photodisintegration, Nucleus
Abstract

We have measured cross sections for the {gamma}+{sup 3}He->p+d reaction at photon energies of 0.4 - 1.4 GeV and a center-of-mass angle of 90 deg. We observe dimensional scaling above 0.7 GeV at this center-of-mass angle. This is the first observation of dimensional scaling in the photodisintegration of a nucleus heavier than the deuteron.

Published
2013
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16. Near-threshold neutral pion electroproduction at high momentum transfers and generalized form factors

Author

S. Tkachenko, L. Guo, E. De Sanctis, N. Harrison, M. Aghasyan, D. I. Sober, I. Zonta, A. Celentano, R. W. Gothe, F. X. Girod, G. Charles, F. Sabatié, R. A. Schumacher, W. Tang, P. Stoler, C. E. Hyde, M. Osipenko, J. T. Goetz, N. D. Kvaltine, K. Hicks, David M. Keller, M. Ungaro, D. Martinez, M. Ripani, M. Contalbrigo, W. Gohn, S. Stepanyan, T. Mineeva, P. Eugenio, C. E. Taylor, Andrew Puckett, E. Munevar, Martin K. Mayer, R. De Vita, E. Seder, H. Y. Lu, Michael Wood, K. Hafidi, W. Kim, E. Golovatch, G. Niculescu, M. Taiuti, M. S. Saini, K. Joo, R. Nasseripour, G. Ricco, P. Khetarpal, S. Niccolai, C. A. Meyer, I. Niculescu, E. L. Isupov, S. Anefalos Pereira, G. Rosner, G. V. Fedotov, S. Lewis, K. A. Griffioen, N. A. Saylor, H. Avakian, Y. Mao, S. Boiarinov, I. I. Strakovsky, K. P. Adhikari, H. Hakobyan, D. P. Weygand, R. Dupre, C. Hanretty, J. W. Price, J. Bono, M. Battaglieri, Michael Dugger, R. G. Fersch, N. K. Walford, A. Deur, Friedrich Klein, J. J. Phillips, P. Nadel-Turonski, H. Voskanyan, B. Vernarsky, Brian Raue, W. K. Brooks, I. J. D. MacGregor, S. Park, H. S. Jo, P. L. Cole, W. J. Briscoe, E. Pasyuk, George Davey Smith, Z. W. Zhao, C. Salgado, B. S. Ishkhanov, J. A. Fleming, D. Ho, I. Bedlinskiy, P. Rossi, A. D'Angelo, L. El Fassi, M. Anghinolfi, H. Seraydaryan, V. Crede, V. P. Kubarovsky, S. Koirala, C. Djalali, O. Pogorelko, Y. G. Sharabian, Victor Mokeev, R. A. Montgomery, S. Procureur, E. Phelps, Diane Schott, A. I. Ostrovidov, K. Park, D. G. Ireland, Volker D. Burkert, A. S. Biselli, A. Fradi, S. Pisano, A. Kim, N. A. Baltzell, M. Khandaker, D. Doughty, M. J. Amaryan, H. Moutarde, K. L. Giovanetti, Larry Weinstein, S. S. Stepanyan, A. Kubarovsky, D. Adikaram, M. Guidal, M. Holtrop, Luciano Pappalardo, Sergey Kuleshov, R. Paremuzyan, Gerard Gilfoyle, D. Sokhan, C. Munoz Camacho, B. McKinnon, M. Mirazita, N. Gevorgyan, V. Batourine, A. El Alaoui, Y. Ilieva, Nicholas Zachariou, D. Rimal, K. Livingston, Jie Zhang, Inna Aznauryan, S. Strauch, H. Egiyan, D. Protopopescu, S. Pozdniakov, M. Garçon, M. Y. Gabrielyan, N. Dashyan, H. Baghdasaryan, B. Guegan, S. Fegan, J. P. Ball, D. S. Carman, E. Voutier, 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), 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), 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, Proton, 010308 nuclear & particles physics, Structure function, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, High momentum, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, Near threshold, Pion, CLAS, 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, SYSTEM
Abstract

We report the measurement of near threshold neutral pion electroproduction cross sections and the extraction of the associated structure functions on the proton in the kinematic range $Q^2$ from 2 to 4.5 GeV$^2$ and $W$ from 1.08 to 1.16 GeV. These measurements allow us to access the dominant pion-nucleon s-wave multipoles $E_{0+}$ and $S_{0+}$ in the near-threshold region. In the light-cone sum-rule framework (LCSR), these multipoles are related to the generalized form factors $G_1^{\pi^0 p}(Q^2)$ and $G_2^{\pi^0 p}(Q^2)$. The data are compared to these generalized form factors and the results for $G_1^{\pi^0 p}(Q^2)$ are found to be in good agreement with the LCSR predictions, but the level of agreement with $G_2^{\pi^0 p}(Q^2)$ is poor., Comment: 17 pages, 18 figures, Journal article (Physical Review C)

Published
2013
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17. Experimental study of theP11(1440)andD13(1520)resonances from the CLAS data onep→e′π+π−p′

Author

M. Contalbrigo, I. Zonta, W. Kim, Friedrich Klein, I. I. Strakovsky, M. Guidal, S. Tkachenko, Brian Raue, P. Khetarpal, L. Guo, A. Deur, M. Holtrop, W. K. Brooks, C. S. Nepali, A. Daniel, A. Kim, N. A. Baltzell, H. Moutarde, Luciano Pappalardo, P. Eugenio, C. E. Taylor, J. Ball, V. P. Kubarovsky, A. Celentano, R. W. Gothe, S. S. Stepanyan, A. El Alaoui, Y. Ilieva, V. Crede, O. Pogorelko, E. Golovatch, P. Stoler, H. Hakobyan, L. C. Smith, Nicholas Zachariou, S. Strauch, C. Hanretty, D. Sokhan, M. Anghinolfi, K. Hicks, B. S. Ishkhanov, S. Koirala, H. Seraydaryan, A. Kubarovsky, D. Rimal, W. Tang, Y. G. Sharabian, S. Procureur, K. L. Giovanetti, Z. W. Zhao, A Fradi, H. Y. Lu, I. Bedlinskiy, Michael Wood, E. Seder, H. S. Jo, K. Hafidi, B. Guegan, D. Ho, M. Ungaro, E. De Sanctis, Martin K. Mayer, M. Ripani, K. A. Griffioen, Latifa Elouadrhiri, M. Aghasyan, G. Charles, D. Martinez, Sergey Kuleshov, H. Avakian, D. I. Sober, R. Paremuzyan, C. A. Meyer, Y. Mao, M. S. Saini, G. V. Fedotov, A. Trivedi, I. J. D. MacGregor, B. McKinnon, S. Park, R. A. Schumacher, N. K. Walford, H. Voskanyan, W. J. Briscoe, N. Markov, M. Khandaker, K. P. Adhikari, S. Pisano, K. Livingston, P. Rossi, E. Pasyuk, L. Graham, M. Mirazita, R. Dupre, David M. Keller, M. Battaglieri, T. Mineeva, V. Batourine, A. I. Ostrovidov, R. De Vita, F. X. Girod, K. Park, D. Doughty, S. Stepanyan, D. G. Ireland, E. Munevar, K. Joo, Avraham Klein, E. L. Isupov, D. Protopopescu, P. L. Cole, S. Pozdniakov, Volker D. Burkert, A. S. Biselli, Ye Tian, F. Sabatié, W. Gohn, S. Anefalos Pereira, J. W. Price, D. Schott, S. Boiarinov, George Davey Smith, Michael Vineyard, A. D'Angelo, P. Nadel-Turonski, C. Salgado, Victor Mokeev, C. Djalali, N. D. Kvaltine, D. S. Carman, E. Voutier, G. Ricco, G. Rosner, S. Fegan, C. Bookwalter, N. Dashyan, and H. Baghdasaryan

