Author: "N, Liyanage" / Journal: physical review letters - Searchworks@Jio Institute Digital Library Search Results

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56 results on '"N, Liyanage"'

1. Precision Measurement of the p(e,e^{'}p)π^{0} Reaction at Threshold

Author: K, Chirapatpimol, M H, Shabestari, R A, Lindgren, L C, Smith, J R M, Annand, D W, Higinbotham, B, Moffit, V, Nelyubin, B E, Norum, K, Allada, K, Aniol, K, Ardashev, D S, Armstrong, R A, Arndt, F, Benmokhtar, A M, Bernstein, W, Bertozzi, W J, Briscoe, L, Bimbot, A, Camsonne, J-P, Chen, S, Choi, E, Chudakov, E, Cisbani, F, Cusanno, M M, Dalton, C, Dutta, K, Egiyan, C, Fernàndez-Ramìrez, R, Feuerbach, K G, Fissum, S, Frullani, F, Garibaldi, O, Gayou, R, Gilman, S, Gilad, J, Goity, J, Gomez, B, Hahn, D, Hamilton, J-O, Hansen, J, Huang, R, Igarashi, D, Ireland, C W, de Jager, X, Jin, X, Jiang, T, Jinasundera, J, Kellie, C E, Keppel, N, Kolb, J, LeRose, N, Liyanage, K, Livingston, D, McNulty, L, Mercado, R, Michaels, M, Mihovilovič, S, Qian, X, Qian, S, Mailyan, V, Mamyan, S, Marrone, P, Monaghan, S, Nanda, C F, Perdrisat, E, Piasetzky, D, Protopopescu, V, Punjabi, Y, Qiang, I A, Rachek, A, Rakhman, S, Riordan, G, Ron, G, Rosner, A, Saha, B, Sawatzky, A, Shahinyan, S, Širca, N, Sparveris, R R, Subedi, R, Suleiman, I, Strakovsky, V, Sulkosky, J, Moinelo, H, Voskanyan, K, Wang, Y, Wang, J, Watson, D, Watts, B, Wojtsekhowski, R L, Workman, H, Yao, X, Zhan, and Y, Zhang
Abstract: New results are reported from a measurement of π^{0} electroproduction near threshold using the p(e,e^{'}p)π^{0} reaction. The experiment was designed to determine precisely the energy dependence of s- and p-wave electromagnetic multipoles as a stringent test of the predictions of chiral perturbation theory (ChPT). The data were taken with an electron beam energy of 1192 MeV using a two-spectrometer setup in Hall A at Jefferson Lab. For the first time, complete coverage of the ϕ_{π}^{*} and θ_{π}^{*} angles in the pπ^{0} center of mass was obtained for invariant energies above threshold from 0.5 up to 15 MeV. The 4-momentum transfer Q^{2} coverage ranges from 0.05 to 0.155 (GeV/c)^{2} in fine steps. A simple phenomenological analysis of our data shows strong disagreement with p-wave predictions from ChPT for Q^{2}0.07 (GeV/c)^{2}, while the s-wave predictions are in reasonable agreement.
Published: 2015

2. Precision measurement of the neutron twist-3 matrix element d(2)(n): probing color forces

Author: M, Posik, D, Flay, D S, Parno, K, Allada, W, Armstrong, T, Averett, F, Benmokhtar, W, Bertozzi, A, Camsonne, M, Canan, G D, Cates, C, Chen, J-P, Chen, S, Choi, E, Chudakov, F, Cusanno, M M, Dalton, W, Deconinck, C W, de Jager, X, Deng, A, Deur, C, Dutta, L, El Fassi, G B, Franklin, M, Friend, H, Gao, F, Garibaldi, S, Gilad, R, Gilman, O, Glamazdin, S, Golge, J, Gomez, L, Guo, O, Hansen, D W, Higinbotham, T, Holmstrom, J, Huang, C, Hyde, H F, Ibrahim, X, Jiang, G, Jin, J, Katich, A, Kelleher, A, Kolarkar, W, Korsch, G, Kumbartzki, J J, LeRose, R, Lindgren, N, Liyanage, E, Long, A, Lukhanin, V, Mamyan, D, McNulty, Z-E, Meziani, R, Michaels, M, Mihovilovič, B, Moffit, N, Muangma, S, Nanda, A, Narayan, V, Nelyubin, B, Norum, Nuruzzaman, Y, Oh, J C, Peng, X, Qian, Y, Qiang, A, Rakhman, S, Riordan, A, Saha, B, Sawatzky, M H, Shabestari, A, Shahinyan, S, Širca, P, Solvignon, R, Subedi, V, Sulkosky, W A, Tobias, W, Troth, D, Wang, Y, Wang, B, Wojtsekhowski, X, Yan, H, Yao, Y, Ye, Z, Ye, L, Yuan, X, Zhan, Y, Zhang, Y-W, Zhang, B, Zhao, and X, Zheng
Abstract: Double-spin asymmetries and absolute cross sections were measured at large Bjorken x (0.25≤x≤0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized (3)He target. In this dedicated experiment, the spin structure function g(2)((3)He) was determined with precision at large x, and the neutron twist-3 matrix element d(2)(n) was measured at ⟨Q(2)⟩ of 3.21 and 4.32 GeV(2)/c(2), with an absolute precision of about 10(-5). Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at ⟨Q(2)⟩=5 GeV(2)/c(2). Combining d(2)(n) and a newly extracted twist-4 matrix element f(2)(n), the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 30 MeV/fm in magnitude.
Published: 2014

3. GEp/GMpRatio by Polarization Transfer ine→p→ep→

Author: M. K. Jones, K. A. Aniol, F. T. Baker, J. Berthot, P. Y. Bertin, W. Bertozzi, A. Besson, L. Bimbot, W. U. Boeglin, E. J. Brash, D. Brown, J. R. Calarco, L. S. Cardman, C.-C. Chang, J.-P. Chen, E. Chudakov, S. Churchwell, E. Cisbani, D. S. Dale, R. De Leo, A. Deur, B. Diederich, J. J. Domingo, M. B. Epstein, L. A. Ewell, K. G. Fissum, A. Fleck, H. Fonvieille, S. Frullani, J. Gao, F. Garibaldi, A. Gasparian, G. Gerstner, S. Gilad, R. Gilman, A. Glamazdin, C. Glashausser, J. Gomez, V. Gorbenko, A. Green, J.-O. Hansen, C. R. Howell, G. M. Huber, M. Iodice, C. W. de Jager, S. Jaminion, X. Jiang, W. Kahl, J. J. Kelly, M. Khayat, L. H. Kramer, G. Kumbartzki, M. Kuss, E. Lakuriki, G. Lavessière, J. J. LeRose, M. Liang, R. A. Lindgren, N. Liyanage, G. J. Lolos, R. Macri, R. Madey, S. Malov, D. J. Margaziotis, P. Markowitz, K. McCormick, J. I. McIntyre, R. L. J. van der Meer, R. Michaels, B. D. Milbrath, J. Y. Mougey, S. K. Nanda, E. A. J. M. Offermann, Z. Papandreou, C. F. Perdrisat, G. G. Petratos, N. M. Piskunov, R. I. Pomatsalyuk, D. L. Prout, V. Punjabi, G. Quéméner, R. D. Ransome, B. A. Raue, Y. Roblin, R. Roche, G. Rutledge, P. M. Rutt, A. Saha, T. Saito, A. J. Sarty, T. P. Smith, P. Sorokin, S. Strauch, R. Suleiman, K. Takahashi, J. A. Templon, L. Todor, P. E. Ulmer, G. M. Urciuoli, P. Vernin, B. Vlahovic, H. Voskanyan, K. Wijesooriya, B. B. Wojtsekhowski, R. J. Woo, F. Xiong, G. D. Zainea, and Z.-L. Zhou
Subjects: Elastic scattering, Physics, Proton, 010308 nuclear & particles physics, Proton magnetic moment, General Physics and Astronomy, Electron, Polarization (waves), 01 natural sciences, Charged particle, Nuclear physics, Magnetization, 0103 physical sciences, Magnetic form factor, Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract: The ratio of the proton's elastic electromagnetic form factors was obtained by measuring the transverse and longitudinal polarizations of recoiling protons from the elastic scattering of polarized electrons with unpolarized protons. The ratio of the electric to magnetic form factor is proportional to the ratio of the transverse to longitudinal recoil polarizations. The ratio was measured over a range of four-momentum transfer squared between 0.5 and 3.5 GeV-squared. Simultaneous measurement of transverse and longitudinal polarizations in a polarimeter provides good control of the systematic uncertainty. The results for the ratio of the proton's electric to magnetic form factors show a systematic decrease with increasing four momentum squared, indicating for the first time a marked difference in the spatial distribution of charge and magnetization currents in the proton.
Published: 2000
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4. Measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the reaction (3)He(↑)(e,e')X

Author: J, Katich, X, Qian, Y X, Zhao, K, Allada, K, Aniol, J R M, Annand, T, Averett, F, Benmokhtar, W, Bertozzi, P C, Bradshaw, P, Bosted, A, Camsonne, M, Canan, G D, Cates, C, Chen, J-P, Chen, W, Chen, K, Chirapatpimol, E, Chudakov, E, Cisbani, J C, Cornejo, F, Cusanno, M M, Dalton, W, Deconinck, C W, de Jager, R, De Leo, X, Deng, A, Deur, H, Ding, P A M, Dolph, C, Dutta, D, Dutta, L, El Fassi, S, Frullani, H, Gao, F, Garibaldi, D, Gaskell, S, Gilad, R, Gilman, O, Glamazdin, S, Golge, L, Guo, D, Hamilton, O, Hansen, D W, Higinbotham, T, Holmstrom, J, Huang, M, Huang, H F, Ibrahim, M, Iodice, X, Jiang, G, Jin, M K, Jones, A, Kelleher, W, Kim, A, Kolarkar, W, Korsch, J J, LeRose, X, Li, Y, Li, R, Lindgren, N, Liyanage, E, Long, H-J, Lu, D J, Margaziotis, P, Markowitz, S, Marrone, D, McNulty, Z-E, Meziani, R, Michaels, B, Moffit, C, Muñoz Camacho, S, Nanda, A, Narayan, V, Nelyubin, B, Norum, Y, Oh, M, Osipenko, D, Parno, J C, Peng, S K, Phillips, M, Posik, A J R, Puckett, Y, Qiang, A, Rakhman, R D, Ransome, S, Riordan, A, Saha, B, Sawatzky, E, Schulte, A, Shahinyan, M H, Shabestari, S, Širca, S, Stepanyan, R, Subedi, V, Sulkosky, L-G, Tang, A, Tobias, G M, Urciuoli, I, Vilardi, K, Wang, Y, Wang, B, Wojtsekhowski, X, Yan, H, Yao, Y, Ye, Z, Ye, L, Yuan, X, Zhan, Y, Zhang, Y-W, Zhang, B, Zhao, X, Zheng, L, Zhu, X, Zhu, and X, Zong
Abstract: We report the first measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the inclusive reaction 3)He(↑)(e,e')X on a polarized (3)He gas target. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation but can be nonzero if two-photon-exchange contributions are included. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.7W2.9 GeV, 1.0Q(2)4.0 GeV(2) and 0.16x0.65. Neutron asymmetries were extracted using the effective nucleon polarization and measured proton-to-(3)He cross-section ratios. The measured neutron asymmetries are negative with an average value of (-1.09±0.38)×10(-2) for invariant mass W2 GeV, which is nonzero at the 2.89σ level. Our measured asymmetry agrees both in sign and magnitude with a two-photon-exchange model prediction that uses input from the Sivers transverse momentum distribution obtained from semi-inclusive deep-inelastic scattering.
Published: 2013

5. Beam-target double-spin asymmetry A{LT} in charged pion production from deep inelastic scattering on a transversely polarized {3}He target at 1.4Q{2}2.7 GeV{2}

Author: J, Huang, K, Allada, C, Dutta, J, Katich, X, Qian, Y, Wang, Y, Zhang, K, Aniol, J R M, Annand, T, Averett, F, Benmokhtar, W, Bertozzi, P C, Bradshaw, P, Bosted, A, Camsonne, M, Canan, G D, Cates, C, Chen, J-P, Chen, W, Chen, K, Chirapatpimol, E, Chudakov, E, Cisbani, J C, Cornejo, F, Cusanno, M M, Dalton, W, Deconinck, C W, de Jager, R, De Leo, X, Deng, A, Deur, H, Ding, P A M, Dolph, D, Dutta, L, El Fassi, S, Frullani, H, Gao, F, Garibaldi, D, Gaskell, S, Gilad, R, Gilman, O, Glamazdin, S, Golge, L, Guo, D, Hamilton, O, Hansen, D W, Higinbotham, T, Holmstrom, M, Huang, H F, Ibrahim, M, Iodice, X, Jiang, G, Jin, M K, Jones, A, Kelleher, W, Kim, A, Kolarkar, W, Korsch, J J, Lerose, X, Li, Y, Li, R, Lindgren, N, Liyanage, E, Long, H-J, Lu, D J, Margaziotis, P, Markowitz, S, Marrone, D, McNulty, Z-E, Meziani, R, Michaels, B, Moffit, C, Muñoz Camacho, S, Nanda, A, Narayan, V, Nelyubin, B, Norum, Y, Oh, M, Osipenko, D, Parno, J C, Peng, S K, Phillips, M, Posik, A J R, Puckett, Y, Qiang, A, Rakhman, R D, Ransome, S, Riordan, A, Saha, B, Sawatzky, E, Schulte, A, Shahinyan, M H, Shabestari, S, Sirca, S, Stepanyan, R, Subedi, V, Sulkosky, L-G, Tang, A, Tobias, G M, Urciuoli, I, Vilardi, K, Wang, B, Wojtsekhowski, X, Yan, H, Yao, Y, Ye, Z, Ye, L, Yuan, X, Zhan, Y-W, Zhang, B, Zhao, X, Zheng, L, Zhu, X, Zhu, and X, Zong
Abstract: We report the first measurement of the double-spin asymmetry A{LT} for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized {3}He target. The kinematics focused on the valence quark region, 0.16x0.35 with 1.4Q{2}2.7 GeV{2}. The corresponding neutron A{LT} asymmetries were extracted from the measured {3}He asymmetries and proton over {3}He cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function g{1T}{q} and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for π{-} production on {3}He and the neutron, while our π{+} asymmetries are consistent with zero.
Published: 2011

6. Single spin asymmetries in charged pion production from semi-inclusive deep inelastic scattering on a transversely polarized 3He Target at Q2 = 1.4-2.7 GeV2

