1. Measurement of the x- and Q2-dependence of the asymmetry A1 on the nucleon
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Dharmawardane, Kv, Kuhn, Se, Bosted, P, Prok, Y, Adams, G, Ambrozewicz, P, Anghinolfi, Marco, Asryan, G, Avakian, H, Bagdasaryan, H, Baillie, N, Ball, Jp, Baltzell, Na, Barrow, S, Batourine, V, Battaglieri, Marco, Beard, K, Bedlinskiy, I, Bektasoglu, M, Bellis, M, Benmouna, N, Biselli, As, Bonner, Be, Bouchigny, S, Boiarinov, S, Bradford, R, Branford, D, Brooks, Wk, Bultmann, S, Burkert, Vd, Butuceanu, C, Calarco, Jr, Careccia, Sl, Carman, Ds, Carnahan, B, Cazes Antoine Jacques, Chen, S, Cole, Pl, Collins, P, Coltharp, P, Cords, D, Corvisiero, Pietro, Crabb, D, Crannell, H, Crede, V, Cummings, Jp, De Masi, R, Devita, R, De Sanctis Enzo, Degtyarenko, Pv, Denizli, H, Dennis, L, Deur, A, Djalali, C, Dodge, Ge, Donnelly, J, Doughty, D, Draigovitsch, P, Dugger, M, Dytman, S, Dzyubak, Op, Egiyan, H, Egiyan, Ks, Elouadrhiri, L, Eugenio, P, Fatemi, R, Fedotov, G, Feuerbach, Rj, Forest, Ta, Funsten, H, Garcon, M, Gavalian, G, Gilfoyle, Gp, Giovanetti, Kl, Girod, Fx, Goetz, Jt, Golovatch, Evgueni, Gonenc, A, Gothe, Rw, Griffioen, Ka, Guidal, M, Guillo, M, Guler, N, Guo, L, Gyurjyan, V, Hadjidakis, Cynthia, Hafidi, K, Hakobyan, Rs, Hardie, J, Heddle, D, Hersman, Fw, Hicks, K, Hleiqawi, I, Holtrop, M, Huertas, M, Hyde Wriyht CE, Ilieva, Y, Ireland, Dg, Ishkhanov, Bs, Isupov, El, Ito, Mm, Jenkins, D, Jo, Hs, Joo, K, Juengst, Hg, Keith, C, Kellie, Jd, Khandaker, M, Kim, Ky, Kim, K, Kim, W, Klein, A, Klein, Fj, Klusman, M, Kossov, M, Kramer, Lh, Kubarovsky, V, Kuhn, J, Kuleshov, Sv, Lachniet, J, Laget, Jm, Langheinrich, J, Lawrence, D, Jun, Li, Lima, Acs, Livingston, K, Lu, H, Lukashin, K, Maccormick, M, Manak, Jj, Markov, N, Mcaleer, S, Mckinnon, B, Mcnabb, Jwc, Mecking, Ba, Mestayer, Md, Meyer, Ca, Mibe, T, Mikhailov, K, Minehart, R, Mirazita, Marco, Miskimen, R, Mokeev, V, Morand, L, Morrow, Sa, Moteabbed, M, Mueller, J, Mutchler, Gs, Nadel Turonski, P, Napolitano, J, Nasseripour, R, Niccolai, S, Niculescu, G, Niculescu, I, Niczyporuk, Bb, Niroula, Mr, Nyazov, Ra, Nozar, M, O'Rielly, Gv, Osipenko, Mikhail, Ostrovidov, Ai, Park, K, Pasyuk, E, Paterson, C, Philips, Sa, Pierce, J, Pivnyuk, N, Pocanic, D, Pogorelko, O, Polli, Ermanno, Pozdniakov, S, Preedom, Bm, Price, Jw, Protopopescu, D, Qin, Lm, Raue, Ba, Riccardi, G, Ricco, Giovanni, Ripani, Marco, Ritchie, Bg, Ronchetti, Federico, Rosner, G, Rossi, Patrizia, Rowntree, D, Rubin, Pd, Sabatie, E, Salgado Lopez Carlos Alberto, Santoro, Joseph, Sapunenko, Vladimir, Schumacher, Ra, Serov, Vs, Sharabian, Yg, Shaw, J, Shvedunov, Nv, Skabelin, Av, Smith, Es, Smith, Lc, Sober, Di, Stavinsky, A, Stepanyan, Ss, Stepanyan, S, Stokes, Be, Stoler, P, Strakovsky, Ii, Strauch, S, Suleiman, R, Taiuti, MAURO GINO, Taylor, S, Tedeschi, Dj, Thoma, U, Thompson, R, Tkabladze, A, Tkachenko, S, Todor, L, Tur, C, Ungaro, M, Vineyard, Mf, Vlassov, Av, Weinstein, Lb, Weygand, Dp, Williams Meurig Crispin Stowe, Wolin, E, Wood, Mh, Yegneswaran, A, Yun, J, Zana, L, Zhang, J, Zhao, B, Zhao, Z., Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CLAS, and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)
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DEEP-INELASTIC-SCATTERING ,Spin structure functions ,QUARK ,FOS: Physical sciences ,13.60.Hb ,13.88.+e ,14.20.Dh ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,PROTON ,SUM-RULE ,NEUTRON SPIN STRUCTURE ,Nucleon structure ,G(1)(N) ,CLAS ,PION ,DISTRIBUTIONS ,High Energy Physics::Experiment ,Nuclear Experiment (nucl-ex) ,NEUTRON SPIN STRUCTURE, DEEP-INELASTIC-SCATTERING, SUM-RULE, PROTON, DISTRIBUTIONS, G(1)(N), QUARK, CLAS, PION ,Nuclear Experiment - Abstract
We report results for the virtual photon asymmetry $A_1$ on the nucleon from new Jefferson Lab measurements. The experiment, which used the CEBAF Large Acceptance Spectrometer and longitudinally polarized proton ($^{15}$NH$_3$) and deuteron ($^{15}$ND$_3$) targets, collected data with a longitudinally polarized electron beam at energies between 1.6 GeV and 5.7 GeV. In the present paper, we concentrate on our results for $A_1(x,Q^2)$ and the related ratio $g_1/F_1(x,Q^2)$ in the resonance and the deep inelastic regions for our lowest and highest beam energies, covering a range in momentum transfer $Q^2$ from 0.05 to 5.0 GeV$^2$ and in final-state invariant mass $W$ up to about 3 GeV. Our data show detailed structure in the resonance region, which leads to a strong $Q^2$--dependence of $A_1(x,Q^2)$ for $W$ below 2 GeV. At higher $W$, a smooth approach to the scaling limit, established by earlier experiments, can be seen, but $A_1(x,Q^2)$ is not strictly $Q^2$--independent. We add significantly to the world data set at high $x$, up to $x = 0.6$. Our data exceed the SU(6)-symmetric quark model expectation for both the proton and the deuteron while being consistent with a negative $d$-quark polarization up to our highest $x$. This data setshould improve next-to-leading order (NLO) pQCD fits of the parton polarization distributions., Comment: 7 pages LaTeX, 5 figures
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