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Unitarity, Proton, 010308 nuclear & particles physics, Branching fraction, Hadron, 01 natural sciences, Helicity, Excited state, 0103 physical sciences, 010306 general physics, Ground state, Ansatz
Abstract

The transition helicity amplitudes from the proton ground state to the $$P_{11}(1440)$$ and $$D_{13}(1520)$$ excited states ($$\gamma_{v}pN^*$$ electrocouplings) were determined from the analysis of nine independent one-fold differential $$\pi^{+} \pi^{-} p$$ electroproduction cross sections off a proton target, taken with CLAS at photon virtualities 0.25\enskip {\rm GeV$$^{2}$$} $

Published
2012
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18. Measurement of Exclusiveπ0Electroproduction Structure Functions and their Relationship to Transverse Generalized Parton Distributions

Author

A. Kim, R. A. Schumacher, D. Doughty, D. Heddle, L. Graham, F. X. Girod, V. Mokeev, K. A. Griffioen, Y. Mao, S. Strauch, T. A. Forest, P. Nadel-Turonski, D. P. Watts, H. Egiyan, R. P. Bennett, S. Stepanyan, E. Munevar, M. Ungaro, A. V. Vlassov, I. Zonta, Eugene Pasyuk, A. I. Ostrovidov, K. Park, S. Tkachenko, D. G. Ireland, L. Guo, A. El Alaoui, Y. Ilieva, Volker D. Burkert, C. Munoz Camacho, Andrew Puckett, Martin K. Mayer, Nicholas Zachariou, A. S. Biselli, R. De Vita, W. Gohn, K. Joo, M. Khandaker, M. S. Saini, G. Ricco, C. E. Taylor, B. McKinnon, D. Rimal, W. Tang, E. Seder, I. J. D. MacGregor, M. Osipenko, S. Procureur, G. Charles, S. Anefalos Pereira, M. J. Amaryan, M. Mirazita, N. Markov, V. Crede, Latifa Elouadrhiri, S. Pisano, K. Livingston, N. Gevorgyan, N. A. Saylor, S. E. Kuhn, D. Martinez, B. Guegan, C. A. Meyer, A. Celentano, R. W. Gothe, J. A. Fleming, Friedrich Klein, G. V. Fedotov, H. Moutarde, M. Ripani, S. Fegan, Jie Zhang, Brian Raue, R. Paremuzyan, W. Kim, K. L. Giovanetti, G. Niculescu, F. Sabatié, N. D. Kvaltine, E. De Sanctis, H. Hakobyan, C. Djalali, R. Dupre, Larry Weinstein, M. Contalbrigo, M. Battaglieri, C. Hanretty, M. Aghasyan, A. Deur, K. P. Adhikari, D. I. Sober, M. Taiuti, David M. Keller, D. P. Weygand, W. K. Brooks, H. S. Jo, D. Sokhan, C. Bookwalter, P. Stoler, J. W. Price, Michael Wood, I. Bedlinskiy, K. Hafidi, K. Hicks, D. Protopopescu, S. Pozdniakov, M. Garçon, E. Voutier, S. Koirala, G. Rosner, S. Chandavar, E. Phelps, S. Park, N. Dashyan, P. Rossi, E. L. Isupov, V. P. Kubarovsky, A. Kubarovsky, Ye Tian, George Davey Smith, A. D'Angelo, O. Pogorelko, L. El Fassi, H. Avakian, H. Baghdasaryan, S. Boiarinov, M. Guidal, M. Holtrop, A. Daniel, Luciano Pappalardo, N. K. Walford, H. Voskanyan, W. J. Briscoe, J. P. Ball, Y. Prok, D. S. Carman, S. Niccolai, B. S. Ishkhanov, Sergey Kuleshov, H. Y. Lu, P. Khetarpal, N. A. Baltzell, A. Fradi, I. Niculescu, P. Eugenio, D. Schott, T. Mineeva, C. Salgado, Z. W. Zhao, M. F. Vineyard, M. Anghinolfi, H. Seraydaryan, and Y. G. Sharabian

Subjects
Physics, Particle physics, 010308 nuclear & particles physics, Structure function, General Physics and Astronomy, Sigma, Parton, 01 natural sciences, Helicity, Transverse plane, 0103 physical sciences, Sensitivity (control systems), 010306 general physics, Nucleon, Phenomenology (particle physics)
Abstract

Exclusive $$\pi^0$$ electroproduction at a beam energy of 5.75 GeV has been measured with the Jefferson Lab CLAS spectrometer. Differential cross sections were measured at more than 1800 kinematic values in $Q^2$, $x_B$, $t$, and $$\phi_\pi$$, in the $Q^2$ range from 1.0 to 4.6 GeV$^2$$,\ $$-t$ up to 2 GeV$^2$, and $x_B$ from 0.1 to 0.58. Structure functions $$\sigma_T +\epsilon \sigma_L, \sigma_{TT}$$ and $$\sigma_{LT}$$ were extracted as functions of $t$ for each of 17 combinations of $Q^2$ and $x_B$. The data were compared directly with two handbag-based calculations including both longitudinal and transversity GPDs. Inclusion of only longitudinal GPDs very strongly underestimates $$\sigma_T +\epsilon \sigma_L$$ and fails to account for $$\sigma_{TT}$$ and $$\sigma_{LT}$$, while inclusion of transversity GPDs brings the calculations into substantially better agreement with the data. There is very strong sensitivity to the relative contributions of nucleon helicity flip and helicity non-flip processes. The results confirm that exclusive $$\pi^0$$ electroproduction offers direct experimental access to the transversity GPDs.

Published
2012
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19. Comparison of forward and backwardpppair knockout in3He(e,e′pp)n

Author

V. Crede, S. Strauch, M. Contalbrigo, M. Paolone, H. Egiyan, M. J. Amaryan, S. Niccolai, M. Taiuti, N. Dashyan, D. G. Jenkins, N. A. Saylor, S. Procureur, S. V. Kuleshov, Michael Wood, D. Sokan, B. S. Ishkhanov, K. Hafidi, W. Tang, M. Y. Gabrielyan, K. L. Giovanetti, B. McKinnon, H. S. Jo, K. A. Griffioen, M. Osipenko, Larry Weinstein, A. D'Angelo, A. Celentano, R. W. Gothe, E. Voutier, E. De Sanctis, D. Doughty, P. Khetarpal, G. Charles, S. Pisano, F. X. Girod, H. Baghdasaryan, J. Ball, A. El Alaoui, S. Chandavar, M. Aghasyan, L. El Fassi, V. Mokeev, Lorenzo Zana, M. Mirazita, J. M. Laget, S. Park, H. Moutarde, S. S. Stepanyan, K. Park, V. P. Kubarovsky, W. Gohn, D. Rimal, P. Rossi, D. I. Sober, D. G. Ireland, S. Tkachenko, H. Voskanyan, R. Dupre, N. Gevorgyan, K. Joo, M. Battaglieri, R. A. Schumacher, Volker D. Burkert, A. S. Biselli, Latifa Elouadrhiri, A. Kim, B. Zhao, W. Kim, A. Kubarovsky, G. Rosner, G. V. Fedotov, G. Niculescu, P. L. Cole, W. K. Brooks, R. Paremuzyan, W. J. Briscoe, M. Guidal, S. Pozdniakov, K. P. Adhikari, D. S. Carman, M. Khandaker, S. Stepanyan, E. Munevar, Gerard Gilfoyle, R. De Vita, G. E. Dodge, H. Y. Lu, N. D. Kvaltine, A. Daniel, I. Niculescu, Luciano Pappalardo, I. J. D. MacGregor, D. Schott, K. Hicks, C. E. Hyde, G. Ricco, Brian Raue, B. Guegan, M. Ripani, Chaden Djalali, S. E. Kuhn, Elton Smith, M. Anghinolfi, H. Seraydaryan, and M. S. Saini