Author: X, Qian, K, Allada, C, Dutta, J, Huang, J, Katich, Y, Wang, Y, Zhang, K, Aniol, J R M, Annand, T, Averett, F, Benmokhtar, W, Bertozzi, P C, Bradshaw, P, Bosted, A, Camsonne, M, Canan, G D, Cates, C, Chen, J-P, Chen, W, Chen, K, Chirapatpimol, E, Chudakov, E, Cisbani, J C, Cornejo, F, Cusanno, M M, Dalton, W, Deconinck, C W, de Jager, R, De Leo, X, Deng, A, Deur, H, Ding, P A M, Dolph, D, Dutta, L, El Fassi, S, Frullani, H, Gao, F, Garibaldi, D, Gaskell, S, Gilad, R, Gilman, O, Glamazdin, S, Golge, L, Guo, D, Hamilton, O, Hansen, D W, Higinbotham, T, Holmstrom, M, Huang, H F, Ibrahim, M, Iodice, X, Jiang, G, Jin, M K, Jones, A, Kelleher, W, Kim, A, Kolarkar, W, Korsch, J J, LeRose, X, Li, Y, Li, R, Lindgren, N, Liyanage, E, Long, H-J, Lu, D J, Margaziotis, P, Markowitz, S, Marrone, D, McNulty, Z-E, Meziani, R, Michaels, B, Moffit, C Muñoz, Camacho, S, Nanda, A, Narayan, V, Nelyubin, B, Norum, Y, Oh, M, Osipenko, D, Parno, J C, Peng, S K, Phillips, M, Posik, A J R, Puckett, Y, Qiang, A, Rakhman, R D, Ransome, S, Riordan, A, Saha, B, Sawatzky, E, Schulte, A, Shahinyan, M H, Shabestari, S, Sirca, S, Stepanyan, R, Subedi, V, Sulkosky, L-G, Tang, A, Tobias, G M, Urciuoli, I, Vilardi, K, Wang, B, Wojtsekhowski, X, Yan, H, Yao, Y, Ye, Z, Ye, L, Yuan, X, Zhan, Y-W, Zhang, B, Zhao, X, Zheng, L, Zhu, X, Zhu, and X, Zong
Abstract: We report the first measurement of target single spin asymmetries in the semi-inclusive (3)He(e,e'π(±))X reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.16x0.35 with 1.4Q(2)2.7 GeV(2). The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The π(±) Collins moments for (3)He are consistent with zero, except for the π(+) moment at x = 0.35, which deviates from zero by 2.3σ. While the π(-) Sivers moments are consistent with zero, the π(+) Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and measured cross section ratios of proton to (3)He, and are largely consistent with the predictions of phenomenological fits and quark model calculations.
Published: 2011

7. Measurements of the Electric Form Factor of the Neutron up toQ2=3.4 GeV2Using the Reaction3He→(e→,e′n)pp

Author: S. Riordan, S. Abrahamyan, B. Craver, A. Kelleher, A. Kolarkar, J. Miller, G. D. Cates, N. Liyanage, B. Wojtsekhowski, A. Acha, K. Allada, B. Anderson, K. A. Aniol, J. R. M. Annand, J. Arrington, T. Averett, A. Beck, M. Bellis, W. Boeglin, H. Breuer, J. R. Calarco, A. Camsonne, J. P. Chen, E. Chudakov, L. Coman, B. Crowe, F. Cusanno, D. Day, P. Degtyarenko, P. A. M. Dolph, C. Dutta, C. Ferdi, C. Fernández-Ramírez, R. Feuerbach, L. M. Fraile, G. Franklin, S. Frullani, S. Fuchs, F. Garibaldi, N. Gevorgyan, R. Gilman, A. Glamazdin, J. Gomez, K. Grimm, J.-O. Hansen, J. L. Herraiz, D. W. Higinbotham, R. Holmes, T. Holmstrom, D. Howell, C. W. de Jager, X. Jiang, M. K. Jones, J. Katich, L. J. Kaufman, M. Khandaker, J. J. Kelly, D. Kiselev, W. Korsch, J. LeRose, R. Lindgren, P. Markowitz, D. J. Margaziotis, S. May-Tal Beck, S. Mayilyan, K. McCormick, Z.-E. Meziani, R. Michaels, B. Moffit, S. Nanda, V. Nelyubin, T. Ngo, D. M. Nikolenko, B. Norum, L. Pentchev, C. F. Perdrisat, E. Piasetzky, R. Pomatsalyuk, D. Protopopescu, A. J. R. Puckett, V. A. Punjabi, X. Qian, Y. Qiang, B. Quinn, I. Rachek, R. D. Ransome, P. E. Reimer, B. Reitz, J. Roche, G. Ron, O. Rondon, G. Rosner, A. Saha, M. M. Sargsian, B. Sawatzky, J. Segal, M. Shabestari, A. Shahinyan, Yu. Shestakov, J. Singh, S. Širca, P. Souder, S. Stepanyan, V. Stibunov, V. Sulkosky, S. Tajima, W. A. Tobias, J. M. Udias, G. M. Urciuoli, B. Vlahovic, H. Voskanyan, K. Wang, F. R. Wesselmann, J. R. Vignote, S. A. Wood, J. Wright, H. Yao, and X. Zhu
Subjects: Physics, Momentum transfer, Electric form factor, General Physics and Astronomy, Neutron, Atomic physics, Polarized target
Abstract: The electric form factor of the neutron was determined from studies of the reaction ${}^{3}\stackrel{\ensuremath{\rightarrow}}{\mathrm{He}}(\stackrel{\ensuremath{\rightarrow}}{e},{e}^{\ensuremath{'}}n)pp$ in quasielastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear polarization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. More than doubling the ${Q}^{2}$ range over which it is known, we find ${G}_{E}^{n}=0.0236\ifmmode\pm\else\textpm\fi{}0.0017(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.0026(\mathrm{syst})$, $0.0208\ifmmode\pm\else\textpm\fi{}0.0024\ifmmode\pm\else\textpm\fi{}0.0019$, and $0.0147\ifmmode\pm\else\textpm\fi{}0.0020\ifmmode\pm\else\textpm\fi{}0.0014$ for ${Q}^{2}=1.72$, 2.48, and $3.41\text{ }\text{ }{\mathrm{GeV}}^{2}$, respectively.
Published: 2010
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8. Measurements of the electric form factor of the neutron up to Q2=3.4 GeV2 using the reaction 3He(e,e'n)pp

Author: S, Riordan, S, Abrahamyan, B, Craver, A, Kelleher, A, Kolarkar, J, Miller, G D, Cates, N, Liyanage, B, Wojtsekhowski, A, Acha, K, Allada, B, Anderson, K A, Aniol, J R M, Annand, J, Arrington, T, Averett, A, Beck, M, Bellis, W, Boeglin, H, Breuer, J R, Calarco, A, Camsonne, J P, Chen, E, Chudakov, L, Coman, B, Crowe, F, Cusanno, D, Day, P, Degtyarenko, P A M, Dolph, C, Dutta, C, Ferdi, C, Fernández-Ramírez, R, Feuerbach, L M, Fraile, G, Franklin, S, Frullani, S, Fuchs, F, Garibaldi, N, Gevorgyan, R, Gilman, A, Glamazdin, J, Gomez, K, Grimm, J-O, Hansen, J L, Herraiz, D W, Higinbotham, R, Holmes, T, Holmstrom, D, Howell, C W, de Jager, X, Jiang, M K, Jones, J, Katich, L J, Kaufman, M, Khandaker, J J, Kelly, D, Kiselev, W, Korsch, J, LeRose, R, Lindgren, P, Markowitz, D J, Margaziotis, S May-Tal, Beck, S, Mayilyan, K, McCormick, Z-E, Meziani, R, Michaels, B, Moffit, S, Nanda, V, Nelyubin, T, Ngo, D M, Nikolenko, B, Norum, L, Pentchev, C F, Perdrisat, E, Piasetzky, R, Pomatsalyuk, D, Protopopescu, A J R, Puckett, V A, Punjabi, X, Qian, Y, Qiang, B, Quinn, I, Rachek, R D, Ransome, P E, Reimer, B, Reitz, J, Roche, G, Ron, O, Rondon, G, Rosner, A, Saha, M M, Sargsian, B, Sawatzky, J, Segal, M, Shabestari, A, Shahinyan, Yu, Shestakov, J, Singh, S, Sirca, P, Souder, S, Stepanyan, V, Stibunov, V, Sulkosky, S, Tajima, W A, Tobias, J M, Udias, G M, Urciuoli, B, Vlahovic, H, Voskanyan, K, Wang, F R, Wesselmann, J R, Vignote, S A, Wood, J, Wright, H, Yao, and X, Zhu
Abstract: The electric form factor of the neutron was determined from studies of the reaction 3He(e,e'n)pp in quasielastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear polarization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. More than doubling the Q2 range over which it is known, we find G(E)(n)=0.0236±0.0017(stat)±0.0026(syst), 0.0208±0.0024±0.0019, and 0.0147±0.0020±0.0014 for Q(2)=1.72, 2.48, and 3.41 GeV2, respectively.
Published: 2010

9. Precision measurements of the nucleon strange form factors at Q2 approximately 0.1 GeV2

Author: A, Acha, K A, Aniol, D S, Armstrong, J, Arrington, T, Averett, S L, Bailey, J, Barber, A, Beck, H, Benaoum, J, Benesch, P Y, Bertin, P, Bosted, F, Butaru, E, Burtin, G D, Cates, Y-C, Chao, J-P, Chen, E, Chudakov, E, Cisbani, B, Craver, F, Cusanno, R, De Leo, P, Decowski, A, Deur, R J, Feuerbach, J M, Finn, S, Frullani, S A, Fuchs, K, Fuoti, R, Gilman, L E, Glesener, K, Grimm, J M, Grames, J O, Hansen, J, Hansknecht, D W, Higinbotham, R, Holmes, T, Holmstrom, H, Ibrahim, C W, de Jager, X, Jiang, J, Katich, L J, Kaufman, A, Kelleher, P M, King, A, Kolarkar, S, Kowalski, E, Kuchina, K S, Kumar, L, Lagamba, P, LaViolette, J, LeRose, R A, Lindgren, D, Lhuillier, N, Liyanage, D J, Margaziotis, P, Markowitz, D G, Meekins, Z-E, Meziani, R, Michaels, B, Moffit, S, Nanda, V, Nelyubin, K, Otis, K D, Paschke, S K, Phillips, M, Poelker, R, Pomatsalyuk, M, Potokar, Y, Prok, A, Puckett, X, Qian, Y, Qiang, B, Reitz, J, Roche, A, Saha, B, Sawatzky, J, Singh, K, Slifer, S, Sirca, R, Snyder, P, Solvignon, P A, Souder, M L, Stutzman, R, Subedi, R, Suleiman, V, Sulkosky, W A, Tobias, P E, Ulmer, G M, Urciuoli, K, Wang, A, Whitbeck, R, Wilson, B, Wojtsekhowski, H, Yao, Y, Ye, X, Zhan, X, Zheng, S, Zhou, and V, Ziskin
Abstract: We report new measurements of the parity-violating asymmetry A(PV) in elastic scattering of 3 GeV electrons off hydrogen and 4He targets withtheta(lab)approximately 6.0 degrees . The 4He result is A(PV)=(+6.40+/-0.23(stat)+/-0.12(syst))x10(-6). The hydrogen result is A(PV)=(-1.58+/-0.12(stat)+/-0.04(syst))x10(-6). These results significantly improve constraints on the electric and magnetic strange form factors G(E)(s) and G(M)(s). We extract G(E)(s)=0.002+/-0.014+/-0.007 atQ(2)=0.077 GeV2, and G(E)(s)+0.09G(M)(s)=0.007+/-0.011+/-0.006 atQ(2)=0.109 GeV2, providing new limits on the role of strange quarks in the nucleon charge and magnetization distributions.
Published: 2006

10. Parity-Violating Electron Scattering fromHe4and the Strange Electric Form Factor of the Nucleon

Author: K. A. Aniol, D. S. Armstrong, T. Averett, H. Benaoum, P. Y. Bertin, E. Burtin, J. Cahoon, G. D. Cates, C. C. Chang, Y.-C. Chao, J.-P. Chen, Seonho Choi, E. Chudakov, B. Craver, F. Cusanno, P. Decowski, D. Deepa, C. Ferdi, R. J. Feuerbach, J. M. Finn, S. Frullani, K. Fuoti, F. Garibaldi, R. Gilman, A. Glamazdin, V. Gorbenko, J. M. Grames, J. Hansknecht, D. W. Higinbotham, R. Holmes, T. Holmstrom, T. B. Humensky, H. Ibrahim, C. W. de Jager, X. Jiang, L. J. Kaufman, A. Kelleher, A. Kolarkar, S. Kowalski, K. S. Kumar, D. Lambert, P. LaViolette, J. LeRose, D. Lhuillier, N. Liyanage, D. J. Margaziotis, M. Mazouz, K. McCormick, D. G. Meekins, Z.-E. Meziani, R. Michaels, B. Moffit, P. Monaghan, C. Munoz-Camacho, S. Nanda, V. Nelyubin, D. Neyret, K. D. Paschke, M. Poelker, R. Pomatsalyuk, Y. Qiang, B. Reitz, J. Roche, A. Saha, J. Singh, R. Snyder, P. A. Souder, R. Subedi, R. Suleiman, V. Sulkosky, W. A. Tobias, G. M. Urciuoli, A. Vacheret, E. Voutier, K. Wang, R. Wilson, B. Wojtsekhowski, and X. Zheng
Subjects: Physics, Quark, Particle physics, Magnetic moment, Neutral current, 010308 nuclear & particles physics, Scattering, media_common.quotation_subject, Electroweak interaction, General Physics and Astronomy, 01 natural sciences, Asymmetry, Proton scattering, 0103 physical sciences, 010306 general physics, Parity (mathematics), media_common
Published: 2006
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11. Q2 dependence of the neutron spin structure function g2(n) at low Q2

Author: K, Kramer, D S, Armstrong, T D, Averett, W, Bertozzi, S, Binet, C, Butuceanu, A, Camsonne, G D, Cates, J-P, Chen, Seonho, Choi, E, Chudakov, F, Cusanno, A, Deur, P, Djawotho, D, Dutta, J M, Finn, H, Gao, F, Garibaldi, O, Gayou, R, Gilman, A, Glamazdin, V, Gorbenko, K A, Griffioen, J-O, Hansen, D W, Higinbotham, W, Hinton, T, Horn, C W, de Jager, X, Jiang, W, Korsch, J, LeRose, D, Lhuillier, N, Liyanage, D J, Margaziotis, K, McCormick, Z-E, Meziani, R, Michaels, B, Milbrath, B, Moffit, S, Nanda, C F, Perdrisat, R, Pomatsalyuk, V, Punjabi, B, Reitz, J, Roche, R, Roché, M, Roedelbronn, N, Savvinov, J, Secrest, J, Singh, S, Sirca, K, Slifer, P, Solvignon, D J, Steiner, R, Suleiman, V, Sulkosky, A, Tobias, A, Vacheret, Y, Xiao, X, Zheng, J, Zhou, L, Zhu, X, Zhu, and P A, Zołnierczuk
Subjects: High Energy Physics::Lattice, Nuclear Theory, High Energy Physics::Phenomenology, High Energy Physics::Experiment, Nuclear Experiment
Abstract: We present the first measurement of the Q2 dependence of the neutron spin structure function g2(n) at five kinematic points covering 0.57 (GeV/c)2 < or = Q2 < or = 1.34 (GeV/c)2 at x approximately = 0.2. Though the naive quark-parton model predicts g2 = 0, nonzero values occur in more realistic models of the nucleon which include quark-gluon correlations, finite quark masses, or orbital angular momentum. When scattering from a noninteracting quark, g2(n) can be predicted using next-to-leading order fits to world data for g1(n). Deviations from this prediction provide an opportunity to examine QCD dynamics in nucleon structure. Our results show a positive deviation from this prediction at lower Q2, indicating that contributions such as quark-gluon interactions may be important. Precision data obtained for g1(n) are consistent with next-to-leading order fits to world data.
Published: 2005

