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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, Zolnierczuk P. Q2 evolution of the neutron spin structure moments using a 3He target. Phys Rev Lett 2004; 92:022301. [PMID: 14753931 DOI: 10.1103/physrevlett.92.022301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2003] [Indexed: 05/24/2023]
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.
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Affiliation(s)
- M Amarian
- Yerevan Physics Institute, Yerevan 375036, Armenia
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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, Zołnierczuk PA. Precision measurement of the neutron spin asymmetryA(n)(1) and spin-flavor decomposition in the valence quark region. Phys Rev Lett 2004; 92:012004. [PMID: 14753984 DOI: 10.1103/physrevlett.92.012004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2003] [Indexed: 05/24/2023]
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.
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Affiliation(s)
- X Zheng
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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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, Zheng X. Cross-section measurement of charged-pion photoproduction from hydrogen and deuterium. Phys Rev Lett 2003; 91:022003. [PMID: 12906473 DOI: 10.1103/physrevlett.91.022003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2002] [Indexed: 05/24/2023]
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.
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Affiliation(s)
- L Y Zhu
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Amarian M, Auerbach L, Averett T, Berthot J, Bertin P, Bertozzi W, Black T, Brash E, Brown D, Burtin E, Calarco JR, Cates GD, 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 FW, Holmes R, Huber GM, Hughes EW, Humensky TB, Incerti S, Iodice M, Jensen S, Jiang X, Jones C, Jones GM, Jones M, Jutier C, Ketikyan A, Kominis I, Korsch W, Kramer K, Kumar KS, 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 PA, 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, Zolnierczuk P. Q2 evolution of the generalized Gerasimov-Drell-Hearn integral for the neutron using a 3He target. Phys Rev Lett 2002; 89:242301. [PMID: 12484938 DOI: 10.1103/physrevlett.89.242301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2002] [Indexed: 05/24/2023]
Abstract
We present data on the inclusive scattering of polarized electrons from a polarized 3He target at energies from 0.862 to 5.06 GeV, obtained at a scattering angle of 15.5 degrees. Our data include measurements from the quasielastic peak, through the nucleon resonance region, and beyond, and were used to determine the virtual photon cross-section difference sigma(1/2)-sigma(3/2). We extract the extended Gerasimov-Drell-Hearn integral for the neutron in the range of four-momentum transfer squared Q2 of 0.1-0.9 GeV2.
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Affiliation(s)
- M Amarian
- Istituto Nazionale di Fiscica Nucleare, Sezione Sanità, 00161 Roma, Italy
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Ulmer PE, Aniol KA, Arenhövel H, Chen JP, Chudakov E, Crovelli D, Finn JM, Fissum KG, Gayou O, Gomez J, Hansen JO, De Jager CW, Jeschonnek S, Jones MK, Kuss M, LeRose JJ, Liang M, Lindgren RA, Malov S, Meekins D, Michaels R, Mitchell J, Perdrisat CF, Punjabi V, Roché R, Sabatie F, Saha A, Suleiman R, Todor L, Wojtsekhowski BB. 2H(e,e(')p)n reaction at high recoil momenta. Phys Rev Lett 2002; 89:062301. [PMID: 12190578 DOI: 10.1103/physrevlett.89.062301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2001] [Indexed: 05/23/2023]
Abstract
The 2H(e,e(')p)n cross section was measured in Hall A of the Thomas Jefferson National Accelerator Facility near the top of the quasielastic peak (x(Bj)=0.964) at a four-momentum transfer squared, Q(2)=0.665 (GeV/c) (2) (omega=0.368 GeV, W=2.057 GeV), and for recoil momenta up to 550 MeV/c. The measured cross section deviates by 1-2sigma from a state-of-the-art calculation at low recoil momenta. At high recoil momenta the cross section is well described by the same calculation; however, in this region, final-state interactions and interaction currents are predicted to be large, and alternative choices of nucleon-nucleon potential and nucleon current operator may result in significant spread in the calculations.
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Affiliation(s)
- P E Ulmer
- Old Dominion University, Norfolk, Virginia 23529, USA
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