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Momentum (technical analysis), Proton, 010308 nuclear & particles physics, Nuclear Theory, Momentum transfer, EMC effect, Few-body systems, 01 natural sciences, Nuclear physics, 0103 physical sciences, Nuclear force, Neutron, Nuclear Experiment, 010306 general physics, Wave function
Abstract

Measuring nucleon-nucleon Short Range Correlations (SRC) has been a goal of the nuclear physics community for many years. They are an important part of the nuclear wavefunction, accounting for almost all of the high-momentum strength. They are closely related to the EMC effect. While their overall probability has been measured, measuring their momentum distributions is more difficult. In order to determine the best configuration for studying SRC momentum distributions, we measured the 3He(e,e'pp)n reaction, looking at events with high momentum protons (pp > 0.35 GeV/c) and a low momentum neutron (pn < 0.2 GeV/c). We examined two angular configurations: either both protons emitted forward or one proton emitted forward and one backward (with respect to the momentum transfer, →q). Thus, the measured relative momentum distribution of the events with one forward and one backward proton was much closer to the calculated initial-state pp relative momentum distribution, indicating that this is the preferred configuration for measuring SRC.

Published
2012
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20. Publisher’s Note: Measurement of the NeutronF2Structure Function via Spectator Tagging with CLAS [Phys. Rev. Lett.108, 142001 (2012)]

Author

C. E. Hyde, D. G. Ireland, V. Crede, D. Protopopescu, S. Pozdniakov, H. C. Fenker, D. Adikaram, M. Guidal, Nicholas Kvaltine, G. Niculescu, P. Stoler, Wolodymyr Melnitchouk, G. V. Fedotov, N. Kalantarians, B. Dey, K. Hicks, A. Celentano, R. W. Gothe, M. J. Amaryan, H. Avakian, M. Holtrop, D. P. Weygand, E. De Sanctis, A. Daniel, A. El Alaoui, E. L. Isupov, M. Aghasyan, Luciano Pappalardo, B. Guegan, D. I. Sober, H. Moutarde, M. Contalbrigo, W. Kim, G. Charles, M. Ripani, S. Fegan, K. L. Giovanetti, C. E. Keppel, S. Bültmann, E. Seder, W. J. Briscoe, E. Pasyuk, Larry Weinstein, D. Rimal, Alexei V. Klimenko, D. Doughty, P. Khetarpal, P. E. Bosted, Carlos A. Salgado, Andreas Klein, K. Livingston, M. Ispiryan, Michael Vineyard, D. Heddle, K. P. Adhikari, S. Park, Brian Raue, N. Baillie, Y. Prok, D. S. Carman, B. Zhao, Lorenzo Zana, N. Guler, P. Rossi, H. S. Jo, B. McKinnon, W. Tang, S. E. Kuhn, P. Eugenio, M. Taiuti, R. De Vita, E. Voutier, M. Osipenko, N. Dashyan, D. Branford, V. P. Kubarovsky, M. Khandaker, F. Sabatié, S. S. Jawalkar, S. Niccolai, M. Gabrielyan, N. Gevorgyan, Frank Klein, I. J. D. MacGregor, Sergey Kuleshov, Yordanka Ilieva, M. Anghinolfi, S. Tkachenko, Y. G. Sharabian, S. Anefalos Pereira, Michael Wood, E. V. Hungerford, K. Hafidi, Gerard Gilfoyle, G. Ricco, F. X. Girod, D. Sokhan, M. S. Saini, T. Mineeva, M. E. Christy, Diane Schott, A. I. Ostrovidov, K. Park, Hovhannes Baghdasaryan, S. Strauch, Volker D. Burkert, A. S. Biselli, J. Domingo, A. Fradi, S. Pisano, B. Morrison, C. Djalali, K. A. Griffioen, Dipangkar Dutta, L. Guo, M. Ungaro, J. Arrington, R. A. Schumacher, L. Graham, S. S. Stepanyan, R. Dupre, M. Battaglieri, S. Stepanyan, William Brooks, Rolf Ent, G. E. Dodge, H. Y. Lu, S. Procureur, I. Niculescu, A. Kim, J. Zhang, G. Rosner, Y. Mao, S. Chandavar, J. W. Price, A. Ni, V. Tvaskis, D. P. Watts, H. Egiyan, P. Nadel-Turonski, N. Markov, E. Munevar, P. M. King, E. Golovatch, W. Gohn, L. Elouadrhiri, A. Deur, P. L. Cole, A. D'Angelo, and L. El Fassi

Subjects
Physics, Nuclear physics, Structure function, General Physics and Astronomy, Neutron
Published
2012
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21. Measurement of the Neutron F-2 Structure Function via Spectator Tagging with CLAS

Author

R. Dupre, M. Battaglieri, S. S. Stepanyan, W. Kim, G. Niculescu, B. Zhao, H. Avakian, F. Sabatié, H. C. Fenker, A. I. Ostrovidov, C. E. Hyde, Y. Prok, D. S. Carman, K. Park, D. G. Ireland, Latifa Elouadrhiri, T. Mineeva, M. E. Christy, Volker D. Burkert, A. S. Biselli, S. Tkachenko, S. E. Kuhn, G. V. Fedotov, S. S. Jawalkar, E. Voutier, C. E. Keppel, K. A. Griffioen, D. P. Watts, N. D. Kvaltine, I. J. D. MacGregor, W. J. Briscoe, G. E. Dodge, H. Y. Lu, A. Kim, E. Munevar, Y. Mao, Lorenzo Zana, K. P. Adhikari, D. P. Weygand, M. Khandaker, F. X. Girod, M. Contalbrigo, E. V. Hungerford, R. Ent, Dipangkar Dutta, Sergey Kuleshov, B. Guegan, S. Fegan, Alexei V. Klimenko, Hovanes Egiyan, D. Heddle, W. Tang, H. S. Jo, E. De Sanctis, A. El Alaoui, I. Niculescu, P. Bosted, N. Baillie, M. J. Amaryan, B. A. Raue, J. Domingo, A. Fradi, M. Aghasyan, D. Adikaram, John Arrington, M. Osipenko, M. Guidal, D. I. Sober, P. Khetarpal, M. S. Saini, D. Schott, W. Gohn, R. A. Schumacher, J. W. Price, C. Salgado, G. Charles, N. Dashyan, Wally Melnitchouk, M. Y. Gabrielyan, V. Crede, M. Holtrop, N. Markov, H. Moutarde, S. Pisano, Gerard Gilfoyle, A. Daniel, G. Ricco, G. Rosner, M. Ispiryan, D. Rimal, L. Graham, Michael Wood, K. Hafidi, K. L. Giovanetti, Larry Weinstein, C. Djalali, Luciano Pappalardo, S. Strauch, V. Tvaskis, H. Baghdasaryan, P. Eugenio, D. Doughty, D. Sokhan, R. De Vita, Friedrich Klein, L. Guo, M. Ungaro, M. Taiuti, Eugene Pasyuk, S. Bültmann, S. Chandavar, Andrea Celentano, S. Procureur, A. Deur, N. Kalantarians, R. W. Gothe, K. Livingston, B. McKinnon, S. Anefalos Pereira, E. Seder, M. Anghinolfi, N. Guler, Michael Vineyard, P. Stoler, Y. Ilieva, Jie Zhang, S. Stepanyan, D. Branford, B. Dey, P. M. King, Y. G. Sharabian, K. Hicks, E. Golovatch, Avraham Klein, N. Gevorgyan, E. L. Isupov, S. Niccolai, A. Ni, V. P. Kubarovsky, A. D'Angelo, S. Park, P. Rossi, P. Nadel-Turonski, L. El Fassi, William Brooks, M. Ripani, B. Morrison, P. L. Cole, D. Protopopescu, S. Pozdniakov, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), 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
Proton, Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], NUCLEAR-STRUCTURE, PROTON, 01 natural sciences, Neutron time-of-flight scattering, High Energy Physics - Experiment, Settore FIS/04 - Fisica Nucleare e Subnucleare, Nuclear physics, High Energy Physics - Experiment (hep-ex), DUALITY, 0103 physical sciences, PION, Neutron cross section, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Neutron, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Scattering, Momentum transfer, INELASTIC ELECTRON-SCATTERING, STRUCTURE-FUNCTION RATIO, DEUTERON, MODEL, FORM, Deuterium, Nucleon
Abstract