12. Measurement of the Generalized Polarizabilities of the Proton in Virtual Compton Scattering atQ2=0.92and1.76 GeV2

Author: G. Laveissière, L. Todor, N. Degrande, S. Jaminion, C. Jutier, R. Di Salvo, L. Van Hoorebeke, L. C. Alexa, B. D. Anderson, K. A. Aniol, K. Arundell, G. Audit, L. Auerbach, F. T. Baker, M. Baylac, J. Berthot, P. Y. Bertin, W. Bertozzi, L. Bimbot, W. U. Boeglin, E. J. Brash, V. Breton, H. Breuer, E. Burtin, J. R. Calarco, L. S. Cardman, C. Cavata, C.-C. Chang, J.-P. Chen, E. Chudakov, E. Cisbani, D. S. Dale, C. W. de Jager, R. De Leo, A. Deur, N. d'Hose, G. E. Dodge, J. J. Domingo, L. Elouadrhiri, M. B. Epstein, L. A. Ewell, J. M. Finn, K. G. Fissum, H. Fonvieille, G. Fournier, B. Frois, S. Frullani, C. Furget, H. Gao, J. Gao, F. Garibaldi, A. Gasparian, S. Gilad, R. Gilman, A. Glamazdin, C. Glashausser, J. Gomez, V. Gorbenko, P. Grenier, P. A. M. Guichon, J. O. Hansen, R. Holmes, M. Holtrop, C. Howell, G. M. Huber, C. E. Hyde-Wright, S. Incerti, M. Iodice, J. Jardillier, M. K. Jones, W. Kahl, S. Kato, A. T. Katramatou, J. J. Kelly, S. Kerhoas, A. Ketikyan, M. Khayat, K. Kino, S. Kox, L. H. Kramer, K. S. Kumar, G. Kumbartzki, M. Kuss, A. Leone, J. J. LeRose, M. Liang, R. A. Lindgren, N. Liyanage, G. J. Lolos, R. W. Lourie, R. Madey, K. Maeda, S. Malov, D. M. Manley, C. Marchand, D. Marchand, D. J. Margaziotis, P. Markowitz, J. Marroncle, J. Martino, K. McCormick, J. McIntyre, S. Mehrabyan, F. Merchez, Z. E. Meziani, R. Michaels, G. W. Miller, J. Y. Mougey, S. K. Nanda, D. Neyret, E. A. J. M. Offermann, Z. Papandreou, B. Pasquini, C. F. Perdrisat, R. Perrino, G. G. Petratos, S. Platchkov, R. Pomatsalyuk, D. L. Prout, V. A. Punjabi, T. Pussieux, G. Quémenér, R. D. Ransome, O. Ravel, J. S. Real, F. Renard, Y. Roblin, D. Rowntree, G. Rutledge, P. M. Rutt, A. Saha, T. Saito, A. J. Sarty, A. Serdarevic, T. Smith, G. Smirnov, K. Soldi, P. Sorokin, P. A. Souder, R. Suleiman, J. A. Templon, T. Terasawa, R. Tieulent, E. Tomasi-Gustaffson, H. Tsubota, H. Ueno, P. E. Ulmer, G. M. Urciuoli, M. Vanderhaeghen, R. Van De Vyver, R. L. J. Van der Meer, P. Vernin, B. Vlahovic, H. Voskanyan, E. Voutier, J. W. Watson, L. B. Weinstein, K. Wijesooriya, R. Wilson, B. B. Wojtsekhowski, D. G. Zainea, W-M. Zhang, J. Zhao, and Z.-L. Zhou
Subjects: Physics, Proton, 010308 nuclear & particles physics, Scattering, Momentum transfer, Compton scattering, General Physics and Astronomy, 01 natural sciences, 7. Clean energy, Nuclear physics, Paramagnetism, Dipole, Pion, Polarizability, 0103 physical sciences, Atomic physics, 010306 general physics
Abstract: We report a virtual Compton scattering study of the proton at low c.m. energies. We have determined the structure functions P(LL)-P(TT)/epsilon and P(LT), and the electric and magnetic generalized polarizabilities (GPs) alpha(E)(Q2) and beta(M)(Q2) at momentum transfer Q(2)=0.92 and 1.76 GeV2. The electric GP shows a strong falloff with Q2, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a falloff; this can be interpreted as the dominance of a long-distance diamagnetic pion cloud at low Q2, compensated at higher Q2 by a paramagnetic contribution from piN intermediate states.
Published: 2004
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13. Quasielastic 3He(e,e'p)2H reaction at Q2 = 1.5 GeV2 for recoil momenta up to 1 GeV/c

Author: M M, Rvachev, F, Benmokhtar, E, Penel-Nottaris, K A, Aniol, W, Bertozzi, W U, Boeglin, F, Butaru, J R, Calarco, Z, Chai, C C, Chang, J-P, Chen, E, Chudakov, E, Cisbani, A, Cochran, J, Cornejo, S, Dieterich, P, Djawotho, W, Duran, M B, Epstein, J M, Finn, K G, Fissum, A, Frahi-Amroun, S, Frullani, C, Furget, F, Garibaldi, O, Gayou, S, Gilad, R, Gilman, C, Glashausser, J-O, Hansen, D W, Higinbotham, A, Hotta, B, Hu, M, Iodice, R, Iomni, C W, de Jager, X, Jiang, M K, Jones, J J, Kelly, S, Kox, M, Kuss, J M, Laget, R, De Leo, J J, Lerose, E, Liatard, R, Lindgren, N, Liyanage, R W, Lourie, S, Malov, D J, Margaziotis, P, Markowitz, F, Merchez, R, Michaels, J, Mitchell, J, Mougey, C F, Perdrisat, V A, Punjabi, G, Quéméner, R D, Ransome, J-S, Réal, R, Roché, F, Sabatié, A, Saha, D, Simon, S, Strauch, R, Suleiman, T, Tamae, J A, Templon, R, Tieulent, H, Ueno, P E, Ulmer, G M, Urciuoli, E, Voutier, K, Wijesooriya, and B, Wojtsekhowski
Abstract: We have studied the quasielastic 3He(e,e(')p)2H reaction in perpendicular coplanar kinematics, with the energy and the momentum transferred by the electron fixed at 840 MeV and 1502 MeV/c, respectively. The 3He(e,e(')p)2H cross section was measured for missing momenta up to 1000 MeV/c, while the A(TL) asymmetry was extracted for missing momenta up to 660 MeV/c. For missing momenta up to 150 MeV/c, the cross section is described by variational calculations using modern 3He wave functions. For missing momenta from 150 to 750 MeV/c, strong final-state interaction effects are observed. Near 1000 MeV/c, the experimental cross section is more than an order of magnitude larger than predicted by available theories. The A(TL) asymmetry displays characteristic features of broken factorization with a structure that is similar to that generated by available models.
Published: 2004

14. Precision measurement of the neutron spin asymmetryA(n)(1) and spin-flavor decomposition in the valence quark region

Author: X, Zheng, K, Aniol, D S, Armstrong, T D, Averett, W, Bertozzi, S, Binet, E, Burtin, E, Busato, C, Butuceanu, J, Calarco, A, Camsonne, G D, Cates, Z, Chai, J-P, Chen, Seonho, Choi, E, Chudakov, F, Cusanno, R De, Leo, A, Deur, S, Dieterich, D, Dutta, J M, Finn, S, Frullani, H, Gao, J, Gao, F, Garibaldi, S, Gilad, R, Gilman, J, Gomez, J-O, Hansen, D W, Higinbotham, W, Hinton, T, Horn, C W, De Jager, X, Jiang, L, Kaufman, J, Kelly, W, Korsch, K, Kramer, J, LeRose, D, Lhuillier, N, Liyanage, D J, Margaziotis, F, Marie, P, Markowitz, K, McCormick, Z-E, Meziani, R, Michaels, B, Moffit, S, Nanda, D, Neyret, S K, Phillips, A, Powell, T, Pussieux, B, Reitz, J, Roche, R, Roche, M, Roedelbronn, G, Ron, M, Rvachev, A, Saha, N, Savvinov, J, Singh, S, Sirca, K, Slifer, P, Solvignon, P, Souder, D J, Steiner, S, Strauch, V, Sulkosky, A, Tobias, G, Urciuoli, A, Vacheret, B, Wojtsekhowski, H, Xiang, Y, Xiao, F, Xiong, B, Zhang, L, Zhu, X, Zhu, and P A, Zołnierczuk
Subjects: Nuclear Theory, High Energy Physics::Experiment, Nuclear Experiment
Abstract: We have measured the neutron spin asymmetry A(n)(1) with high precision at three kinematics in the deep inelastic region at x=0.33, 0.47, and 0.60, and Q(2)=2.7, 3.5, and 4.8 (GeV/c)(2), respectively. Our results unambiguously show, for the first time, that A(n)(1) crosses zero around x=0.47 and becomes significantly positive at x=0.60. Combined with the world proton data, polarized quark distributions were extracted. Our results, in general, agree with relativistic constituent quark models and with perturbative quantum chromodynamics (PQCD) analyses based on the earlier data. However they deviate from PQCD predictions based on hadron helicity conservation.
Published: 2004

15. Measurement of the generalized polarizabilities of the proton in virtual Compton scattering at Q2=0.92 and 1.76 GeV2

Author: G, Laveissière, L, Todor, N, Degrande, S, Jaminion, C, Jutier, R, Di Salvo, L, Van Hoorebeke, L C, Alexa, B D, Anderson, K A, Aniol, K, Arundell, G, Audit, L, Auerbach, F T, Baker, M, Baylac, J, Berthot, P Y, Bertin, W, Bertozzi, L, Bimbot, W U, Boeglin, E J, Brash, V, Breton, H, Breuer, E, Burtin, J R, Calarco, L S, Cardman, C, Cavata, C-C, Chang, J-P, Chen, E, Chudakov, E, Cisbani, D S, Dale, C W, de Jager, R, De Leo, A, Deur, N, d'Hose, G E, Dodge, J J, Domingo, L, Elouadrhiri, M B, Epstein, L A, Ewell, J M, Finn, K G, Fissum, H, Fonvieille, G, Fournier, B, Frois, S, Frullani, C, Furget, H, Gao, J, Gao, F, Garibaldi, A, Gasparian, S, Gilad, R, Gilman, A, Glamazdin, C, Glashausser, J, Gomez, V, Gorbenko, P, Grenier, P A M, Guichon, J O, Hansen, R, Holmes, M, Holtrop, C, Howell, G M, Huber, C E, Hyde-Wright, S, Incerti, M, Iodice, J, Jardillier, M K, Jones, W, Kahl, S, Kato, A T, Katramatou, J J, Kelly, S, Kerhoas, A, Ketikyan, M, Khayat, K, Kino, S, Kox, L H, Kramer, K S, Kumar, G, Kumbartzki, M, Kuss, A, Leone, J J, LeRose, M, Liang, R A, Lindgren, N, Liyanage, G J, Lolos, R W, Lourie, R, Madey, K, Maeda, S, Malov, D M, Manley, C, Marchand, D, Marchand, D J, Margaziotis, P, Markowitz, J, Marroncle, J, Martino, K, McCormick, J, McIntyre, S, Mehrabyan, F, Merchez, Z E, Meziani, R, Michaels, G W, Miller, J Y, Mougey, S K, Nanda, D, Neyret, E A J M, Offermann, Z, Papandreou, B, Pasquini, C F, Perdrisat, R, Perrino, G G, Petratos, S, Platchkov, R, Pomatsalyuk, D L, Prout, V A, Punjabi, T, Pussieux, G, Quémenér, R D, Ransome, O, Ravel, J S, Real, F, Renard, Y, Roblin, D, Rowntree, G, Rutledge, P M, Rutt, A, Saha, T, Saito, A J, Sarty, A, Serdarevic, T, Smith, G, Smirnov, K, Soldi, P, Sorokin, P A, Souder, R, Suleiman, J A, Templon, T, Terasawa, R, Tieulent, E, Tomasi-Gustaffson, H, Tsubota, H, Ueno, P E, Ulmer, G M, Urciuoli, M, Vanderhaeghen, R, Van De Vyver, R L J, Van der Meer, P, Vernin, B, Vlahovic, H, Voskanyan, E, Voutier, J W, Watson, L B, Weinstein, K, Wijesooriya, R, Wilson, B B, Wojtsekhowski, D G, Zainea, W-M, Zhang, J, Zhao, and Z-L, Zhou
Abstract: We report a virtual Compton scattering study of the proton at low c.m. energies. We have determined the structure functions P(LL)-P(TT)/epsilon and P(LT), and the electric and magnetic generalized polarizabilities (GPs) alpha(E)(Q2) and beta(M)(Q2) at momentum transfer Q(2)=0.92 and 1.76 GeV2. The electric GP shows a strong falloff with Q2, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a falloff; this can be interpreted as the dominance of a long-distance diamagnetic pion cloud at low Q2, compensated at higher Q2 by a paramagnetic contribution from piN intermediate states.
Published: 2003

16. Measurement of G(E(p))/G(M(p)) in e(--)p---e(--)p to Q(2) = 5.6 GeV(2)

Author: O, Gayou, K A, Aniol, T, Averett, F, Benmokhtar, W, Bertozzi, L, Bimbot, E J, Brash, J R, Calarco, C, Cavata, Z, Chai, C-C, Chang, T, Chang, J-P, Chen, E, Chudakov, R, De Leo, S, Dieterich, R, Endres, M B, Epstein, S, Escoffier, K G, Fissum, H, Fonvieille, S, Frullani, J, Gao, F, Garibaldi, S, Gilad, R, Gilman, A, Glamazdin, C, Glashausser, J, Gomez, V, Gorbenko, J-O, Hansen, D W, Higinbotham, G M, Huber, M, Iodice, C W, de Jager, X, Jiang, M K, Jones, J J, Kelly, M, Khandaker, A, Kozlov, K M, Kramer, G, Kumbartzki, J J, LeRose, D, Lhuillier, R A, Lindgren, N, Liyanage, G J, Lolos, D J, Margaziotis, F, Marie, P, Markowitz, K, McCormick, R, Michaels, B D, Milbrath, S K, Nanda, D, Neyret, Z, Papandreou, L, Pentchev, C F, Perdrisat, N M, Piskunov, V, Punjabi, T, Pussieux, G, Quéméner, R D, Ransome, B A, Raue, R, Roché, M, Rvachev, A, Saha, C, Salgado, S, Sirca, I, Sitnik, S, Strauch, L, Todor, E, Tomasi-Gustafsson, G M, Urciuoli, H, Voskanyan, K, Wijesooriya, B B, Wojtsekhowski, X, Zheng, and L, Zhu
Abstract: The ratio of the electric and magnetic form factors of the proton G(E(p))/G(M(p)), which is an image of its charge and magnetization distributions, was measured at the Thomas Jefferson National Accelerator Facility (JLab) using the recoil polarization technique. The ratio of the form factors is directly proportional to the ratio of the transverse to longitudinal components of the polarization of the recoil proton in the elastic e(--)p---e(--)p reaction. The new data presented span the range 3.5Q(2)5.6 GeV(2) and are well described by a linear Q(2) fit. Also, the ratio sqrt[Q(2)] F(2(p))/F(1(p)) reaches a constant value above Q(2) = 2 GeV(2).
Published: 2001

