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11 results on '"R. Feuerbach"'

1. Measurement of the 3He spin-structure functions and of neutron (3He) spin-dependent sum rules at 0.035 ≤ Q2 ≤ 0.24 GeV2

Author

V. Sulkosky, J.T. Singh, C. Peng, J.-P. Chen, A. Deur, S. Abrahamyan, K.A. Aniol, D.S. Armstrong, T. Averett, S.L. Bailey, A. Beck, P. Bertin, F. Butaru, W. Boeglin, A. Camsonne, G.D. Cates, C.C. Chang, Seonho Choi, E. Chudakov, L. Coman, J.C. Cornejo, B. Craver, F. Cusanno, R. De Leo, C.W. de Jager, J.D. Denton, S. Dhamija, R. Feuerbach, J.M. Finn, S. Frullani, K. Fuoti, H. Gao, F. Garibaldi, O. Gayou, R. Gilman, A. Glamazdin, C. Glashausser, J. Gomez, J.-O. Hansen, D. Hayes, B. Hersman, D.W. Higinbotham, T. Holmstrom, T.B. Humensky, C.E. Hyde, H. Ibrahim, M. Iodice, X. Jiang, L.J. Kaufman, A. Kelleher, K.E. Keister, W. Kim, A. Kolarkar, N. Kolb, W. Korsch, K. Kramer, G. Kumbartzki, L. Lagamba, V. Lainé, G. Laveissiere, J.J. Lerose, D. Lhuillier, R. Lindgren, N. Liyanage, H.-J. Lu, B. Ma, D.J. Margaziotis, P. Markowitz, K. McCormick, M. Meziane, Z.-E. Meziani, R. Michaels, B. Moffit, P. Monaghan, S. Nanda, J. Niedziela, M. Niskin, R. Pandolfi, K.D. Paschke, M. Potokar, A.J.R. Puckett, V.A. Punjabi, Y. Qiang, R. Ransome, B. Reitz, R. Roché, A. Saha, A. Shabetai, S. Širca, K. Slifer, R. Snyder, P. Solvignon, R. Stringer, R. Subedi, W.A. Tobias, N. Ton, P.E. Ulmer, G.M. Urciuoli, A. Vacheret, E. Voutier, K. Wang, L. Wan, B. Wojtsekhowski, S. Woo, H. Yao, J. Yuan, X. Zhan, X. Zheng, and L. Zhu

Subjects
Physics, QC1-999
Abstract

The spin-structure functions g1 and g2, and the spin-dependent partial cross-section σTT have been extracted from the polarized cross-sections differences, Δσ∥(ν,Q2) and Δσ⊥(ν,Q2) measured for the He3→(e→,e′)X reaction, in the E97-110 experiment at Jefferson Lab. Polarized electrons with energies from 1.147 to 4.404 GeV were scattered at angles of 6∘ and 9∘ from a longitudinally or transversely polarized 3He target. The data cover the kinematic regions of the quasi-elastic, resonance production and beyond. From the extracted spin-structure functions, the first moments Γ1‾(Q2), Γ2(Q2) and ITT(Q2) are evaluated with high precision for the neutron in the Q2 range from 0.035 to 0.24GeV2. The comparison of the data and the chiral effective field theory predictions reveals the importance of proper treatment of the Δ degree of freedom for spin observables.

Published
2020
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2. 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

3. 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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4. 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

5. Proton Polarimeter Calibration between 82 and 217 MeV

Author

Yannick Rousseau, J. Roche, S. Strauch, E. J. Brash, R. Feuerbach, Douglas Higinbotham, M. K. Jones, Ronald Gilman, Guy Ron, Byeonghun Lee, A. J. Sarty, B. Sawatzky, A. Beck, Suyong Choi, Emily M. McCullough, E. Piasetzky, A. Camsonne, X. Jiang, J. Dumas, J. Glister, M. Paolone, and S. May-Tal Beck

Subjects
Physics, Elastic scattering, Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, Scattering, business.industry, FOS: Physical sciences, Polarimeter, Polarization (waves), 7. Clean energy, 01 natural sciences, Nuclear physics, Optics, 0103 physical sciences, Figure of merit, Nuclear Experiment (nucl-ex), 010306 general physics, Nucleon, business, Nuclear Experiment, Instrumentation, Dimensionless quantity
Abstract

The proton analyzing power in carbon has been measured for energies of 82 to 217 MeV and proton scattering angles of 5 to 41 degrees. The measurements were carried out using polarized protons from the elastic scattering H(pol. e, pol. p) reaction and the Focal Plane Polarimeter (FPP) in Hall A of Jefferson Lab. A new parameterization of the FPP p-C analyzing power was fit to the data, which is in good agreement with previous parameterizations and provides an extension to lower energies and larger angles. The main conclusions are that all polarimeters to date give consistent measurements of the carbon analyzing power, independently of the details of their construction and that measuring on a larger angular range significantly improves the polarimeter figure of merit at low energies., Comment: 18 pages, 6 figures, submitted to NIM A