We report on the first measurement of the F2 structure function of the neutron from semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to < 100 MeV and their angles to < 100 degrees relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The F2n data collected cover the nucleon resonance and deep-inelastic regions over a wide range of Bjorken x for 0.65 < Q2 < 4.52 GeV2, with uncertainties from nuclear corrections estimated to be less than a few percent. These measurements provide the first determination of the neutron to proton structure function ratio F2n/F2p at 0.2 < x < 0.8 with little uncertainty due to nuclear effects., 6 pages, 3 pages

Published
2012
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22. Electromagnetic decay of theΣ0(1385)toΛγ

Author

P. Nadel-Turonski, L. Casey, R. Dupre, R. Dickson, M. Battaglieri, J. P. Ball, D. S. Carman, E. De Sanctis, Y. G. Sharabian, V. Kuznetsov, M. Aghasyan, D. I. Sober, P. Eugenio, R. De Vita, A. M. Micherdzinska, S. Anefalos Pereira, G. Gavalian, M. Taiuti, E. Voutier, E. L. Isupov, D. Keller, H. Y. Lu, M. Ripani, S. Niccolai, M. Amarian, Kei Moriya, C. A. Meyer, G. V. Fedotov, M. Khandaker, B. Guegan, S. Fegan, I. Niculescu, D. Protopopescu, H. Hakobyan, Z. W. Zhao, George Davey Smith, K. P. Adhikari, D. G. Jenkins, S. Pozdniakov, A. D'Angelo, D. Doughty, M. S. Saini, D. Schott, R. P. Bennett, B. Morrison, R. A. Schumacher, R. Paremuzyan, L. El Fassi, S. Strauch, Michael Vineyard, Barry Ritchie, L. Graham, F. X. Girod, F. Sabatié, N. Dashyan, P. Konczykowski, D. P. Watts, C. Djalali, S. Procureur, I. Bedlinskiy, Elton Smith, N. Markov, Lorenzo Zana, P. L. Cole, A. Ni, A. El Alaoui, Y. Ilieva, S. Pisano, Sergey Kuleshov, T. A. Forest, Friedrich Klein, H. Seraydaryan, H. S. Jo, Brian Raue, A. Kim, Avraham Klein, Nicholas Zachariou, C. Salgado, H. Baghdasaryan, S. L. Careccia, M. Y. Gabrielyan, E. Seder, J. W. Price, S. Park, P. Khetarpal, K. L. Giovanetti, B. McKinnon, P. Rossi, Larry Weinstein, D. Adikaram, M. Guidal, D. Branford, V. Crede, M. Mirazita, M. Holtrop, B. Moreno, A. Daniel, N. Gevorgyan, C. Hanretty, G. Rosner, V. Batourine, Luciano Pappalardo, A. I. Ostrovidov, K. Park, D. G. Ireland, S. S. Stepanyan, Volker D. Burkert, A. S. Biselli, Victor Mokeev, Hovanes Egiyan, H. Moutarde, B. Vernarsky, K. Joo, E. Munevar, I. I. Strakovsky, A. Deur, W. K. Brooks, C. E. Taylor, E. Golovatch, W. Gohn, W. Kim, G. Niculescu, W. Tang, M. Osipenko, B. Zhao, S. S. Jawalkar, I. J. D. MacGregor, M. Contalbrigo, V. P. Kubarovsky, O. Pogorelko, R. W. Gothe, J. McAndrew, Michael Wood, K. Hafidi, W. J. Briscoe, E. Pasyuk, P. Stoler, B. Dey, and K. Hicks

Subjects
Physics, Nuclear and High Energy Physics, Meson, 010308 nuclear & particles physics, Hadron, Elementary particle, Lambda, Lambda baryon, 01 natural sciences, Sigma baryon, Nuclear physics, Particle decay, 0103 physical sciences, High Energy Physics::Experiment, Atomic physics, 010306 general physics, Nucleon
Abstract

The electromagnetic decay $\Sigma^0(1385) \to \Lambda \gamma$ was studied using the CLAS detector at the Thomas Jefferson National Accelerator Facility. A real photon beam with a maximum energy of 3.8 GeV was incident on a proton target, producing an exclusive final state of $K^+\Sigma^{*0}$. We report the decay widths ratio $\Sigma^0(1385) \to \Lambda\gamma$/ $\Sigma^0(1385) \to \Lambda\pi^0$ = $1.42 \pm 0.12(\text{stat})_{-0.07}^{+0.11}(\text{sys})$%. This ratio is larger than most theoretical predictions by factors ranging from 1.5-3, but is consistent with the only other experimental measurement. From the reported ratio we calculate the partial width and electromagnetic transition magnetic moment for $\Sigma^0(1385) \to \Lambda\gamma$.

Published
2011
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23. Coherent photoproduction ofπ+fromHe3

Author

C. E. Hyde, H. Moutarde, K. L. Giovanetti, Larry Weinstein, William Brooks, P. Khetarpal, B. McKinnon, C. Djalali, E. S. Smith, B. Guegan, G. Rosner, K. A. Griffioen, S. Fegan, Barry Ritchie, W. J. Briscoe, E. Pasyuk, B. L. Berman, S. Park, R. W. Gothe, Y. Perrin, H. Y. Lu, D. Branford, Frank Klein, W. Gohn, Sergey Kuleshov, M. Mirazita, F. X. Girod, Dustin Keller, N. Dashyan, J. McAndrew, P. L. Cole, Z. W. Zhao, George Davey Smith, I. Niculescu, P. Collins, D. G. Ireland, V. Crede, K. Hafidi, A. Deur, Yordanka Ilieva, W. Tang, M. Taiuti, S. Strauch, C. E. Taylor, A. D'Angelo, R. A. Schumacher, M. Osipenko, B. Morrison, D. P. Weygand, L. Casey, V. Batourine, L. Graham, D. Adikaram, L. El Fassi, P. Stoler, G. Niculescu, I. J. D. MacGregor, V. P. Kubarovsky, A. M. Micherdzinska, F. Sabatié, B. Zhao, M. Holtrop, J. P. Ball, R. Dupre, M. Battaglieri, B. Dey, S. Stepanyan, A. Daniel, D. S. Carman, C. Hanretty, Diane Schott, E. Voutier, R. Suleiman, A. Kim, D. J. Tedeschi, A. I. Ostrovidov, I. Bedlinskiy, P. Konczykowski, Andreas Klein, S. Procureur, D. P. Watts, V. Kuznetsov, H. Egiyan, K. Park, E. Munevar, Pawel Nadel-Turonski, S. Niccolai, Rakhsha Nasseripour, M. H. Wood, R. Paremuzyan, A. Ni, Gerard Gilfoyle, Volker D. Burkert, A. S. Biselli, D. Sokhan, A. El Alaoui, B. Vernarsky, B. Moreno, K. Livingston, R. Dickson, A. Fradi, S. Pisano, D. Protopopescu, S. Pozdniakov, Nicholas Kvaltine, D. Doughty, D. Heddle, M. Khandaker, M. Gabrielyan, M. Anghinolfi, H. Seraydaryan, S. Tkachenko, Y. G. Sharabian, M. Ripani, Carlos A. Salgado, Paolo Rossi, Martin K. Mayer, Michael Paolone, M. S. Saini, J. T. Goetz, S. E. Kuhn, E. De Sanctis, D. I. Sober, R. De Vita, S. Anefalos Pereira, M. Ungaro, S. S. Stepanyan, J. W. Price, K. P. Adhikari, H. Hakobyan, K. Moriya, E. L. Isupov, Michael Vineyard, and W. Kim