17. Dynamics of the 16O(e, e'p) reaction at high missing energies

Author: N, Liyanage, B D, Anderson, K A, Aniol, L, Auerbach, F T, Baker, J, Berthot, W, Bertozzi, P Y, Bertin, L, Bimbot, W U, Boeglin, E J, Brash, V, Breton, H, Breuer, E, Burtin, J R, Calarco, L, Cardman, G D, Cates, C, Cavata, C C, Chang, J P, Chen, E, Cisbani, D S, Dale, R, De Leo, A, Deur, B, Diederich, P, Djawotho, J, Domingo, B, Doyle, J E, Ducret, M B, Epstein, L A, Ewell, J M, Finn, K G, Fissum, H, Fonvieille, B, Frois, S, Frullani, J, Gao, F, Garibaldi, A, Gasparian, S, Gilad, R, Gilman, A, Glamazdin, C, Glashausser, J, Gomez, V, Gorbenko, T, Gorringe, F W, Hersman, R, Holmes, M, Holtrop, N, d'Hose, C, Howell, G M, Huber, C E, Hyde-Wright, M, Iodice, C W, de Jager, S, Jaminion, M K, Jones, K, Joo, C, Jutier, W, Kahl, S, Kato, J J, Kelly, S, Kerhoas, M, Khandaker, M, Khayat, K, Kino, W, Korsch, L, Kramer, K S, Kumar, G, Kumbartzki, G, Laveissière, A, Leone, J J, LeRose, L, Levchuk, M, Liang, R A, Lindgren, G J, Lolos, R W, Lourie, R, Madey, K, Maeda, S, Malov, D M, Manley, D J, Margaziotis, P, Markowitz, J, Martino, J S, McCarthy, K, McCormick, J, McIntyre, R L, van der Meer, Z E, Meziani, R, Michaels, J, Mougey, S, Nanda, D, Neyret, E A, Offermann, Z, Papandreou, C F, Perdrisat, R, Perrino, G G, Petratos, S, Platchkov, R, Pomatsalyuk, D L, Prout, V A, Punjabi, T, Pussieux, G, Quéméner, R D, Ransome, O, Ravel, Y, Roblin, R, Roche, D, Rowntree, G A, Rutledge, P M, Rutt, A, Saha, T, Saito, A J, Sarty, A, Serdarevic-Offermann, T P, Smith, A, Soldi, P, Sorokin, P, Souder, R, Suleiman, J A, Templon, T, Terasawa, L, Todor, H, Tsubota, H, Ueno, P E, Ulmer, G M, Urciuoli, P, Vernin, S, van Verst, B, Vlahovic, H, Voskanyan, J W, Watson, L B, Weinstein, K, Wijesooriya, R, Wilson, B, Wojtsekhowski, D G, Zainea, V, Zeps, J, Zhao, and Z L, Zhou
Abstract: We measured the cross section and response functions for the quasielastic 16O(e,e'p) reaction for missing energies 25or =E(m)or =120 MeV at missing momenta P(m)or =340 MeV/c. For 25E(m)50 MeV and P(m) approximately 60 MeV/c, the reaction is dominated by a single 1s(1/2) proton knockout. At larger P(m), the single-particle aspects are increasingly masked by more complicated processes. Calculations which include pion exchange currents, isobar currents, and short-range correlations account for the shape and the transversity, but for only half of the magnitude of the measured cross section.
Published: 2000

18. Novel Measurement of the Neutron Magnetic Form Factor from A=3 Mirror Nuclei.

Author: Santiesteban SN, Li S, Abrams D, Alsalmi S, Androic D, Aniol K, Arrington J, Averett T, Ayerbe Gayoso C, Bane J, Barcus S, Barrow J, Beck A, Bellini V, Bhatt H, Bhetuwal D, Biswas D, Camsonne A, Castellanos J, Chen J, Chen JP, Chrisman D, Christy ME, Clarke C, Covrig S, Cruz-Torres R, Day D, Dutta D, Fuchey E, Gal C, Garibaldi F, Gautam TN, Gogami T, Gomez J, Guèye P, Hague TJ, Hansen JO, Hauenstein F, Henry W, Higinbotham DW, Holt RJ, Hyde C, Itabashi K, Kaneta M, Karki A, Katramatou AT, Keppel CE, King PM, Kurbany L, Kutz T, Lashley-Colthirst N, Li WB, Liu H, Liyanage N, Long E, Lovato A, Mammei J, Markowitz P, McClellan RE, Meddi F, Meekins D, Michaels R, Mihovilovič M, Moyer A, Nagao S, Nguyen D, Nycz M, Olson M, Ou L, Owen V, Palatchi C, Pandey B, Papadopoulou A, Park S, Petkovic T, Premathilake S, Punjabi V, Ransome RD, Reimer PE, Reinhold J, Riordan S, Rocco N, Rodriguez VM, Schmidt A, Schmookler B, Segarra EP, Shahinyan A, Širca S, Slifer K, Solvignon P, Su T, Suleiman R, Tang L, Tian Y, Tireman W, Tortorici F, Toyama Y, Uehara K, Urciuoli GM, Votaw D, Williamson J, Wojtsekhowski B, Wood S, Ye ZH, Zhang J, and Zheng X
Abstract: The electromagnetic form factors of the proton and neutron encode information on the spatial structure of their charge and magnetization distributions. While measurements of the proton are relatively straightforward, the lack of a free neutron target makes measurements of the neutron's electromagnetic structure more challenging and more sensitive to experimental or model-dependent uncertainties. Various experiments have attempted to extract the neutron form factors from scattering from the neutron in deuterium, with different techniques providing different, and sometimes large, systematic uncertainties. We present results from a novel measurement of the neutron magnetic form factor using quasielastic scattering from the mirror nuclei ^{3}H and ^{3}He, where the nuclear effects are larger than for deuterium but expected to largely cancel in the cross-section ratios. We extracted values of the neutron magnetic form factor for low-to-modest momentum transfer, 0.6
Published: 2024
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19. Precision Determination of the Neutral Weak Form Factor of ^{48}Ca.

Author: Adhikari D, Albataineh H, Androic D, Aniol KA, Armstrong DS, Averett T, Ayerbe Gayoso C, Barcus SK, Bellini V, Beminiwattha RS, Benesch JF, Bhatt H, Bhatta Pathak D, Bhetuwal D, Blaikie B, Boyd J, Campagna Q, Camsonne A, Cates GD, Chen Y, Clarke C, Cornejo JC, Covrig Dusa S, Dalton MM, Datta P, Deshpande A, Dutta D, Feldman C, Fuchey E, Gal C, Gaskell D, Gautam T, Gericke M, Ghosh C, Halilovic I, Hansen JO, Hassan O, Hauenstein F, Henry W, Horowitz CJ, Jantzi C, Jian S, Johnston S, Jones DC, Kakkar S, Katugampola S, Keppel C, King PM, King DE, Kumar KS, Kutz T, Lashley-Colthirst N, Leverick G, Liu H, Liyanage N, Mammei J, Mammei R, McCaughan M, McNulty D, Meekins D, Metts C, Michaels R, Mihovilovic M, Mondal MM, Napolitano J, Narayan A, Nikolaev D, Owen V, Palatchi C, Pan J, Pandey B, Park S, Paschke KD, Petrusky M, Pitt ML, Premathilake S, Quinn B, Radloff R, Rahman S, Rashad MNH, Rathnayake A, Reed BT, Reimer PE, Richards R, Riordan S, Roblin YR, Seeds S, Shahinyan A, Souder P, Thiel M, Tian Y, Urciuoli GM, Wertz EW, Wojtsekhowski B, Yale B, Ye T, Yoon A, Xiong W, Zec A, Zhang W, Zhang J, and Zheng X
Abstract: We report a precise measurement of the parity-violating (PV) asymmetry A_{PV} in the elastic scattering of longitudinally polarized electrons from ^{48}Ca. We measure A_{PV}=2668±106(stat)±40(syst) parts per billion, leading to an extraction of the neutral weak form factor F_{W}(q=0.8733 fm^{-1})=0.1304±0.0052(stat)±0.0020(syst) and the charge minus the weak form factor F_{ch}-F_{W}=0.0277±0.0055. The resulting neutron skin thickness R_{n}-R_{p}=0.121±0.026(exp)±0.024(model) fm is relatively thin yet consistent with many model calculations. The combined CREX and PREX results will have implications for future energy density functional calculations and on the density dependence of the symmetry energy of nuclear matter.
Published: 2022
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20. Measurement of the Nucleon F_{2}^{n}/F_{2}^{p} Structure Function Ratio by the Jefferson Lab MARATHON Tritium/Helium-3 Deep Inelastic Scattering Experiment.

Author: Abrams D, Albataineh H, Aljawrneh BS, Alsalmi S, Androic D, Aniol K, Armstrong W, Arrington J, Atac H, Averett T, Gayoso CA, Bai X, Bane J, Barcus S, Beck A, Bellini V, Bhatt H, Bhetuwal D, Biswas D, Blyth D, Boeglin W, Bulumulla D, Butler J, Camsonne A, Carmignotto M, Castellanos J, Chen JP, Cohen EO, Covrig S, Craycraft K, Cruz-Torres R, Dongwi B, Duran B, Dutta D, Fuchey E, Gal C, Gautam TN, Gilad S, Gnanvo K, Gogami T, Gomez J, Gu C, Habarakada A, Hague T, Hansen JO, Hattawy M, Hauenstein F, Higinbotham DW, Holt RJ, Hughes EW, Hyde C, Ibrahim H, Jian S, Joosten S, Karki A, Karki B, Katramatou AT, Keith C, Keppel C, Khachatryan M, Khachatryan V, Khanal A, Kievsky A, King D, King PM, Korover I, Kulagin SA, Kumar KS, Kutz T, Lashley-Colthirst N, Li S, Li W, Liu H, Liuti S, Liyanage N, Markowitz P, McClellan RE, Meekins D, Beck SM, Meziani ZE, Michaels R, Mihovilovic M, Nelyubin V, Nguyen D, Nuruzzaman, Nycz M, Obrecht R, Olson M, Owen VF, Pace E, Pandey B, Pandey V, Paolone M, Papadopoulou A, Park S, Paul S, Petratos GG, Petti R, Piasetzky E, Pomatsalyuk R, Premathilake S, Puckett AJR, Punjabi V, Ransome RD, Rashad MNH, Reimer PE, Riordan S, Roche J, Salmè G, Santiesteban N, Sawatzky B, Scopetta S, Schmidt A, Schmookler B, Segal J, Segarra EP, Shahinyan A, Širca S, Sparveris N, Su T, Suleiman R, Szumila-Vance H, Tadepalli AS, Tang L, Tireman W, Tortorici F, Urciuoli GM, Wojtsekhowski B, Wood S, Ye ZH, Ye ZY, and Zhang J
Abstract: The ratio of the nucleon F_{2} structure functions, F_{2}^{n}/F_{2}^{p}, is determined by the MARATHON experiment from measurements of deep inelastic scattering of electrons from ^{3}H and ^{3}He nuclei. The experiment was performed in the Hall A Facility of Jefferson Lab using two high-resolution spectrometers for electron detection, and a cryogenic target system which included a low-activity tritium cell. The data analysis used a novel technique exploiting the mirror symmetry of the two nuclei, which essentially eliminates many theoretical uncertainties in the extraction of the ratio. The results, which cover the Bjorken scaling variable range 0.19
Published: 2022
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21. Probing Few-Body Nuclear Dynamics via ^{3}H and ^{3}He (e,e^{'}p)pn Cross-Section Measurements.

Author: Cruz-Torres R, Nguyen D, Hauenstein F, Schmidt A, Li S, Abrams D, Albataineh H, Alsalmi S, Androic D, Aniol K, Armstrong W, Arrington J, Atac H, Averett T, Ayerbe Gayoso C, Bai X, Bane J, Barcus S, Beck A, Bellini V, Benmokhtar F, Bhatt H, Bhetuwal D, Biswas D, Blyth D, Boeglin W, Bulumulla D, Camsonne A, Castellanos J, Chen JP, Cohen EO, Covrig S, Craycraft K, Dongwi B, Duer M, Duran B, Dutta D, Fuchey E, Gal C, Gautam TN, Gilad S, Gnanvo K, Gogami T, Golak J, Gomez J, Gu C, Habarakada A, Hague T, Hansen O, Hattawy M, Hen O, Higinbotham DW, Hughes E, Hyde C, Ibrahim H, Jian S, Joosten S, Kamada H, Karki A, Karki B, Katramatou AT, Keppel C, Khachatryan M, Khachatryan V, Khanal A, King D, King P, Korover I, Kutz T, Lashley-Colthirst N, Laskaris G, Li W, Liu H, Liyanage N, Markowitz P, McClellan RE, Meekins D, Mey-Tal Beck S, Meziani ZE, Michaels R, Mihovilovič M, Nelyubin V, Nuruzzaman N, Nycz M, Obrecht R, Olson M, Ou L, Owen V, Pandey B, Pandey V, Papadopoulou A, Park S, Patsyuk M, Paul S, Petratos GG, Piasetzky E, Pomatsalyuk R, Premathilake S, Puckett AJR, Punjabi V, Ransome R, Rashad MNH, Reimer PE, Riordan S, Roche J, Sargsian M, Santiesteban N, Sawatzky B, Segarra EP, Schmookler B, Shahinyan A, Širca S, Skibiński R, Sparveris N, Su T, Suleiman R, Szumila-Vance H, Tadepalli AS, Tang L, Tireman W, Topolnicki K, Tortorici F, Urciuoli G, Weinstein LB, Witała H, Wojtsekhowski B, Wood S, Ye ZH, Ye ZY, and Zhang J
Abstract: We report the first measurement of the (e,e^{'}p) three-body breakup reaction cross sections in helium-3 (^{3}He) and tritium (^{3}H) at large momentum transfer [⟨Q^{2}⟩≈1.9 (GeV/c)^{2}] and x_{B}>1 kinematics, where the cross section should be sensitive to quasielastic (QE) scattering from single nucleons. The data cover missing momenta 40≤p_{miss}≤500 MeV/c that, in the QE limit with no rescattering, equals the initial momentum of the probed nucleon. The measured cross sections are compared with state-of-the-art ab initio calculations. Overall good agreement, within ±20%, is observed between data and calculations for the full p_{miss} range for ^{3}H and for 100≤p_{miss}≤350 MeV/c for ^{3}He. Including the effects of rescattering of the outgoing nucleon improves agreement with the data at p_{miss}>250 MeV/c and suggests contributions from charge-exchange (SCX) rescattering. The isoscalar sum of ^{3}He plus ^{3}H, which is largely insensitive to SCX, is described by calculations to within the accuracy of the data over the entire p_{miss} range. This validates current models of the ground state of the three-nucleon system up to very high initial nucleon momenta of 500 MeV/c.
Published: 2020
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22. Revealing Color Forces with Transverse Polarized Electron Scattering.

Author: Armstrong W, Kang H, Liyanage A, Maxwell J, Mulholland J, Ndukum L, Ahmidouch A, Albayrak I, Asaturyan A, Ates O, Baghdasaryan H, Boeglin W, Bosted P, Brash E, Butuceanu C, Bychkov M, Carter P, Chen C, Chen JP, Choi S, Christy ME, Covrig S, Crabb D, Danagoulian S, Daniel A, Davidenko AM, Davis B, Day D, Deconinck W, Deur A, Dunne J, Dutta D, El Fassi L, Ellis C, Ent R, Flay D, Frlez E, Gaskell D, Geagla O, German J, Gilman R, Gogami T, Gomez J, Goncharenko YM, Hashimoto O, Higinbotham D, Horn T, Huber GM, Jones M, Jones MK, Kalantarians N, Kang HK, Kawama D, Keith C, Keppel C, Khandaker M, Kim Y, King PM, Kohl M, Kovacs K, Kubarovsky V, Li Y, Liyanage N, Luo W, Mack D, Mamyan V, Markowitz P, Maruta T, Meekins D, Melnik YM, Meziani ZE, Mkrtchyan A, Mkrtchyan H, Mochalov VV, Monaghan P, Narayan A, Nakamura SN, Nuruzzaman A, Pentchev L, Pocanic D, Posik M, Puckett A, Qiu X, Reinhold J, Riordan S, Roche J, Rondón OA, Sawatzky B, Shabestari M, Slifer K, Smith G, Soloviev LF, Solvignon P, Tadevosyan V, Tang L, Vasiliev AN, Veilleux M, Walton T, Wesselmann F, Wood S, Yao H, Ye Z, Zhang J, and Zhu L
Abstract: The Spin Asymmetries of the Nucleon Experiment measured two double spin asymmetries using a polarized proton target and polarized electron beam at two beam energies, 4.7 and 5.9 GeV. A large-acceptance open-configuration detector package identified scattered electrons at 40° and covered a wide range in Bjorken x (0.3
Published: 2019
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23. Precision Measurement of the p(e,e^{'}p)π^{0} Reaction at Threshold.