Published
2009
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6. Measurements of the Proton Elastic-Form-Factor RatioμpGEp/GMpat Low Momentum Transfer

Author

G. Ron, J. Glister, B. Lee, K. Allada, W. Armstrong, J. Arrington, A. Beck, F. Benmokhtar, B. L. Berman, W. Boeglin, E. Brash, A. Camsonne, J. Calarco, J. P. Chen, Seonho Choi, E. Chudakov, L. Coman, B. Craver, F. Cusanno, J. Dumas, C. Dutta, R. Feuerbach, A. Freyberger, S. Frullani, F. Garibaldi, R. Gilman, O. Hansen, D. W. Higinbotham, T. Holmstrom, C. E. Hyde, H. Ibrahim, Y. Ilieva, C. W. de Jager, X. Jiang, M. K. Jones, H. Kang, A. Kelleher, E. Khrosinkova, E. Kuchina, G. Kumbartzki, J. J. LeRose, R. Lindgren, P. Markowitz, S. May-Tal Beck, E. McCullough, D. Meekins, M. Meziane, Z.-E. Meziani, R. Michaels, B. Moffit, B. E. Norum, Y. Oh, M. Olson, M. Paolone, K. Paschke, C. F. Perdrisat, E. Piasetzky, M. Potokar, R. Pomatsalyuk, I. Pomerantz, A. Puckett, V. Punjabi, X. Qian, Y. Qiang, R. Ransome, M. Reyhan, J. Roche, Y. Rousseau, A. Saha, A. J. Sarty, B. Sawatzky, E. Schulte, M. Shabestari, A. Shahinyan, R. Shneor, S. Širca, K. Slifer, P. Solvignon, J. Song, R. Sparks, R. Subedi, S. Strauch, G. M. Urciuoli, K. Wang, B. Wojtsekhowski, X. Yan, H. Yao, X. Zhan, and X. Zhu

Subjects
Physics, Proton, 010308 nuclear & particles physics, Hadron, Momentum transfer, Form factor (quantum field theory), General Physics and Astronomy, Elementary particle, 01 natural sciences, Baryon, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon, Dimensionless quantity
Abstract

High-precision measurements of the proton elastic form-factor ratio, {mu}{sub p}G{sub E}{sup p}/G{sub M}{sup p}, have been made at four-momentum transfer, Q{sup 2}, values between 0.2 and 0.5 GeV{sup 2}. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q{sup 2} range the deviation from unity is primarily due to G{sub E}{sup p} being smaller than expected.

Published
2007
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7. Measurements of the proton elastic-form-factor ratio mu pG p E/G p M at low momentum transfer

Author

G, Ron, J, Glister, B, Lee, K, Allada, W, Armstrong, J, Arrington, A, Beck, F, Benmokhtar, B L, Berman, W, Boeglin, E, Brash, A, Camsonne, J, Calarco, J P, Chen, Seonho, Choi, E, Chudakov, L, Coman, B, Craver, F, Cusanno, J, Dumas, C, Dutta, R, Feuerbach, A, Freyberger, S, Frullani, F, Garibaldi, R, Gilman, O, Hansen, D W, Higinbotham, T, Holmstrom, C E, Hyde, H, Ibrahim, Y, Ilieva, C W, de Jager, X, Jiang, M K, Jones, H, Kang, A, Kelleher, E, Khrosinkova, E, Kuchina, G, Kumbartzki, J J, LeRose, R, Lindgren, P, Markowitz, S, May-Tal Beck, E, McCullough, D, Meekins, M, Meziane, Z-E, Meziani, R, Michaels, B, Moffit, B E, Norum, Y, Oh, M, Olson, M, Paolone, K, Paschke, C F, Perdrisat, E, Piasetzky, M, Potokar, R, Pomatsalyuk, I, Pomerantz, A, Puckett, V, Punjabi, X, Qian, Y, Qiang, R, Ransome, M, Reyhan, J, Roche, Y, Rousseau, A, Saha, A J, Sarty, B, Sawatzky, E, Schulte, M, Shabestari, A, Shahinyan, R, Shneor, S, Sirca, K, Slifer, P, Solvignon, J, Song, R, Sparks, R, Subedi, S, Strauch, G M, Urciuoli, K, Wang, B, Wojtsekhowski, X, Yan, H, Yao, X, Zhan, and X, Zhu

Abstract

High-precision measurements of the proton elastic form-factor ratio, mu pG p E/G p M, have been made at four-momentum transfer, Q2, values between 0.2 and 0.5 GeV2. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q2 range the deviation from unity is primarily due to G p E being smaller than expected.

Published
2007

8. 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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9. 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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10. 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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11. 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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