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, 0103 physical sciences, 010306 general physics, 01 natural sciences
Published
2011
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24. All the menisco-ligamentary structures of the medial plane play a significant role in controlling anterior tibial translation and tibial rotation of the knee. Cadaveric study of 29 knees with the Dyneelax® laximeter.

Author

Guegan B, Drouineau M, Common H, and Robert H

Abstract

Purpose: This study aimed to determine the respective roles of the anterior cruciate ligament (ACL) and the different components of the medial plane in the control of anterior tibial translation and internal and external tibial rotation., Methods: Twenty-nine fresh lower limbs, disarticulated at the hip, were tested in the anatomy laboratory. The following structures were isolated: the ACL, the anteromedial retinaculum (AMR), the medial collateral ligament (superficial and deep MCL), the posterior medial capsule (PMC) and the posterior horn of the medial meniscus (PHMM). The lower limb was positioned at 30° of flexion on the Dyneelax® laximeter (0.1 mm and 0.1° accuracies) and underwent anterior loads up to 200 N and internal and external tibial rotations sectioned from front to back. and the knee was then retested. The results were presented as relative gains in translation and rotations for each structure. Student's t test and Wilcoxon tests were used., Results: The relative gains in translation for the ACL, AMR, superficial MCL, deep MCL, PMC and PHMM, respectively, were 42.9%, 6.7%, 7.4%, 6%, 7.5% and 11.6%. The relative gains in internal rotation for ACL, AMR, superficial MCL, deep MCL, PMC and PHMM, respectively, were 13%, 6.9%, 4.6%, 3.9%, 13% and 8%. The relative gains in external rotation for ACL, AMR, superficial MCL, deep MCL, PMC and medial meniscus, respectively, were 8.9%, 6%, 9.7%, 13.8%,11.2% and 8.5%. All the relative gains in translation, internal and external rotations were significant at each step of transection ( p  < 0.01)., Conclusions: The ligamentous structures of the medial plane constitute a functional unit in which each component has a specific passive contribution. This study highlights the importance of recognising the extent of the medial ligament tears and performing a medial side anatomic and individual reconstruction and a suture of a ramp lesion, in addition to an ACL surgery., Competing Interests: The authors declare no conflict of interest., (© 2024 The Author(s). Journal of Experimental Orthopaedics published by John Wiley & Sons Ltd on behalf of European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

Published
2024
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26. Impact of high-intensity interval training with or without l-citrulline on physical performance, skeletal muscle, and adipose tissue in obese older adults.

Author

Marcangeli V, Youssef L, Dulac M, Carvalho LP, Hajj-Boutros G, Reynaud O, Guegan B, Buckinx F, Gaudreau P, Morais JA, Mauriège P, Noirez P, Aubertin-Leheudre M, and Gouspillou G

Subjects
Adipose Tissue, Aged, Citrulline, Female, Hand Strength, Humans, Male, Muscle, Skeletal metabolism, Obesity therapy, Physical Functional Performance, Polyesters metabolism, Quality of Life, High-Intensity Interval Training methods
Abstract

Background: Aging is associated with a progressive decline in skeletal muscle mass and strength as well as an increase in adiposity. These changes may have devastating impact on the quality of life of older adults. Mitochondrial dysfunctions have been implicated in aging-related and obesity-related deterioration of muscle function. Impairments in mitochondrial quality control processes (biogenesis, fusion, fission, and mitophagy) may underlie this accumulation of mitochondrial dysfunction. High-intensity interval training (HIIT) was shown to improve muscle and mitochondrial function in healthy young and old adults and to improve body composition in obese older adults. Recent studies also positioned citrulline (CIT) supplementation as a promising intervention to counter obesity-related and aging-related muscle dysfunction. In the present study, our objectives were to assess whether HIIT, alone or with CIT, improves muscle function, functional capacities, adipose tissue gene expression, and mitochondrial quality control processes in obese older adults., Methods: Eighty-one-old and obese participants underwent a 12 week HIIT with or without CIT on an elliptical trainer [HIIT-CIT: 20 men/25 women, 67.2 ± 5.0 years; HIIT-placebo (PLA): 18 men/18 women, 68.1 ± 4.1 years]. Handgrip and quadriceps strength, lower limb muscle power, body composition, waist circumference, and functional capacities were assessed pre and post intervention. Vastus lateralis muscle biopsies were performed in a subset of participants to quantify markers of mitochondrial content (TOM20 and OXPHOS subunits), biogenesis (TFAM), fusion (MFN1&2, OPA1), fission (DRP1), and mitophagy (Parkin). Subcutaneous abdominal adipose tissue biopsies were also performed to assess the expression of genes involved in lipid metabolism., Results: HIIT-PLA and HIIT-CIT displayed improvements in functional capacities (P < 0.05), total (mean ± SD: HIIT-PLA: +1.27 ± 3.19%, HIIT-CIT: +1.05 ± 2.91%, P < 0.05) and leg lean mass (HIIT-PLA: +1.62 ± 3.85%, HIIT-CIT: +1.28 ± 4.82%, P < 0.05), waist circumference (HIIT-PLA: -2.2 ± 2.9 cm, HIIT-CIT: -2.6 ± 2.5 cm, P < 0.05), and muscle power (HIIT-PLA: +15.81 ± 18.02%, HIIT-CIT: +14.62 ± 20.02%, P < 0.05). Only HIIT-CIT decreased fat mass (-1.04 ± 2.42%, P < 0.05) and increased handgrip and quadriceps strength (+4.28 ± 9.36% and +10.32 ± 14.38%, respectively, P < 0.05). Both groups increased markers of muscle mitochondrial content, mitochondrial fusion, and mitophagy (P < 0.05). Only HIIT-CIT decreased the expression of the lipid droplet-associated protein CIDEA (P < 0.001)., Conclusions: High-intensity interval training is effective in improving functional capacities, lean mass, muscle power, and waist circumference in obese older adults. HIIT also increases markers of mitochondrial biogenesis, mitochondrial fusion, and mitophagy. Importantly, adding CIT to HIIT results in a greater increase in muscle strength and a significant decrease in fat mass. The present study therefore positions HIIT combined with CIT as an effective intervention to improve the health status of obese older adults., (© 2022 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of Society on Sarcopenia, Cachexia and Wasting Disorders.)

Published
2022
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27. Cross Sections for the Exclusive Photon Electroproduction on the Proton and Generalized Parton Distributions.