Author: Chirapatpimol K, Shabestari MH, Lindgren RA, Smith LC, Annand JR, Higinbotham DW, Moffit B, Nelyubin V, Norum BE, Allada K, Aniol K, Ardashev K, Armstrong DS, Arndt RA, Benmokhtar F, Bernstein AM, Bertozzi W, Briscoe WJ, Bimbot L, Camsonne A, Chen JP, Choi S, Chudakov E, Cisbani E, Cusanno F, Dalton MM, Dutta C, Egiyan K, Fernàndez-Ramìrez C, Feuerbach R, Fissum KG, Frullani S, Garibaldi F, Gayou O, Gilman R, Gilad S, Goity J, Gomez J, Hahn B, Hamilton D, Hansen JO, Huang J, Igarashi R, Ireland D, de Jager CW, Jin X, Jiang X, Jinasundera T, Kellie J, Keppel CE, Kolb N, LeRose J, Liyanage N, Livingston K, McNulty D, Mercado L, Michaels R, Mihovilovič M, Qian S, Qian X, Mailyan S, Mamyan V, Marrone S, Monaghan P, Nanda S, Perdrisat CF, Piasetzky E, Protopopescu D, Punjabi V, Qiang Y, Rachek IA, Rakhman A, Riordan S, Ron G, Rosner G, Saha A, Sawatzky B, Shahinyan A, Širca S, Sparveris N, Subedi RR, Suleiman R, Strakovsky I, Sulkosky V, Moinelo J, Voskanyan H, Wang K, Wang Y, Watson J, Watts D, Wojtsekhowski B, Workman RL, Yao H, Zhan X, and Zhang Y
Abstract: New results are reported from a measurement of π^{0} electroproduction near threshold using the p(e,e^{'}p)π^{0} reaction. The experiment was designed to determine precisely the energy dependence of s- and p-wave electromagnetic multipoles as a stringent test of the predictions of chiral perturbation theory (ChPT). The data were taken with an electron beam energy of 1192 MeV using a two-spectrometer setup in Hall A at Jefferson Lab. For the first time, complete coverage of the ϕ_{π}^{*} and θ_{π}^{*} angles in the pπ^{0} center of mass was obtained for invariant energies above threshold from 0.5 up to 15 MeV. The 4-momentum transfer Q^{2} coverage ranges from 0.05 to 0.155 (GeV/c)^{2} in fine steps. A simple phenomenological analysis of our data shows strong disagreement with p-wave predictions from ChPT for Q^{2}>0.07 (GeV/c)^{2}, while the s-wave predictions are in reasonable agreement.
Published: 2015
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24. Precision measurement of the neutron twist-3 matrix element d(2)(n): probing color forces.

Author: Posik M, Flay D, Parno DS, Allada K, Armstrong W, Averett T, Benmokhtar F, Bertozzi W, Camsonne A, Canan M, Cates GD, Chen C, Chen JP, Choi S, Chudakov E, Cusanno F, Dalton MM, Deconinck W, de Jager CW, Deng X, Deur A, Dutta C, El Fassi L, Franklin GB, Friend M, Gao H, Garibaldi F, Gilad S, Gilman R, Glamazdin O, Golge S, Gomez J, Guo L, Hansen O, Higinbotham DW, Holmstrom T, Huang J, Hyde C, Ibrahim HF, Jiang X, Jin G, Katich J, Kelleher A, Kolarkar A, Korsch W, Kumbartzki G, LeRose JJ, Lindgren R, Liyanage N, Long E, Lukhanin A, Mamyan V, McNulty D, Meziani ZE, Michaels R, Mihovilovič M, Moffit B, Muangma N, Nanda S, Narayan A, Nelyubin V, Norum B, Nuruzzaman, Oh Y, Peng JC, Qian X, Qiang Y, Rakhman A, Riordan S, Saha A, Sawatzky B, Shabestari MH, Shahinyan A, Širca S, Solvignon P, Subedi R, Sulkosky V, Tobias WA, Troth W, Wang D, Wang Y, Wojtsekhowski B, Yan X, Yao H, Ye Y, Ye Z, Yuan L, Zhan X, Zhang Y, Zhang YW, Zhao B, and Zheng X
Abstract: Double-spin asymmetries and absolute cross sections were measured at large Bjorken x (0.25≤x≤0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized (3)He target. In this dedicated experiment, the spin structure function g(2)((3)He) was determined with precision at large x, and the neutron twist-3 matrix element d(2)(n) was measured at ⟨Q(2)⟩ of 3.21 and 4.32 GeV(2)/c(2), with an absolute precision of about 10(-5). Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at ⟨Q(2)⟩=5 GeV(2)/c(2). Combining d(2)(n) and a newly extracted twist-4 matrix element f(2)(n), the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 30 MeV/fm in magnitude.
Published: 2014
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25. Measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the reaction (3)He(↑)(e,e')X.

Author: Katich J, Qian X, Zhao YX, Allada K, Aniol K, Annand JR, Averett T, Benmokhtar F, Bertozzi W, Bradshaw PC, Bosted P, Camsonne A, Canan M, Cates GD, Chen C, Chen JP, Chen W, Chirapatpimol K, Chudakov E, Cisbani E, Cornejo JC, Cusanno F, Dalton MM, Deconinck W, de Jager CW, De Leo R, Deng X, Deur A, Ding H, Dolph PA, Dutta C, Dutta D, El Fassi L, Frullani S, Gao H, Garibaldi F, Gaskell D, Gilad S, Gilman R, Glamazdin O, Golge S, Guo L, Hamilton D, Hansen O, Higinbotham DW, Holmstrom T, Huang J, Huang M, Ibrahim HF, Iodice M, Jiang X, Jin G, Jones MK, Kelleher A, Kim W, Kolarkar A, Korsch W, LeRose JJ, Li X, Li Y, Lindgren R, Liyanage N, Long E, Lu HJ, Margaziotis DJ, Markowitz P, Marrone S, McNulty D, Meziani ZE, Michaels R, Moffit B, Muñoz Camacho C, Nanda S, Narayan A, Nelyubin V, Norum B, Oh Y, Osipenko M, Parno D, Peng JC, Phillips SK, Posik M, Puckett AJ, Qiang Y, Rakhman A, Ransome RD, Riordan S, Saha A, Sawatzky B, Schulte E, Shahinyan A, Shabestari MH, Širca S, Stepanyan S, Subedi R, Sulkosky V, Tang LG, Tobias A, Urciuoli GM, Vilardi I, Wang K, Wang Y, Wojtsekhowski B, Yan X, Yao H, Ye Y, Ye Z, Yuan L, Zhan X, Zhang Y, Zhang YW, Zhao B, Zheng X, Zhu L, Zhu X, and Zong X
Abstract: We report the first measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the inclusive reaction 3)He(↑)(e,e')X on a polarized (3)He gas target. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation but can be nonzero if two-photon-exchange contributions are included. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.72 GeV, which is nonzero at the 2.89σ level. Our measured asymmetry agrees both in sign and magnitude with a two-photon-exchange model prediction that uses input from the Sivers transverse momentum distribution obtained from semi-inclusive deep-inelastic scattering.
Published: 2014
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26. Measurements of parity-violating asymmetries in electron-deuteron scattering in the nucleon resonance region.

Author: Wang D, Pan K, Subedi R, Deng X, Ahmed Z, Allada K, Aniol KA, Armstrong DS, Arrington J, Bellini V, Beminiwattha R, Benesch J, Benmokhtar F, Camsonne A, Canan M, Cates GD, Chen JP, Chudakov E, Cisbani E, Dalton MM, de Jager CW, De Leo R, Deconinck W, Deur A, Dutta C, El Fassi L, Flay D, Franklin GB, Friend M, Frullani S, Garibaldi F, Giusa A, Glamazdin A, Golge S, Grimm K, Hafidi K, Hansen O, Higinbotham DW, Holmes R, Holmstrom T, Holt RJ, Huang J, Hyde CE, Jen CM, Jones D, Kang H, King P, Kowalski S, Kumar KS, Lee JH, LeRose JJ, Liyanage N, Long E, McNulty D, Margaziotis DJ, Meddi F, Meekins DG, Mercado L, Meziani ZE, Michaels R, Mihovilovic M, Muangma N, Myers KE, Nanda S, Narayan A, Nelyubin V, Nuruzzaman, Oh Y, Parno D, Paschke KD, Phillips SK, Qian X, Qiang Y, Quinn B, Rakhman A, Reimer PE, Rider K, Riordan S, Roche J, Rubin J, Russo G, Saenboonruang K, Saha A, Sawatzky B, Shahinyan A, Silwal R, Sirca S, Souder PA, Suleiman R, Sulkosky V, Sutera CM, Tobias WA, Urciuoli GM, Waidyawansa B, Wojtsekhowski B, Ye L, Zhao B, and Zheng X
Abstract: We report on parity-violating asymmetries in the nucleon resonance region measured using inclusive inelastic scattering of 5-6 GeV longitudinally polarized electrons off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the Δ(1232). They provide a verification of quark-hadron duality-the equivalence of the quark- and hadron-based pictures of the nucleon-at the (10-15)% level in this electroweak observable, which is dominated by contributions from the nucleon electroweak γZ interference structure functions. In addition, the results provide constraints on nucleon resonance models relevant for calculating background corrections to elastic parity-violating electron scattering measurements.
Published: 2013
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27. Measurement of the neutron radius of 208Pb through parity violation in electron scattering.

Author: Abrahamyan S, Ahmed Z, Albataineh H, Aniol K, Armstrong DS, Armstrong W, Averett T, Babineau B, Barbieri A, Bellini V, Beminiwattha R, Benesch J, Benmokhtar F, Bielarski T, Boeglin W, Camsonne A, Canan M, Carter P, Cates GD, Chen C, Chen JP, Hen O, Cusanno F, Dalton MM, De Leo R, de Jager K, Deconinck W, Decowski P, Deng X, Deur A, Dutta D, Etile A, Flay D, Franklin GB, Friend M, Frullani S, Fuchey E, Garibaldi F, Gasser E, Gilman R, Giusa A, Glamazdin A, Gomez J, Grames J, Gu C, Hansen O, Hansknecht J, Higinbotham DW, Holmes RS, Holmstrom T, Horowitz CJ, Hoskins J, Huang J, Hyde CE, Itard F, Jen CM, Jensen E, Jin G, Johnston S, Kelleher A, Kliakhandler K, King PM, Kowalski S, Kumar KS, Leacock J, Leckey J 4th, Lee JH, LeRose JJ, Lindgren R, Liyanage N, Lubinsky N, Mammei J, Mammoliti F, Margaziotis DJ, Markowitz P, McCreary A, McNulty D, Mercado L, Meziani ZE, Michaels RW, Mihovilovic M, Muangma N, Muñoz-Camacho C, Nanda S, Nelyubin V, Nuruzzaman N, Oh Y, Palmer A, Parno D, Paschke KD, Phillips SK, Poelker B, Pomatsalyuk R, Posik M, Puckett AJ, Quinn B, Rakhman A, Reimer PE, Riordan S, Rogan P, Ron G, Russo G, Saenboonruang K, Saha A, Sawatzky B, Shahinyan A, Silwal R, Sirca S, Slifer K, Solvignon P, Souder PA, Sperduto ML, Subedi R, Suleiman R, Sulkosky V, Sutera CM, Tobias WA, Troth W, Urciuoli GM, Waidyawansa B, Wang D, Wexler J, Wilson R, Wojtsekhowski B, Yan X, Yao H, Ye Y, Ye Z, Yim V, Zana L, Zhan X, Zhang J, Zhang Y, Zheng X, and Zhu P
Abstract: We report the first measurement of the parity-violating asymmetry A(PV) in the elastic scattering of polarized electrons from 208Pb. A(PV) is sensitive to the radius of the neutron distribution (R(n)). The result A(PV)=0.656±0.060(stat)±0.014(syst) ppm corresponds to a difference between the radii of the neutron and proton distributions R(n)-R(p)=0.33(-0.18)(+0.16) fm and provides the first electroweak observation of the neutron skin which is expected in a heavy, neutron-rich nucleus.
Published: 2012
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28. New precision limit on the strange vector form factors of the proton.

Author: Ahmed Z, Allada K, Aniol KA, Armstrong DS, Arrington J, Baturin P, Bellini V, Benesch J, Beminiwattha R, Benmokhtar F, Canan M, Camsonne A, Cates GD, Chen JP, Chudakov E, Cisbani E, Dalton MM, de Jager CW, De Leo R, Deconinck W, Decowski P, Deng X, Deur A, Dutta C, Franklin GB, Friend M, Frullani S, Garibaldi F, Giusa A, Glamazdin A, Golge S, Grimm K, Hansen O, Higinbotham DW, Holmes R, Holmstrom T, Huang J, Huang M, Hyde CE, Jen CM, Jin G, Jones D, Kang H, King P, Kowalski S, Kumar KS, Lee JH, LeRose JJ, Liyanage N, Long E, McNulty D, Margaziotis D, Meddi F, Meekins DG, Mercado L, Meziani ZE, Michaels R, Muñoz-Camacho C, Mihovilovic M, Muangma N, Myers KE, Nanda S, Narayan A, Nelyubin V, Nuruzzaman, Oh Y, Pan K, Parno D, Paschke KD, Phillips SK, Qian X, Qiang Y, Quinn B, Rakhman A, Reimer PE, Rider K, Riordan S, Roche J, Rubin J, Russo G, Saenboonruang K, Saha A, Sawatzky B, Silwal R, Sirca S, Souder PA, Sperduto M, Subedi R, Suleiman R, Sulkosky V, Sutera CM, Tobias WA, Urciuoli GM, Waidyawansa B, Wang D, Wexler J, Wilson R, Wojtsekhowski B, Zhan X, Yan X, Yao H, Ye L, Zhao B, and Zheng X
Abstract: The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624 GeV2 and beam energy E(b) = 3.48 GeV to be A(PV) = -23.80 ± 0.78(stat) ± 0.36(syst) parts per million. This result is consistent with zero contribution of strange quarks to the combination of electric and magnetic form factors G(E)(s) + 0.517G(M)(s) = 0.003 ± 0.010(stat) ± 0.004(syst) ± 0.009(ff), where the third error is due to the limits of precision on the electromagnetic form factors and radiative corrections. With this measurement, the world data on strange contributions to nucleon form factors are seen to be consistent with zero and not more than a few percent of the proton form factors.
Published: 2012
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29. Beam-target double-spin asymmetry A{LT} in charged pion production from deep inelastic scattering on a transversely polarized {3}He target at 1.4<Q{2}<2.7 GeV{2}.

Author: Huang J, Allada K, Dutta C, Katich J, Qian X, Wang Y, Zhang Y, Aniol K, Annand JR, Averett T, Benmokhtar F, Bertozzi W, Bradshaw PC, Bosted P, Camsonne A, Canan M, Cates GD, Chen C, Chen JP, Chen W, Chirapatpimol K, Chudakov E, Cisbani E, Cornejo JC, Cusanno F, Dalton MM, Deconinck W, de Jager CW, De Leo R, Deng X, Deur A, Ding H, Dolph PA, Dutta D, El Fassi L, Frullani S, Gao H, Garibaldi F, Gaskell D, Gilad S, Gilman R, Glamazdin O, Golge S, Guo L, Hamilton D, Hansen O, Higinbotham DW, Holmstrom T, Huang M, Ibrahim HF, Iodice M, Jiang X, Jin G, Jones MK, Kelleher A, Kim W, Kolarkar A, Korsch W, Lerose JJ, Li X, Li Y, Lindgren R, Liyanage N, Long E, Lu HJ, Margaziotis DJ, Markowitz P, Marrone S, McNulty D, Meziani ZE, Michaels R, Moffit B, Muñoz Camacho C, Nanda S, Narayan A, Nelyubin V, Norum B, Oh Y, Osipenko M, Parno D, Peng JC, Phillips SK, Posik M, Puckett AJ, Qiang Y, Rakhman A, Ransome RD, Riordan S, Saha A, Sawatzky B, Schulte E, Shahinyan A, Shabestari MH, Sirca S, Stepanyan S, Subedi R, Sulkosky V, Tang LG, Tobias A, Urciuoli GM, Vilardi I, Wang K, Wojtsekhowski B, Yan X, Yao H, Ye Y, Ye Z, Yuan L, Zhan X, Zhang YW, Zhao B, Zheng X, Zhu L, Zhu X, and Zong X
Abstract: We report the first measurement of the double-spin asymmetry A{LT} for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized {3}He target. The kinematics focused on the valence quark region, 0.16
Published: 2012
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30. Search for a new gauge boson in electron-nucleus fixed-target scattering by the APEX experiment.

Author: Abrahamyan S, Ahmed Z, Allada K, Anez D, Averett T, Barbieri A, Bartlett K, Beacham J, Bono J, Boyce JR, Brindza P, Camsonne A, Cranmer K, Dalton MM, de Jager CW, Donaghy J, Essig R, Field C, Folts E, Gasparian A, Goeckner-Wald N, Gomez J, Graham M, Hansen JO, Higinbotham DW, Holmstrom T, Huang J, Iqbal S, Jaros J, Jensen E, Kelleher A, Khandaker M, LeRose JJ, Lindgren R, Liyanage N, Long E, Mammei J, Markowitz P, Maruyama T, Maxwell V, Mayilyan S, McDonald J, Michaels R, Moffeit K, Nelyubin V, Odian A, Oriunno M, Partridge R, Paolone M, Piasetzky E, Pomerantz I, Qiang Y, Riordan S, Roblin Y, Sawatzky B, Schuster P, Segal J, Selvy L, Shahinyan A, Subedi R, Sulkosky V, Stepanyan S, Toro N, Walz D, Wojtsekhowski B, and Zhang J
Abstract: We present a search at the Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling α' to electrons. Such a particle A' can be produced in electron-nucleus fixed-target scattering and then decay to an e + e- pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175-250 MeV, found no evidence for an A'→ e+ e- reaction, and set an upper limit of α'/α ~/= 10(-6). Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.
Published: 2011
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31. Single spin asymmetries in charged pion production from semi-inclusive deep inelastic scattering on a transversely polarized 3He Target at Q2 = 1.4-2.7 GeV2.

Author: Qian X, Allada K, Dutta C, Huang J, Katich J, Wang Y, Zhang Y, Aniol K, Annand JR, Averett T, Benmokhtar F, Bertozzi W, Bradshaw PC, Bosted P, Camsonne A, Canan M, Cates GD, Chen C, Chen JP, Chen W, Chirapatpimol K, Chudakov E, Cisbani E, Cornejo JC, Cusanno F, Dalton MM, Deconinck W, de Jager CW, De Leo R, Deng X, Deur A, Ding H, Dolph PA, Dutta D, El Fassi L, Frullani S, Gao H, Garibaldi F, Gaskell D, Gilad S, Gilman R, Glamazdin O, Golge S, Guo L, Hamilton D, Hansen O, Higinbotham DW, Holmstrom T, Huang M, Ibrahim HF, Iodice M, Jiang X, Jin G, Jones MK, Kelleher A, Kim W, Kolarkar A, Korsch W, LeRose JJ, Li X, Li Y, Lindgren R, Liyanage N, Long E, Lu HJ, Margaziotis DJ, Markowitz P, Marrone S, McNulty D, Meziani ZE, Michaels R, Moffit B, Camacho CM, Nanda S, Narayan A, Nelyubin V, Norum B, Oh Y, Osipenko M, Parno D, Peng JC, Phillips SK, Posik M, Puckett AJ, Qiang Y, Rakhman A, Ransome RD, Riordan S, Saha A, Sawatzky B, Schulte E, Shahinyan A, Shabestari MH, Sirca S, Stepanyan S, Subedi R, Sulkosky V, Tang LG, Tobias A, Urciuoli GM, Vilardi I, Wang K, Wojtsekhowski B, Yan X, Yao H, Ye Y, Ye Z, Yuan L, Zhan X, Zhang YW, Zhao B, Zheng X, Zhu L, Zhu X, and Zong X
Abstract: We report the first measurement of target single spin asymmetries in the semi-inclusive (3)He(e,e'π(±))X reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.16 < x < 0.35 with 1.4 < Q(2) < 2.7 GeV(2). The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The π(±) Collins moments for (3)He are consistent with zero, except for the π(+) moment at x = 0.35, which deviates from zero by 2.3σ. While the π(-) Sivers moments are consistent with zero, the π(+) Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and measured cross section ratios of proton to (3)He, and are largely consistent with the predictions of phenomenological fits and quark model calculations.
Published: 2011
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32. Measurements of the electric form factor of the neutron up to Q2=3.4 GeV2 using the reaction 3He(e,e'n)pp.

Author: Riordan S, Abrahamyan S, Craver B, Kelleher A, Kolarkar A, Miller J, Cates GD, Liyanage N, Wojtsekhowski B, Acha A, Allada K, Anderson B, Aniol KA, Annand JR, Arrington J, Averett T, Beck A, Bellis M, Boeglin W, Breuer H, Calarco JR, Camsonne A, Chen JP, Chudakov E, Coman L, Crowe B, Cusanno F, Day D, Degtyarenko P, Dolph PA, Dutta C, Ferdi C, Fernández-Ramírez C, Feuerbach R, Fraile LM, Franklin G, Frullani S, Fuchs S, Garibaldi F, Gevorgyan N, Gilman R, Glamazdin A, Gomez J, Grimm K, Hansen JO, Herraiz JL, Higinbotham DW, Holmes R, Holmstrom T, Howell D, de Jager CW, Jiang X, Jones MK, Katich J, Kaufman LJ, Khandaker M, Kelly JJ, Kiselev D, Korsch W, LeRose J, Lindgren R, Markowitz P, Margaziotis DJ, Beck SM, Mayilyan S, McCormick K, Meziani ZE, Michaels R, Moffit B, Nanda S, Nelyubin V, Ngo T, Nikolenko DM, Norum B, Pentchev L, Perdrisat CF, Piasetzky E, Pomatsalyuk R, Protopopescu D, Puckett AJ, Punjabi VA, Qian X, Qiang Y, Quinn B, Rachek I, Ransome RD, Reimer PE, Reitz B, Roche J, Ron G, Rondon O, Rosner G, Saha A, Sargsian MM, Sawatzky B, Segal J, Shabestari M, Shahinyan A, Shestakov Y, Singh J, Sirca S, Souder P, Stepanyan S, Stibunov V, Sulkosky V, Tajima S, Tobias WA, Udias JM, Urciuoli GM, Vlahovic B, Voskanyan H, Wang K, Wesselmann FR, Vignote JR, Wood SA, Wright J, Yao H, and Zhu X
Abstract: The electric form factor of the neutron was determined from studies of the reaction 3He(e,e'n)pp in quasielastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear polarization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. More than doubling the Q2 range over which it is known, we find G(E)(n)=0.0236±0.0017(stat)±0.0026(syst), 0.0208±0.0024±0.0019, and 0.0147±0.0020±0.0014 for Q(2)=1.72, 2.48, and 3.41 GeV2, respectively.
Published: 2010
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33. Quark-hadron duality in neutron (3He) spin structure.

Author: Solvignon P, Liyanage N, Chen JP, Choi S, Aniol K, Averett T, Boeglin W, Camsonne A, Cates GD, Chang CC, Chudakov E, Craver B, Cusanno F, Deur A, Dutta D, Ent R, Feuerbach R, Frullani S, Gao H, Garibaldi F, Gilman R, Glashausser C, Gorbenko V, Hansen O, Higinbotham DW, Ibrahim H, Jiang X, Jones M, Kelleher A, Kelly J, Keppel C, Kim W, Korsch W, Kramer K, Kumbartzki G, Lerose JJ, Lindgren R, Ma B, Margaziotis DJ, Markowitz P, McCormick K, Meziani ZE, Michaels R, Moffit B, Monaghan P, Munoz Camacho C, Paschke K, Reitz B, Saha A, Sheyor R, Singh J, Slifer K, Sulkosky V, Tobias A, Urciuoli GM, Wang K, Wijesooriya K, Wojtsekhowski B, Woo S, Yang JC, Zheng X, and Zhu L
Abstract: We present experimental results of the first high-precision test of quark-hadron duality in the spin-structure function g_{1} of the neutron and 3He using a polarized 3He target in the four-momentum-transfer-squared range from 0.7 to 4.0 (GeV/c);{2}. Global duality is observed for the spin-structure function g_{1} down to at least Q;{2}=1.8 (GeV/c);{2} in both targets. We have also formed the photon-nucleon asymmetry A1 in the resonance region for 3He and found no strong Q2 dependence above 2.2 (GeV/c);{2}.
Published: 2008
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34. 3He spin-dependent cross sections and sum rules.

Author: Slifer K, Amarian M, Auerbach L, Averett T, Berthot J, Bertin P, Bertozzi B, Black T, Brash E, Brown D, Burtin E, Calarco J, Cates G, Chai Z, Chen JP, Choi S, Chudakov E, Ciofi Degli Atti C, Cisbani E, de Jager CW, Deur A, DiSalvo R, Dieterich S, Djawotho P, Finn M, Fissum K, Fonvieille H, Frullani S, Gao H, Gao J, Garibaldi F, Gasparian A, Gilad S, Gilman R, Glamazdin A, Glashausser C, Glöckle W, Golak J, Goldberg E, Gomez J, Gorbenko V, Hansen JO, Hersman B, Holmes R, Huber GM, Hughes E, Humensky B, Incerti S, Iodice M, Jensen S, Jiang X, Jones C, Jones G, Jones M, Jutier C, Kamada H, Ketikyan A, Kominis I, Korsch W, Kramer K, Kumar K, Kumbartzki G, Kuss M, Lakuriqi E, Laveissiere G, Lerose JJ, Liang M, Liyanage N, Lolos G, Malov S, Marroncle J, McCormick K, McKeown RD, Meziani ZE, Michaels R, Mitchell J, Nogga A, Pace E, Papandreou Z, Pavlin T, Petratos GG, Pripstein D, Prout D, Ransome R, Roblin Y, Rowntree D, Rvachev M, Sabatié F, Saha A, Salmè G, Scopetta S, Skibiński R, Souder P, Saito T, Strauch S, Suleiman R, Takahashi K, Teijiro S, Todor L, Tsubota H, Ueno H, Urciuoli G, Van der Meer R, Vernin P, Voskanian H, Witała H, Wojtsekhowski B, Xiong F, Xu W, Yang JC, Zhang B, and Zolnierczuk P
Abstract: We present a measurement of the spin-dependent cross sections for the 3He over -->(e over -->,e')X reaction in the quasielastic and resonance regions at a four-momentum transfer 0.1< or =Q2< or =0.9 GeV2. The spin-structure functions have been extracted and used to evaluate the nuclear Burkhardt-Cottingham and extended Gerasimov-Drell-Hearn sum rules for the first time. The data are also compared to an impulse approximation calculation and an exact three-body Faddeev calculation in the quasielastic region.
Published: 2008
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35. Deeply virtual compton scattering off the neutron.

Author: Mazouz M, Camsonne A, Camacho CM, Ferdi C, Gavalian G, Kuchina E, Amarian M, Aniol KA, Beaumel M, Benaoum H, Bertin P, Brossard M, Chen JP, Chudakov E, Craver B, Cusanno F, de Jager CW, Deur A, Feuerbach R, Fieschi JM, Frullani S, Garçon M, Garibaldi F, Gayou O, Gilman R, Gomez J, Gueye P, Guichon PA, Guillon B, Hansen O, Hayes D, Higinbotham D, Holmstrom T, Hyde CE, Ibrahim H, Igarashi R, Jiang X, Jo HS, Kaufman LJ, Kelleher A, Kolarkar A, Kumbartzki G, Laveissiere G, Lerose JJ, Lindgren R, Liyanage N, Lu HJ, Margaziotis DJ, Meziani ZE, McCormick K, Michaels R, Michel B, Moffit B, Monaghan P, Nanda S, Nelyubin V, Potokar M, Qiang Y, Ransome RD, Réal JS, Reitz B, Roblin Y, Roche J, Sabatié F, Saha A, Sirca S, Slifer K, Solvignon P, Subedi R, Sulkosky V, Ulmer PE, Voutier E, Wang K, Weinstein LB, Wojtsekhowski B, Zheng X, and Zhu L
Abstract: The present experiment exploits the interference between the deeply virtual Compton scattering (DVCS) and the Bethe-Heitler processes to extract the imaginary part of DVCS amplitudes on the neutron and on the deuteron from the helicity-dependent D(e,e'gamma)X cross section measured at Q2=1.9 GeV2 and xB=0.36. We extract a linear combination of generalized parton distributions (GPDs) particularly sensitive to E_{q}, the least constrained GPD. A model dependent constraint on the contribution of the up and down quarks to the nucleon spin is deduced.
Published: 2007
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36. Investigation of proton-proton short-range correlations via the 12C(e,e'pp) reaction.