Author

Jo HS, Girod FX, Avakian H, Burkert VD, Garçon M, Guidal M, Kubarovsky V, Niccolai S, Stoler P, Adhikari KP, Adikaram D, Amaryan MJ, Anderson MD, Anefalos Pereira S, Ball J, Baltzell NA, Battaglieri M, Batourine V, Bedlinskiy I, Biselli AS, Boiarinov S, Briscoe WJ, Brooks WK, Carman DS, Celentano A, Chandavar S, Charles G, Colaneri L, Cole PL, Compton N, Contalbrigo M, Crede V, D'Angelo A, Dashyan N, De Vita R, De Sanctis E, Deur A, Djalali C, Dupre R, Alaoui AE, Fassi LE, Elouadrhiri L, Fedotov G, Fegan S, Filippi A, Fleming JA, Garillon B, Gevorgyan N, Ghandilyan Y, Gilfoyle GP, Giovanetti KL, Goetz JT, Golovatch E, Gothe RW, Griffioen KA, Guegan B, Guler N, Guo L, Hafidi K, Hakobyan H, Harrison N, Hattawy M, Hicks K, Hirlinger Saylor N, Ho D, Holtrop M, Hughes SM, Ilieva Y, Ireland DG, Ishkhanov BS, Jenkins D, Joo K, Joosten S, Keller D, Khachatryan G, Khandaker M, Kim A, Kim W, Klein A, Klein FJ, Kuhn SE, Kuleshov SV, Lenisa P, Livingston K, Lu HY, MacGregor IJ, McKinnon B, Meziani ZE, Mirazita M, Mokeev V, Montgomery RA, Moutarde H, Movsisyan A, Munevar E, Munoz Camacho C, Nadel-Turonski P, Net LA, Niculescu G, Osipenko M, Ostrovidov AI, Paolone M, Park K, Pasyuk E, Phillips JJ, Pisano S, Pogorelko O, Price JW, Procureur S, Prok Y, Puckett AJ, Raue BA, Ripani M, Rizzo A, Rosner G, Rossi P, Roy P, Sabatié F, Salgado C, Schott D, Schumacher RA, Seder E, Simonyan A, Skorodumina Iu, Smith GD, Sokhan D, Sparveris N, Stepanyan S, Strakovsky II, Strauch S, Sytnik V, Tian Y, Tkachenko S, Ungaro M, Voskanyan H, Voutier E, Walford NK, Watts DP, Wei X, Weinstein LB, Wood MH, Zachariou N, Zana L, Zhang J, Zhao ZW, and Zonta I

Abstract

Unpolarized and beam-polarized fourfold cross sections (d^{4}σ/dQ^{2}dx&#95;{B}dtdϕ) for the ep→e^{'}p^{'}γ 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&#95;{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 support the model predictions of a larger nucleon size at lower quark-momentum fraction x&#95;{B}.

Published
2015
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28. Towards a resolution of the proton form factor problem: new electron and positron scattering data.

Author

Adikaram D, Rimal D, Weinstein LB, Raue B, Khetarpal P, Bennett RP, Arrington J, Brooks WK, Adhikari KP, Afanasev AV, Amaryan MJ, Anderson MD, Anefalos Pereira S, Avakian H, Ball J, Battaglieri M, Bedlinskiy I, Biselli AS, Bono J, Boiarinov S, Briscoe WJ, Burkert VD, Carman DS, Careccia S, Celentano A, Chandavar S, Charles G, Colaneri L, Cole PL, Contalbrigo M, Crede V, D'Angelo A, Dashyan N, De Vita R, De Sanctis E, Deur A, Djalali C, Dodge GE, Dupre R, Egiyan H, El Alaoui A, El Fassi L, Elouadrhiri L, Eugenio P, Fedotov G, Fegan S, Filippi A, Fleming JA, Fradi A, Garillon B, Gilfoyle GP, Giovanetti KL, Girod FX, Goetz JT, Gohn W, Golovatch E, Gothe RW, Griffioen KA, Guegan B, Guidal M, Guo L, Hafidi K, Hakobyan H, Hanretty C, Harrison N, Hattawy M, Hicks K, Holtrop M, Hughes SM, Hyde CE, Ilieva Y, Ireland DG, Ishkhanov BS, Jenkins D, Jiang H, Jo HS, Joo K, Joosten S, Kalantarians N, Keller D, Khandaker M, Kim A, Kim W, Klein A, Klein FJ, Koirala S, Kubarovsky V, Kuhn SE, Livingston K, Lu HY, MacGregor IJ, Markov N, Mattione P, Mayer M, McKinnon B, Mestayer MD, Meyer CA, Mirazita M, Mokeev V, Montgomery RA, Moody CI, Moutarde H, Movsisyan A, Camacho CM, Nadel-Turonski P, Niccolai S, Niculescu G, Osipenko M, Ostrovidov AI, Park K, Pasyuk E, Peña C, Pisano S, Pogorelko O, Price JW, Procureur S, Prok Y, Protopopescu D, Puckett AJ, Ripani M, Rizzo A, Rosner G, Rossi P, Roy P, Sabatié F, Salgado C, Schott D, Schumacher RA, Seder E, Sharabian YG, Simonyan A, Skorodumina I, Smith ES, Smith GD, Sober DI, Sokhan D, Sparveris N, Stepanyan S, Stoler P, Strauch S, Sytnik V, Taiuti M, Tian Y, Trivedi A, Ungaro M, Voskanyan H, Voutier E, Walford NK, Watts DP, Wei X, Wood MH, Zachariou N, Zana L, Zhang J, Zhao ZW, and Zonta I

Abstract

There is a significant discrepancy between the values of the proton electric form factor, G(E)(p), extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can significantly affect the extraction of G(E)(p) from the unpolarized electron-proton cross sections. We determined the TPE contribution by measuring the ratio of positron-proton to electron-proton elastic scattering cross sections using a simultaneous, tertiary electron-positron beam incident on a liquid hydrogen target and detecting the scattered particles in the Jefferson Lab CLAS detector. This novel technique allowed us to cover a wide range in virtual photon polarization (ϵ) and momentum transfer (Q(2)) simultaneously, as well as to cancel luminosity-related systematic errors. The cross section ratio increases with decreasing ϵ at Q(2)=1.45  GeV(2). This measurement is consistent with the size of the form factor discrepancy at Q(2)≈1.75  GeV(2) and with hadronic calculations including nucleon and Δ intermediate states, which have been shown to resolve the discrepancy up to 2-3  GeV(2).

Published
2015
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29. Longitudinal target-spin asymmetries for deeply virtual compton scattering.

Author

Seder E, Biselli A, Pisano S, Niccolai S, Smith GD, Joo K, Adhikari K, Amaryan MJ, Anderson MD, Anefalos Pereira S, Avakian H, Battaglieri M, Bedlinskiy I, Bono J, Boiarinov S, Bosted P, Briscoe W, Brock J, Brooks WK, Bültmann S, Burkert VD, Carman DS, Carlin C, Celentano A, Chandavar S, Charles G, Colaneri L, Cole PL, Contalbrigo M, Crabb D, Crede V, D'Angelo A, Dashyan N, De Vita R, De Sanctis E, Deur A, Djalali C, Doughty D, Dupre R, El Fassi L, Elouadrhiri L, Eugenio P, Fedotov G, Fegan S, Filippi A, Fleming JA, Fradi A, Garillon B, Garçon M, Gevorgyan N, Ghandilyan Y, Giovanetti KL, Girod FX, Goetz JT, Gohn W, Gothe RW, Griffioen KA, Guegan B, Guidal M, Guo L, Hafidi K, Hakobyan H, Hanretty C, Harrison N, Hattawy M, Hirlinger Saylor N, Holtrop M, Hughes SM, Ilieva Y, Ireland DG, Ishkhanov BS, Isupov EL, Jo HS, Joosten S, Keith CD, Keller D, Khachatryan G, Khandaker M, Kim A, Kim W, Klein A, Klein FJ, Koirala S, Kubarovsky V, Kuhn SE, Lenisa P, Livingston K, Lu HY, MacGregor IJ, Markov N, Mayer M, McKinnon B, Meekins DG, Mineeva T, Mirazita M, Mokeev V, Montgomery R, Moody CI, Moutarde H, Movsisyan A, Munoz Camacho C, Nadel-Turonski P, Niculescu I, Osipenko M, Ostrovidov AI, Paolone M, Pappalardo LL, Park K, Park S, Pasyuk E, Peng P, Phelps W, Pogorelko O, Price JW, Prok Y, Protopopescu D, Puckett AJ, Ripani M, Rizzo A, Rosner G, Rossi P, Roy P, Sabatié F, Salgado C, Schott D, Schumacher RA, Senderovich I, Simonyan A, Skorodumina I, Sokhan D, Sparveris N, Stepanyan S, Stoler P, Strakovsky II, Strauch S, Sytnik V, Taiuti M, Tang W, Tian Y, Ungaro M, Voskanyan H, Voutier E, Walford NK, Watts DP, Wei X, Weinstein LB, Wood MH, Zachariou N, Zana L, Zhang J, and Zonta I

Abstract

A measurement of the electroproduction of photons off protons in the deeply inelastic regime was performed at Jefferson Lab using a nearly 6 GeV electron beam, a longitudinally polarized proton target, and the CEBAF Large Acceptance Spectrometer. Target-spin asymmetries for ep→e^{'}p^{'}γ events, which arise from the interference of the deeply virtual Compton scattering and the Bethe-Heitler processes, were extracted over the widest kinematics in Q^{2}, x&#95;{B}, t, and ϕ, for 166 four-dimensional bins. In the framework of generalized parton distributions, at leading twist the t dependence of these asymmetries provides insight into the spatial distribution of the axial charge of the proton, which appears to be concentrated in its center. These results also bring important and necessary constraints for the existing parametrizations of chiral-even generalized parton distributions.

Published
2015
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30. Strangeness suppression of qq creation observed in exclusive reactions.

Author

Mestayer MD, Park K, Adhikari KP, Aghasyan M, Pereira SA, Ball J, Battaglieri M, Batourine V, Bedlinskiy I, Biselli AS, Boiarinov S, Briscoe WJ, Brooks WK, Burkert VD, Carman DS, Celentano A, Chandavar S, Charles G, Colaneri L, Cole PL, Contalbrigo M, Cortes O, Crede V, D'Angelo A, Dashyan N, De Vita R, Deur A, Djalali C, Doughty D, Dupre R, El Alaoui A, El Fassi L, Elouadrhiri L, Eugenio P, Fedotov G, Fleming JA, Forest TA, Garillon B, Garçon M, Ghandilyan Y, Gilfoyle GP, Giovanetti KL, Girod FX, Goetz JT, Golovatch E, Gothe RW, Griffioen KA, Guegan B, Guidal M, Hakobyan H, Hanretty C, Hattawy M, Holtrop M, Hughes SM, Hyde CE, Ilieva Y, Ireland DG, Jiang H, Jo HS, Joo K, Keller D, Khandaker M, Kim A, Kim W, Koirala S, Kubarovsky V, Kuleshov SV, Lenisa P, Levine WI, Livingston K, Lu HY, MacGregor IJ, Mayer M, McKinnon B, Meyer CA, Mirazita M, Mokeev V, Montgomery RA, Moody CI, Moutarde H, Movsisyan A, Camacho CM, Nadel-Turonski P, Niccolai S, Niculescu G, Niculescu I, Osipenko M, Ostrovidov AI, Pappalardo LL, Paremuzyan R, Peng P, Phelps W, Pisano S, Pogorelko O, Pozdniakov S, Price JW, Protopopescu D, Puckett AJ, Raue BA, Rimal D, Ripani M, Rizzo A, Rosner G, Roy P, Sabatié F, Saini MS, Schott D, Schumacher RA, Simonyan A, Sokhan D, Strauch S, Sytnik V, Tang W, Tian Y, Ungaro M, Vernarsky B, Vlassov AV, Voskanyan H, Voutier E, Walford NK, Watts DP, Wei X, Weinstein LB, Wood MH, Zachariou N, Zhang J, Zhao ZW, and Zonta I

Abstract

We measured the ratios of electroproduction cross sections from a proton target for three exclusive meson-baryon final states: ΛK(+), pπ(0), and nπ(+), with the CLAS detector at Jefferson Lab. Using a simple model of quark hadronization, we extract qq creation probabilities for the first time in exclusive two-body production, in which only a single qq pair is created. We observe a sizable suppression of strange quark-antiquark pairs compared to nonstrange pairs, similar to that seen in high-energy production.

Published
2014
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31. Hard two-body photodisintegration of 3He.

Author

Pomerantz I, Ilieva Y, Gilman R, Higinbotham DW, Piasetzky E, Strauch S, Adhikari KP, Aghasyan M, Allada K, Amaryan MJ, Anefalos Pereira S, Anghinolfi M, Baghdasaryan H, Ball J, Baltzell NA, Battaglieri M, Batourine V, Beck A, Beck S, Bedlinskiy I, Berman BL, Biselli AS, Boeglin W, Bono J, Bookwalter C, Boiarinov S, Briscoe WJ, Brooks WK, Bubis N, Burkert V, Camsonne A, Canan M, Carman DS, Celentano A, Chandavar S, Charles G, Chirapatpimol K, Cisbani E, Cole PL, Contalbrigo M, Crede V, Cusanno F, D'Angelo A, Daniel A, Dashyan N, de Jager CW, De Vita R, De Sanctis E, Deur A, Djalali C, Dodge GE, Doughty D, Dupre R, Dutta C, Egiyan H, El Alaoui A, El Fassi L, Eugenio P, Fedotov G, Fegan S, Fleming JA, Fradi A, Garibaldi F, Geagla O, Gevorgyan N, Giovanetti KL, Girod FX, Glister J, Goetz JT, Gohn W, Golovatch E, Gothe RW, Griffioen KA, Guegan B, Guidal M, Guo L, Hafidi K, Hakobyan H, Harrison N, Heddle D, Hicks K, Ho D, Holtrop M, Hyde CE, Ireland DG, Ishkhanov BS, Isupov EL, Jiang X, Jo HS, Joo K, Katramatou AT, Keller D, Khandaker M, Khetarpal P, Khrosinkova E, Kim A, Kim W, Klein FJ, Koirala S, Kubarovsky A, Kubarovsky V, Kuleshov SV, Kvaltine ND, Lee B, LeRose JJ, Lewis S, Lindgren R, Livingston K, Lu HY, MacGregor IJ, Mao Y, Martinez D, Mayer M, McCullough E, McKinnon B, Meekins D, Meyer CA, Michaels R, Mineeva T, Mirazita M, Moffit B, Mokeev V, Montgomery RA, Moutarde H, Munevar E, Munoz Camacho C, Nadel-Turonski P, Nasseripour R, Nepali CS, Niccolai S, Niculescu G, Niculescu I, Osipenko M, Ostrovidov AI, Pappalardo LL, Paremuzyan R, Park K, Park S, Petratos GG, Phelps E, Pisano S, Pogorelko O, Pozdniakov S, Procureur S, Protopopescu D, Puckett AJ, Qian X, Qiang Y, Ricco G, Rimal D, Ripani M, Ritchie BG, Rodriguez I, Ron G, Rosner G, Rossi P, Sabatié F, Saha A, Saini MS, Sarty AJ, Sawatzky B, Saylor NA, Schott D, Schulte E, Schumacher RA, Seder E, Seraydaryan H, Shneor R, Smith GD, Sokhan D, Sparveris N, Stepanyan SS, Stepanyan S, Stoler P, Subedi R, Sulkosky V, Taiuti M, Tang W, Taylor CE, Tkachenko S, Ungaro M, Vernarsky B, Vineyard MF, Voskanyan H, Voutier E, Walford NK, Wang Y, Watts DP, Weinstein LB, Weygand DP, Wojtsekhowski B, Wood MH, Yan X, Yao H, Zachariou N, Zhan X, Zhang J, Zhao ZW, Zheng X, and Zonta I

Abstract

We have measured cross sections for the γ(3)He → pd reaction at photon energies of 0.4-1.4 GeV and a center-of-mass angle of 90°. We observe dimensional scaling above 0.7 GeV at this center-of-mass angle. This is the first observation of dimensional scaling in the photodisintegration of a nucleus heavier than the deuteron.