Author: Shneor R, Monaghan P, Subedi R, Anderson BD, Aniol K, Annand J, Arrington J, Benaoum H, Benmokhtar F, Bertin P, Bertozzi W, Boeglin W, Chen JP, Choi S, Chudakov E, Cisbani E, Craver B, de Jager CW, Feuerbach RJ, Frullani S, Garibaldi F, Gayou O, Gilad S, Gilman R, Glamazdin O, Gomez J, Hansen JO, Higinbotham DW, Holmstrom T, Ibrahim H, Igarashi R, Jans E, Jiang X, Jiang Y, Kaufman L, Kelleher A, Kolarkar A, Kuchina E, Kumbartzki G, LeRose JJ, Lindgren R, Liyanage N, Margaziotis DJ, Markowitz P, Marrone S, Mazouz M, Meekins D, Michaels R, Moffit B, Nanda S, Perdrisat CF, Piasetzky E, Potokar M, Punjabi V, Qiang Y, Reinhold J, Reitz B, Ron G, Rosner G, Saha A, Sawatzky B, Shahinyan A, Sirca S, Slifer K, Solvignon P, Sulkosky V, Thompson N, Ulmer PE, Urciuoli GM, Voutier E, Wang K, Watson JW, Weinstein LB, Wojtsekhowski B, Wood S, Yao H, Zheng X, and Zhu L
Abstract: We investigated simultaneously the 12C(e,e'p) and 12C(e,e'pp) reactions at Q2=2 (GeV/c)2, xB=1.2, and in an (e, e'p) missing-momentum range from 300 to 600 MeV/c. At these kinematics, with a missing momentum greater than the Fermi momentum of nucleons in a nucleus and far from the delta excitation, short-range nucleon-nucleon correlations are predicted to dominate the reaction. For (9.5+/-2)% of the 12C(e,e'p) events, a recoiling partner proton was observed back-to-back to the 12C(e,e'p) missing-momentum vector, an experimental signature of correlations.
Published: 2007
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37. Recoil-proton polarization in high-energy deuteron photodisintegration with circularly polarized photons.

Author: Jiang X, Arrington J, Benmokhtar F, Camsonne A, Chen JP, Choi S, Chudakov E, Cusanno F, Deur A, Dutta D, Garibaldi F, Gaskell D, Gayou O, Gilman R, Glashauser C, Hamilton D, Hansen O, Higinbotham DW, Holt RJ, de Jager CW, Jones MK, Kaufman LJ, Kinney ER, Kramer K, Lagamba L, de Leo R, Lerose J, Lhuillier D, Lindgren R, Liyanage N, McCormick K, Meziani ZE, Michaels R, Moffit B, Monaghan P, Nanda S, Paschke KD, Perdrisat CF, Punjabi V, Qattan IA, Ransome RD, Reimer PE, Reitz B, Saha A, Schulte EC, Sheyor R, Slifer K, Solvignon P, Sulkosky V, Urciuoli GM, Voutier E, Wang K, Wijesooriya K, Wojtsekhowski B, and Zhu L
Abstract: We measured the angular dependence of the three recoil-proton polarization components in two-body photodisintegration of the deuteron at a photon energy of 2 GeV. These new data provide a benchmark for calculations based on quantum chromodynamics. Two of the five existing models have made predictions of polarization observables. Both explain the longitudinal polarization transfer satisfactorily. Transverse polarizations are not well described, but suggest isovector dominance.
Published: 2007
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38. Precision measurements of the nucleon strange form factors at Q2 approximately 0.1 GeV2.

Author: Acha A, Aniol KA, Armstrong DS, Arrington J, Averett T, Bailey SL, Barber J, Beck A, Benaoum H, Benesch J, Bertin PY, Bosted P, Butaru F, Burtin E, Cates GD, Chao YC, Chen JP, Chudakov E, Cisbani E, Craver B, Cusanno F, De Leo R, Decowski P, Deur A, Feuerbach RJ, Finn JM, Frullani S, Fuchs SA, Fuoti K, Gilman R, Glesener LE, Grimm K, Grames JM, Hansen JO, Hansknecht J, Higinbotham DW, Holmes R, Holmstrom T, Ibrahim H, de Jager CW, Jiang X, Katich J, Kaufman LJ, Kelleher A, King PM, Kolarkar A, Kowalski S, Kuchina E, Kumar KS, Lagamba L, LaViolette P, LeRose J, Lindgren RA, Lhuillier D, Liyanage N, Margaziotis DJ, Markowitz P, Meekins DG, Meziani ZE, Michaels R, Moffit B, Nanda S, Nelyubin V, Otis K, Paschke KD, Phillips SK, Poelker M, Pomatsalyuk R, Potokar M, Prok Y, Puckett A, Qian X, Qiang Y, Reitz B, Roche J, Saha A, Sawatzky B, Singh J, Slifer K, Sirca S, Snyder R, Solvignon P, Souder PA, Stutzman ML, Subedi R, Suleiman R, Sulkosky V, Tobias WA, Ulmer PE, Urciuoli GM, Wang K, Whitbeck A, Wilson R, Wojtsekhowski B, Yao H, Ye Y, Zhan X, Zheng X, Zhou S, and Ziskin V
Abstract: We report new measurements of the parity-violating asymmetry A(PV) in elastic scattering of 3 GeV electrons off hydrogen and 4He targets with approximately 6.0 degrees . The 4He result is A(PV)=(+6.40+/-0.23(stat)+/-0.12(syst))x10(-6). The hydrogen result is A(PV)=(-1.58+/-0.12(stat)+/-0.04(syst))x10(-6). These results significantly improve constraints on the electric and magnetic strange form factors G(E)(s) and G(M)(s). We extract G(E)(s)=0.002+/-0.014+/-0.007 at =0.077 GeV2, and G(E)(s)+0.09G(M)(s)=0.007+/-0.011+/-0.006 at =0.109 GeV2, providing new limits on the role of strange quarks in the nucleon charge and magnetization distributions.
Published: 2007
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39. Scaling tests of the cross section for deeply virtual Compton scattering.

Author: Camacho CM, Camsonne A, Mazouz M, Ferdi C, Gavalian G, Kuchina E, Amarian M, Aniol KA, Beaumel M, Benaoum H, Bertin P, Brossard M, Chen JP, Chudakov E, Craver B, Cusanno F, de Jager CW, Deur A, Feuerbach R, Fieschi JM, Frullani S, Garçon M, Garibaldi F, Gayou O, Gilman R, Gomez J, Gueye P, Guichon PA, Guillon B, Hansen O, Hayes D, Higinbotham D, Holmstrom T, Hyde-Wright CE, Ibrahim H, Igarashi R, Jiang X, Jo HS, Kaufman LJ, Kelleher A, Kolarkar A, Kumbartzki G, Laveissière G, Lerose JJ, Lindgren R, Liyanage N, Lu HJ, Margaziotis DJ, Meziani ZE, McCormick K, Michaels R, Michel B, Moffit B, Monaghan P, Nanda S, Nelyubin V, Potokar M, Qiang Y, Ransome RD, Réal JS, Reitz B, Roblin Y, Roche J, Sabatié F, Saha A, Sirca S, Slifer K, Solvignon P, Subedi R, Sulkosky V, Ulmer PE, Voutier E, Wang K, Weinstein LB, Wojtsekhowski B, Zheng X, and Zhu L
Abstract: We present the first measurements of the e[over -->]p-->epgamma cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region. The Q(2) dependence (from 1.5 to 2.3 GeV(2)) of the helicity-dependent cross section indicates the twist-2 dominance of DVCS, proving that generalized parton distributions (GPDs) are accessible to experiment at moderate Q(2). The helicity-independent cross section is also measured at Q(2)=2.3 GeV(2). We present the first model-independent measurement of linear combinations of GPDs and GPD integrals up to the twist-3 approximation.
Published: 2006
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40. Parity-violating electron scattering from 4He and the strange electric form factor of the nucleon.

Author: Aniol KA, Armstrong DS, Averett T, Benaoum H, Bertin PY, Burtin E, Cahoon J, Cates GD, Chang CC, Chao YC, Chen JP, Choi S, Chudakov E, Craver B, Cusanno F, Decowski P, Deepa D, Ferdi C, Feuerbach RJ, Finn JM, Frullani S, Fuoti K, Garibaldi F, Gilman R, Glamazdin A, Gorbenko V, Grames JM, Hansknecht J, Higinbotham DW, Holmes R, Holmstrom T, Humensky TB, Ibrahim H, de Jager CW, Jiang X, Kaufman LJ, Kelleher A, Kolarkar A, Kowalski S, Kumar KS, Lambert D, LaViolette P, LeRose J, Lhuillier D, Liyanage N, Margaziotis DJ, Mazouz M, McCormick K, Meekins DG, Meziani ZE, Michaels R, Moffit B, Monaghan P, Munoz-Camacho C, Nanda S, Nelyubin V, Neyret D, Paschke KD, Poelker M, Pomatsalyuk R, Qiang Y, Reitz B, Roche J, Saha A, Singh J, Snyder R, Souder PA, Subedi R, Suleiman R, Sulkosky V, Tobias WA, Urciuoli GM, Vacheret A, Voutier E, Wang K, Wilson R, Wojtsekhowski B, and Zheng X
Abstract: We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from 4He at an average scattering angle = 5.7 degrees and a four-momentum transfer Q2 = 0.091 GeV2 . From these data, for the first time, the strange electric form factor of the nucleon G(E)s can be isolated. The measured asymmetry of A(PV) = (6.72 +/- 0.84(stat) +/- 0.21(syst) x 10(-6) yields a value of G(E)s = -0.038 +/- 0.042(stat) +/- 0.010(syst), consistent with zero.
Published: 2006
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41. Q2 dependence of the neutron spin structure function g2(n) at low Q2.

Author: Kramer K, Armstrong DS, Averett TD, Bertozzi W, Binet S, Butuceanu C, Camsonne A, Cates GD, Chen JP, Choi S, Chudakov E, Cusanno F, Deur A, Djawotho P, Dutta D, Finn JM, Gao H, Garibaldi F, Gayou O, Gilman R, Glamazdin A, Gorbenko V, Griffioen KA, Hansen JO, Higinbotham DW, Hinton W, Horn T, de Jager CW, Jiang X, Korsch W, LeRose J, Lhuillier D, Liyanage N, Margaziotis DJ, McCormick K, Meziani ZE, Michaels R, Milbrath B, Moffit B, Nanda S, Perdrisat CF, Pomatsalyuk R, Punjabi V, Reitz B, Roche J, Roché R, Roedelbronn M, Savvinov N, Secrest J, Singh J, Sirca S, Slifer K, Solvignon P, Steiner DJ, Suleiman R, Sulkosky V, Tobias A, Vacheret A, Xiao Y, Zheng X, Zhou J, Zhu L, Zhu X, and Zołnierczuk PA
Abstract: We present the first measurement of the Q2 dependence of the neutron spin structure function g2(n) at five kinematic points covering 0.57 (GeV/c)2 < or = Q2 < or = 1.34 (GeV/c)2 at x approximately = 0.2. Though the naive quark-parton model predicts g2 = 0, nonzero values occur in more realistic models of the nucleon which include quark-gluon correlations, finite quark masses, or orbital angular momentum. When scattering from a noninteracting quark, g2(n) can be predicted using next-to-leading order fits to world data for g1(n). Deviations from this prediction provide an opportunity to examine QCD dynamics in nucleon structure. Our results show a positive deviation from this prediction at lower Q2, indicating that contributions such as quark-gluon interactions may be important. Precision data obtained for g1(n) are consistent with next-to-leading order fits to world data.
Published: 2005
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42. Recoil polarization for delta excitation in pion electroproduction.

Author: Kelly JJ, Roché RE, Chai Z, Jones MK, Gayou O, Sarty AJ, Frullani S, Aniol K, Beise EJ, Benmokhtar F, Bertozzi W, Boeglin WU, Botto T, Brash EJ, Breuer H, Brown E, Burtin E, Calarco JR, Cavata C, Chang CC, Chant NS, Chen JP, Coman M, Crovelli D, De Leo R, Dieterich S, Escoffier S, Fissum KG, Garde V, Garibaldi F, Georgakopoulus S, Gilad S, Gilman R, Glashausser C, Hansen JO, Higinbotham DW, Hotta A, Huber GM, Ibrahim H, Iodice M, de Jager CW, Jiang X, Klimenko A, Kozlov A, Kumbartzki G, Kuss M, Lagamba L, Laveissière G, Lerose JJ, Lindgren RA, Liyanage N, Lolos GJ, Lourie RW, Margaziotis DJ, Marie F, Markowitz P, McAleer S, Meekins D, Michaels R, Milbrath BD, Mitchell J, Nappa J, Neyret D, Perdrisat CF, Potokar M, Punjabi VA, Pussieux T, Ransome RD, Roos PG, Rvachev M, Saha A, Sirca S, Suleiman R, Strauch S, Templon JA, Todor L, Ulmer PE, Urciuoli GM, Weinstein LB, Wijesooriya K, Wojtsekhowski B, Zheng X, and Zhu L
Abstract: We measured angular distributions of recoil-polarization response functions for neutral pion electroproduction for W = 1.23 GeV at Q(2) = 1.0 (GeV/c)(2), obtaining 14 separated response functions plus 2 Rosenbluth combinations; of these, 12 have been observed for the first time. Dynamical models do not describe quantities governed by imaginary parts of interference products well, indicating the need for adjusting magnitudes and phases for nonresonant amplitudes. We performed a nearly model-independent multipole analysis and obtained values for Re (S(1+)/M(1+)) = -(6.84 +/- 0.15)% and Re (E(1+)/M(1+)) = -(2.91 +/- 0.19)% that are distinctly different from those from the traditional Legendre analysis based upon M1+ dominance and ll(pi) < or = 1 truncation.
Published: 2005
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43. Quasielastic 3He(e,e'p)2H reaction at Q2 = 1.5 GeV2 for recoil momenta up to 1 GeV/c.

Author: Rvachev MM, Benmokhtar F, Penel-Nottaris E, Aniol KA, Bertozzi W, Boeglin WU, Butaru F, Calarco JR, Chai Z, Chang CC, Chen JP, Chudakov E, Cisbani E, Cochran A, Cornejo J, Dieterich S, Djawotho P, Duran W, Epstein MB, Finn JM, Fissum KG, Frahi-Amroun A, Frullani S, Furget C, Garibaldi F, Gayou O, Gilad S, Gilman R, Glashausser C, Hansen JO, Higinbotham DW, Hotta A, Hu B, Iodice M, Iomni R, de Jager CW, Jiang X, Jones MK, Kelly JJ, Kox S, Kuss M, Laget JM, De Leo R, Lerose JJ, Liatard E, Lindgren R, Liyanage N, Lourie RW, Malov S, Margaziotis DJ, Markowitz P, Merchez F, Michaels R, Mitchell J, Mougey J, Perdrisat CF, Punjabi VA, Quéméner G, Ransome RD, Réal JS, Roché R, Sabatié F, Saha A, Simon D, Strauch S, Suleiman R, Tamae T, Templon JA, Tieulent R, Ueno H, Ulmer PE, Urciuoli GM, Voutier E, Wijesooriya K, and Wojtsekhowski B
Abstract: We have studied the quasielastic 3He(e,e(')p)2H reaction in perpendicular coplanar kinematics, with the energy and the momentum transferred by the electron fixed at 840 MeV and 1502 MeV/c, respectively. The 3He(e,e(')p)2H cross section was measured for missing momenta up to 1000 MeV/c, while the A(TL) asymmetry was extracted for missing momenta up to 660 MeV/c. For missing momenta up to 150 MeV/c, the cross section is described by variational calculations using modern 3He wave functions. For missing momenta from 150 to 750 MeV/c, strong final-state interaction effects are observed. Near 1000 MeV/c, the experimental cross section is more than an order of magnitude larger than predicted by available theories. The A(TL) asymmetry displays characteristic features of broken factorization with a structure that is similar to that generated by available models.
Published: 2005
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44. Measurement of the 3He(e,e'p)pn reaction at high missing energies and momenta.