Published
2013
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32. Measurement of exclusive π(0) electroproduction structure functions and their relationship to transverse generalized parton distributions.

Author

Bedlinskiy I, Kubarovsky V, Niccolai S, Stoler P, Adhikari KP, Aghasyan M, Amaryan MJ, Anghinolfi M, Avakian H, Baghdasaryan H, Ball J, Baltzell NA, Battaglieri M, Bennett RP, Biselli AS, Bookwalter C, Boiarinov S, Briscoe WJ, Brooks WK, Burkert VD, Carman DS, Celentano A, Chandavar S, Charles G, Contalbrigo M, Crede V, D'Angelo A, Daniel A, Dashyan N, De Vita R, De Sanctis E, Deur A, Djalali C, Doughty D, Dupre R, Egiyan H, El Alaoui A, El Fassi L, Elouadrhiri L, Eugenio P, Fedotov G, Fegan S, Fleming JA, Forest TA, Fradi A, Garçon M, Gevorgyan N, Giovanetti KL, Girod FX, Gohn W, Gothe RW, Graham L, Griffioen KA, Guegan B, Guidal M, Guo L, Hafidi K, Hakobyan H, Hanretty C, Heddle D, Hicks K, Holtrop M, Ilieva Y, Ireland DG, Ishkhanov BS, Isupov EL, Jo HS, Joo K, Keller D, Khandaker M, Khetarpal P, Kim A, Kim W, Klein FJ, Koirala S, Kubarovsky A, Kuhn SE, Kuleshov SV, Kvaltine ND, Livingston K, Lu HY, MacGregor IJ, Mao Y, Markov N, Martinez D, Mayer M, McKinnon B, Meyer CA, Mineeva T, Mirazita M, Mokeev V, Moutarde H, Munevar E, Munoz Camacho C, Nadel-Turonski P, Niculescu G, Niculescu I, Osipenko M, Ostrovidov AI, Pappalardo LL, Paremuzyan R, Park K, Park S, Pasyuk E, Anefalos Pereira S, Phelps E, Pisano S, Pogorelko O, Pozdniakov S, Price JW, Procureur S, Prok Y, Protopopescu D, Puckett AJ, Raue BA, Ricco G, Rimal D, Ripani M, Rosner G, Rossi P, Sabatié F, Saini MS, Salgado C, Saylor N, Schott D, Schumacher RA, Seder E, Seraydaryan H, Sharabian YG, Smith GD, Sober DI, Sokhan D, Stepanyan SS, Stepanyan S, Strauch S, Taiuti M, Tang W, Taylor CE, Tian Y, Tkachenko S, Ungaro M, Vineyard MF, Vlassov A, Voskanyan H, Voutier E, Walford NK, Watts DP, Weinstein LB, Weygand DP, Wood MH, Zachariou N, Zhang J, Zhao ZW, and Zonta I

Abstract

Exclusive π(0) electroproduction at a beam energy of 5.75 GeV has been measured with the Jefferson Lab CLAS spectrometer. Differential cross sections were measured at more than 1800 kinematic values in Q(2), x(B), t, and ϕ(π), in the Q(2) range from 1.0 to 4.6  GeV(2), -t up to 2  GeV(2), and x(B) from 0.1 to 0.58. Structure functions σ(T)+ϵσ(L), σ(TT), and σ(LT) were extracted as functions of t for each of 17 combinations of Q(2) and x(B). The data were compared directly with two handbag-based calculations including both longitudinal and transversity generalized parton distributions (GPDs). Inclusion of only longitudinal GPDs very strongly underestimates σ(T)+ϵσ(L) and fails to account for σ(TT) and σ(LT), while inclusion of transversity GPDs brings the calculations into substantially better agreement with the data. There is very strong sensitivity to the relative contributions of nucleon helicity-flip and helicity nonflip processes. The results confirm that exclusive π(0) electroproduction offers direct experimental access to the transversity GPDs.

Published
2012
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33. Measurement of the neutron F2 structure function via spectator tagging with CLAS.

Author

Baillie N, Tkachenko S, Zhang J, Bosted P, Bültmann S, Christy ME, Fenker H, Griffioen KA, Keppel CE, Kuhn SE, Melnitchouk W, Tvaskis V, Adhikari KP, Adikaram D, Aghasyan M, Amaryan MJ, Anghinolfi M, Arrington J, Avakian H, Baghdasaryan H, Battaglieri M, Biselli AS, Branford D, Briscoe WJ, Brooks WK, Burkert VD, Carman DS, Celentano A, Chandavar S, Charles G, Cole PL, Contalbrigo M, Crede V, D'Angelo A, Daniel A, Dashyan N, De Vita R, De Sanctis E, Deur A, Dey B, Djalali C, Dodge G, Domingo J, Doughty D, Dupre R, Dutta D, Ent R, Egiyan H, El Alaoui A, El Fassi L, Elouadrhiri L, Eugenio P, Fedotov G, Fegan S, Fradi A, Gabrielyan MY, Gevorgyan N, Gilfoyle GP, Giovanetti KL, Girod FX, Gohn W, Golovatch E, Gothe RW, Graham L, Guegan B, Guidal M, Guler N, Guo L, Hafidi K, Heddle D, Hicks K, Holtrop M, Hungerford E, Hyde CE, Ilieva Y, Ireland DG, Ispiryan M, Isupov EL, Jawalkar SS, Jo HS, Kalantarians N, Khandaker M, Khetarpal P, Kim A, Kim W, King PM, Klein A, Klein FJ, Klimenko A, Kubarovsky V, Kuleshov SV, Kvaltine ND, Livingston K, Lu HY, MacGregor IJ, Mao Y, Markov N, McKinnon B, Mineeva T, Morrison B, Moutarde H, Munevar E, Nadel-Turonski P, Ni A, Niccolai S, Niculescu I, Niculescu G, Osipenko M, Ostrovidov AI, Pappalardo L, Park K, Park S, Pasyuk E, Anefalos Pereira S, Pisano S, Pozdniakov S, Price JW, Procureur S, Prok Y, Protopopescu D, Raue BA, Ricco G, Rimal D, Ripani M, Rosner G, Rossi P, Sabatié F, Saini MS, Salgado C, Schott D, Schumacher RA, Seder E, Sharabian YG, Sober DI, Sokhan D, Stepanyan S, Stepanyan SS, Stoler P, Strauch S, Taiuti M, Tang W, Ungaro M, Vineyard MF, Voutier E, Watts DP, Weinstein LB, Weygand DP, Wood MH, Zana L, and Zhao B

Abstract

We report on the first measurement of the F(2) structure function of the neutron from the semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to ≲100 MeV/c and their angles to ≳100° relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The F(2)(n) data collected cover the nucleon-resonance and deep-inelastic regions over a wide range of Bjorken x for 0.65

Published
2012
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