Author: Benmokhtar F, Rvachev MM, Penel-Nottaris E, Aniol KA, Bertozzi W, Boeglin WU, Butaru F, Calarco JR, Chai Z, Chang CC, Chen JP, Chudakov E, Cisbani E, Cochran A, Cornejo J, Dieterich S, Djawotho P, Duran W, Epstein MB, Finn JM, Fissum KG, Frahi-Amroun A, Frullani S, Furget C, Garibaldi F, Gayou O, Gilad S, Gilman R, Glashausser C, Hansen JO, Higinbotham DW, Hotta A, Hu B, Iodice M, Iomni R, de Jager CW, Jiang X, Jones MK, Kelly JJ, Kox S, Kuss M, Laget JM, De Leo R, Lerose JJ, Liatard E, Lindgren R, Liyanage N, Lourie RW, Malov S, Margaziotis DJ, Markowitz P, Merchez F, Michaels R, Mitchell J, Mougey J, Perdrisat CF, Punjabi VA, Quéméner G, Ransome RD, Réal JS, Roché R, Sabatié F, Saha A, Simon D, Strauch S, Suleiman R, Tamae T, Templon JA, Tieulent R, Ueno H, Ulmer PE, Urciuoli GM, Voutier E, Wijesooriya K, and Wojtsekhowski B
Abstract: Results of the Jefferson Lab Hall A quasielastic 3He(e,e'p)pn measurements are presented. These measurements were performed at fixed transferred momentum and energy, q=1502 MeV/c and omega=840 MeV, respectively, for missing momenta p(m) up to 1 GeV/c and missing energies in the continuum region, up to pion threshold; this kinematic coverage is much more extensive than that of any previous experiment. The cross section data are presented along with the effective momentum density distribution and compared to theoretical models.
Published: 2005
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45. Measurement of the generalized forward spin polarizabilities of the neutron.

Author: Amarian M, Auerbach L, Averett T, Berthot J, Bertin P, Bertozzi W, Black T, Brash E, Brown D, Burtin E, Calarco J, Cates G, Chai Z, Chen JP, Choi S, Chudakov E, Cisbani E, de Jager CW, Deur A, DiSalvo R, Dieterich S, Djawotho P, Finn JM, Fissum K, Fonvieille H, Frullani S, Gao H, Gao J, Garibaldi F, Gasparian A, Gilad S, Gilman R, Glamazdin A, Glashausser C, Goldberg E, Gomez J, Gorbenko V, Hansen JO, Hersman B, Holmes R, Huber GM, Hughes E, Humensky B, Incerti S, Iodice M, Jensen S, Jiang X, Jones C, Jones G, Jones M, Jutier C, Ketikyan A, Kominis I, Korsch W, Kramer K, Kumar K, Kumbartzki G, Kuss M, Lakuriqi E, Laveissiere G, Lerose J, Liang M, Liyanage N, Lolos G, Malov S, Marroncle J, McCormick K, McKeown R, Meziani ZE, Michaels R, Mitchell J, Papandreou Z, Pavlin T, Petratos GG, Pripstein D, Prout D, Ransome R, Roblin Y, Rowntree D, Rvachev M, Sabatie F, Saha A, Slifer K, Souder P, Saito T, Strauch S, Suleiman R, Takahashi K, Teijiro S, Todor L, Tsubota H, Ueno H, Urciuoli G, Van der Meer R, Vernin P, Voskanian H, Wojtsekhowski B, Xiong F, Xu W, Yang JC, Zhang B, and Zołnierczuk PA
Abstract: The generalized forward spin polarizabilities gamma(0) and delta(LT) of the neutron have been extracted for the first time in a Q2 range from 0.1 to 0.9 GeV2. Since gamma(0) is sensitive to nucleon resonances and delta(LT) is insensitive to the Delta resonance, it is expected that the pair of forward spin polarizabilities should provide benchmark tests of the current understanding of the chiral dynamics of QCD. The new results on delta(LT) show significant disagreement with chiral perturbation theory calculations, while the data for gamma(0) at low Q2 are in good agreement with a next-to-leading-order relativistic baryon chiral perturbation theory calculation. The data show good agreement with the phenomenological MAID model.
Published: 2004
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46. Measurement of the generalized polarizabilities of the proton in virtual Compton scattering at Q2=0.92 and 1.76 GeV2.

Author: Laveissière G, Todor L, Degrande N, Jaminion S, Jutier C, Di Salvo R, Van Hoorebeke L, Alexa LC, Anderson BD, Aniol KA, Arundell K, Audit G, Auerbach L, Baker FT, Baylac M, Berthot J, Bertin PY, Bertozzi W, Bimbot L, Boeglin WU, Brash EJ, Breton V, Breuer H, Burtin E, Calarco JR, Cardman LS, Cavata C, Chang CC, Chen JP, Chudakov E, Cisbani E, Dale DS, de Jager CW, De Leo R, Deur A, d'Hose N, Dodge GE, Domingo JJ, Elouadrhiri L, Epstein MB, Ewell LA, Finn JM, Fissum KG, Fonvieille H, Fournier G, Frois B, Frullani S, Furget C, Gao H, Gao J, Garibaldi F, Gasparian A, Gilad S, Gilman R, Glamazdin A, Glashausser C, Gomez J, Gorbenko V, Grenier P, Guichon PA, Hansen JO, Holmes R, Holtrop M, Howell C, Huber GM, Hyde-Wright CE, Incerti S, Iodice M, Jardillier J, Jones MK, Kahl W, Kato S, Katramatou AT, Kelly JJ, Kerhoas S, Ketikyan A, Khayat M, Kino K, Kox S, Kramer LH, Kumar KS, Kumbartzki G, Kuss M, Leone A, LeRose JJ, Liang M, Lindgren RA, Liyanage N, Lolos GJ, Lourie RW, Madey R, Maeda K, Malov S, Manley DM, Marchand C, Marchand D, Margaziotis DJ, Markowitz P, Marroncle J, Martino J, McCormick K, McIntyre J, Mehrabyan S, Merchez F, Meziani ZE, Michaels R, Miller GW, Mougey JY, Nanda SK, Neyret D, Offermann EA, Papandreou Z, Pasquini B, Perdrisat CF, Perrino R, Petratos GG, Platchkov S, Pomatsalyuk R, Prout DL, Punjabi VA, Pussieux T, Quémenér G, Ransome RD, Ravel O, Real JS, Renard F, Roblin Y, Rowntree D, Rutledge G, Rutt PM, Saha A, Saito T, Sarty AJ, Serdarevic A, Smith T, Smirnov G, Soldi K, Sorokin P, Souder PA, Suleiman R, Templon JA, Terasawa T, Tieulent R, Tomasi-Gustaffson E, Tsubota H, Ueno H, Ulmer PE, Urciuoli GM, Vanderhaeghen M, Van De Vyver R, Van der Meer RL, Vernin P, Vlahovic B, Voskanyan H, Voutier E, Watson JW, Weinstein LB, Wijesooriya K, Wilson R, Wojtsekhowski BB, Zainea DG, Zhang WM, Zhao J, and Zhou ZL
Abstract: We report a virtual Compton scattering study of the proton at low c.m. energies. We have determined the structure functions P(LL)-P(TT)/epsilon and P(LT), and the electric and magnetic generalized polarizabilities (GPs) alpha(E)(Q2) and beta(M)(Q2) at momentum transfer Q(2)=0.92 and 1.76 GeV2. The electric GP shows a strong falloff with Q2, and its global behavior does not follow a simple dipole form. The magnetic GP shows a rise and then a falloff; this can be interpreted as the dominance of a long-distance diamagnetic pion cloud at low Q2, compensated at higher Q2 by a paramagnetic contribution from piN intermediate states.
Published: 2004
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47. Q2 evolution of the neutron spin structure moments using a 3He target.

Author: Amarian M, Auerbach L, Averett T, Berthot J, Bertin P, Bertozzi B, Black T, Brash E, Brown D, Burtin E, Calarco J, Cates G, Chai Z, Chen JP, Choi S, Chudakov E, Cisbani E, De Jager CW, Deur A, DiSalvo R, Dieterich S, Djawotho P, Finn M, Fissum K, Fonvieille H, Frullani S, Gao H, Gao J, Garibaldi F, Gasparian A, Gilad S, Gilman R, Glamazdin A, Glashausser C, Goldberg E, Gomez J, Gorbenko V, Hansen JO, Hersman B, Holmes R, Huber GM, Hughes E, Humensky B, Incerti S, Iodice M, Jensen S, Jiang X, Jones C, Jones G, Jones M, Jutier C, Ketikyan A, Kominis I, Korsch W, Kramer K, Kumar K, Kumbartzki G, Kuss M, Lakuriqi E, Laveissiere G, Lerose J, Liang M, Liyanage N, Lolos G, Malov S, Marroncle J, McCormick K, McKeown R, Meziani ZE, Michaels R, Mitchell J, Papandreou Z, Pavlin T, Petratos GG, Pripstein D, Prout D, Ransome R, Roblin Y, Rowntree D, Rvachev M, Sabatie F, Saha A, Slifer K, Souder P, Saito T, Strauch S, Suleiman R, Takahashi K, Teijiro S, Todor L, Tsubota H, Ueno H, Urciuoli G, Van Der Meer R, Vernin P, Voskanian H, Wojtsekhowski B, Xiong F, Xu W, Yang JC, Zhang B, and Zolnierczuk P
Abstract: We have measured the spin structure functions g(1) and g(2) of 3He in a double-spin experiment by inclusively scattering polarized electrons at energies ranging from 0.862 to 5.058 GeV off a polarized 3He target at a 15.5 degrees scattering angle. Excitation energies covered the resonance and the onset of the deep inelastic regions. We have determined for the first time the Q2 evolution of Gamma(1)(Q2)= integral (1)(0)g(1)(x,Q2)dx, Gamma(2)(Q2)= integral (1)(0)g(2)(x,Q2)dx, and d(2)(Q2)= integral (1)(0)x(2)[2g(1)(x,Q2)+3g(2)(x,Q2)]dx for the neutron in the range 0.1< or =Q2< or =0.9 GeV2 with good precision. Gamma(1)(Q2) displays a smooth variation from high to low Q2. The Burkhardt-Cottingham sum rule holds within uncertainties and d(2) is nonzero over the measured range.
Published: 2004
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48. Precision measurement of the neutron spin asymmetryA(n)(1) and spin-flavor decomposition in the valence quark region.

Author: Zheng X, Aniol K, Armstrong DS, Averett TD, Bertozzi W, Binet S, Burtin E, Busato E, Butuceanu C, Calarco J, Camsonne A, Cates GD, Chai Z, Chen JP, Choi S, Chudakov E, Cusanno F, Leo RD, Deur A, Dieterich S, Dutta D, Finn JM, Frullani S, Gao H, Gao J, Garibaldi F, Gilad S, Gilman R, Gomez J, Hansen JO, Higinbotham DW, Hinton W, Horn T, De Jager CW, Jiang X, Kaufman L, Kelly J, Korsch W, Kramer K, LeRose J, Lhuillier D, Liyanage N, Margaziotis DJ, Marie F, Markowitz P, McCormick K, Meziani ZE, Michaels R, Moffit B, Nanda S, Neyret D, Phillips SK, Powell A, Pussieux T, Reitz B, Roche J, Roche R, Roedelbronn M, Ron G, Rvachev M, Saha A, Savvinov N, Singh J, Sirca S, Slifer K, Solvignon P, Souder P, Steiner DJ, Strauch S, Sulkosky V, Tobias A, Urciuoli G, Vacheret A, Wojtsekhowski B, Xiang H, Xiao Y, Xiong F, Zhang B, Zhu L, Zhu X, and Zołnierczuk PA
Abstract: We have measured the neutron spin asymmetry A(n)(1) with high precision at three kinematics in the deep inelastic region at x=0.33, 0.47, and 0.60, and Q(2)=2.7, 3.5, and 4.8 (GeV/c)(2), respectively. Our results unambiguously show, for the first time, that A(n)(1) crosses zero around x=0.47 and becomes significantly positive at x=0.60. Combined with the world proton data, polarized quark distributions were extracted. Our results, in general, agree with relativistic constituent quark models and with perturbative quantum chromodynamics (PQCD) analyses based on the earlier data. However they deviate from PQCD predictions based on hadron helicity conservation.
Published: 2004
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49. Polarization transfer in the 4He(e-->,e'p-->)3H reaction up to Q2=2.6 (GeV/c)2.

Author: Strauch S, Dieterich S, Aniol KA, Annand JR, Baker OK, Bertozzi W, Boswell M, Brash EJ, Chai Z, Chen JP, Christy ME, Chudakov E, Cochran A, De Leo R, Ent R, Epstein MB, Finn JM, Fissum KG, Forest TA, Frullani S, Garibaldi F, Gasparian A, Gayou O, Gilad S, Gilman R, Glashausser C, Gomez J, Gorbenko V, Gueye PL, Hansen JO, Higinbotham DW, Hu B, Hyde-Wright CE, Ireland DG, Jackson C, de Jager CW, Jiang X, Jones C, Jones MK, Kellie JD, Kelly JJ, Keppel CE, Kumbartzki G, Kuss M, LeRose JJ, Livingston K, Liyanage N, Malov S, Margaziotis DJ, Meekins D, Michaels R, Mitchell JH, Nanda SK, Nappa J, Perdrisat CF, Punjabi VA, Ransome RD, Roché R, Rosner G, Rvachev M, Sabatie F, Saha A, Sarty A, Udias JM, Ulmer PE, Urciuoli GM, van den Brand JF, Vignote JR, Watts DP, Weinstein LB, Wijesooriya K, and Wojtsekhowski B
Abstract: We have measured the proton recoil polarization in the 4He(e-->,e(')p-->)4H reaction at Q(2)=0.5, 1.0, 1.6, and 2.6 (GeV/c)(2). The measured ratio of polarization transfer coefficients differs from a fully relativistic calculation, favoring the inclusion of a medium modification of the proton form factors predicted by a quark-meson coupling model. In addition, the measured induced polarizations agree reasonably well with the fully relativistic calculation indicating that the treatment of final-state interactions is under control.
Published: 2003
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50. Cross-section measurement of charged-pion photoproduction from hydrogen and deuterium.

Author: Zhu LY, Arrington J, Averett T, Beise E, Calarco J, Chang T, Chen JP, Chudakov E, Coman M, Clasie B, Crawford C, Dieterich S, Dohrmann F, Dutta D, Fissum K, Frullani S, Gao H, Gilman R, Glashausser C, Gomez J, Hafidi K, Hansen JO, Higinbotham DW, Holt RJ, De Jager CW, Jiang X, Kinney E, Kramer K, Kumbartzki G, LeRose J, Liyanage N, Mack D, Markowitz P, McCormick K, Meekins D, Meziani ZE, Michaels R, Mitchell J, Nanda S, Potterveld D, Ransome R, Reimer PE, Reitz B, Saha A, Schulte EC, Seely J, Sirca S, Strauch S, Sulkosky V, Vlahovic B, Weinstein LB, Wijesooriya K, Williamson CF, Wojtsekhowski B, Xiang H, Xiong F, Xu W, Zeng J, and Zheng X
Abstract: We have measured the differential cross section for the gamman-->pi(-)p and gammap-->pi(+)n reactions at theta(c.m.)=90 degrees in the photon energy range from 1.1 to 5.5 GeV at Jefferson Lab (JLab). The data at E(gamma) greater, similar 3.3 GeV exhibit a global scaling behavior for both pi(-) and pi(+) photoproduction, consistent with the constituent counting rule and the existing pi(+) photoproduction data. Possible oscillations around the scaling value are suggested by these new data. The data show enhancement in the scaled cross section at a center-of-mass energy near 2.2 GeV. The cross section ratio of exclusive pi(-) to pi(+) photoproduction at high energy is consistent with the prediction based on one-hard-gluon-exchange diagrams.
Published: 2003
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