Measurement of the x- and Q2-dependence of the asymmetry A1 on the nucleon

K. V. Dharmawardane; S. E. Kuhn; P. Bosted; Y. Prok; G. Adams; P. Ambrozewicz; M. Anghinolfi; G. Asryan; H. Avakian; H. Bagdasaryan; N. Baillie; J. P. Ball; N. A. Baltzell; S. Barrow; V. Batourine; M. Battaglieri; K. Beard; I. Bedlinskiy; M. Bektasoglu; M. Bellis; N. Benmouna; A. S. Biselli; B. E. Bonner; S. Bouchigny; S. Boiarinov; R. Bradford; D. Branford; W. K. Brooks; S. Bültmann; V. D. Burkert; C. Butuceanu; J. R. Calarco; S. L. Careccia; D. S. Carman; B. Carnahan; A. Cazes; S. Chen; P. L. Cole; P. Collins; P. Coltharp; D. Cords; P. Corvisiero; D. Crabb; H. Crannell; V. Crede; J. P. Cummings; R. De Masi; R. DeVita; E. De Sanctis; P. V. Degtyarenko; H. Denizli; L. Dennis; A. Deur; C. Djalali; G. E. Dodge; J. Donnelly; D. Doughty; P. Dragovitsch; M. Dugger; S. Dytman; O. P. Dzyubak; H. Egiyan; K. S. Egiyan; L. Elouadrhiri; P. Eugenio; R. Fatemi; G. Fedotov; R. J. Feuerbach; T. A. Forest; H. Funsten; M. Garçon; G. Gavalian; G. P. Gilfoyle; K. L. Giovanetti; F. X. Girod; J. T. Goetz; E. Golovatch; A. Gonenc; R. W. Gothe; K. A. Griffioen; M. Guidal; M. Guillo; N. Guler; L. Guo; V. Gyurjyan; C. Hadjidakis; K. Hafidi; R. S. Hakobyan; J. Hardie; D. Heddle; F. W. Hersman; K. Hicks; I. Hleiqawi; M. Holtrop; M. Huertas; C. E. Hyde-Wright; Y. Ilieva; D. G. Ireland; B. S. Ishkhanov; E. L. Isupov; M. M. Ito; D. Jenkins; H. S. Jo; K. Joo; H. G. Juengst; C. Keith; J. D. Kellie; M. Khandaker; K. Y. Kim; K. Kim; W. Kim; A. Klein; F. J. Klein; M. Klusman; M. Kossov; L. H. Kramer; V. Kubarovsky; J. Kuhn; S. V. Kuleshov; J. Lachniet; J. M. Laget; J. Langheinrich; D. Lawrence; Ji Li; A. C.S. Lima; K. Livingston; H. Lu; K. Lukashin; M. MacCormick; J. J. Manak; N. Markov; S. McAleer; B. McKinnon; J. W.C. McNabb; B. A. Mecking; M. D. Mestayer; C. A. Meyer; T. Mibe; K. Mikhailov; R. Minehart; M. Mirazita; R. Miskimen; V. Mokeev; L. Morand; S. A. Morrow; M. Moteabbed; J. Mueller; G. S. Mutchler; P. Nadel-Turonski; J. Napolitano; R. Nasseripour; S. Niccolai; G. Niculescu; I. Niculescu; B. B. Niczyporuk; M. R. Niroula; R. A. Niyazov; M. Nozar; G. V. O'Rielly; M. Osipenko; A. I. Ostrovidov; K. Park; E. Pasyuk; C. Paterson; S. A. Philips; J. Pierce; N. Pivnyuk; D. Pocanic; O. Pogorelko; E. Polli; S. Pozdniakov; B. M. Preedom; J. W. Price; D. Protopopescu; L. M. Qin; B. A. Raue; G. Riccardi; G. Ricco; M. Ripani; B. G. Ritchie; F. Ronchetti; G. Rosner; P. Rossi; D. Rowntree; P. D. Rubin; F. Sabatié; C. Salgado; J. P. Santoro; V. Sapunenko; R. A. Schumacher; V. S. Serov; Y. G. Sharabian; J. Shaw; N. V. Shvedunov; A. V. Skabelin; E. S. Smith; L. C. Smith; D. I. Sober; A. Stavinsky; S. S. Stepanyan; S. Stepanyan; B. E. Stokes; P. Stoler; I. I. Strakovsky; S. Strauch; R. Suleiman; M. Taiuti; S. Taylor; D. J. Tedeschi; U. Thoma; R. Thompson; A. Tkabladze; S. Tkachenko; L. Todor; C. Tur; M. Ungaro; M. F. Vineyard; A. V. Vlassov; L. B. Weinstein; D. P. Weygand; M. Williams; E. Wolin; M. H. Wood; A. Yegneswaran; J. Yun; L. Zana; J. Zhang; B. Zhao; Z. Zhao

doi:10.1016/j.physletb.2006.08.011

Measurement of the x- and Q²-dependence of the asymmetry A₁ on the nucleon

K. V. Dharmawardane, S. E. Kuhn, P. Bosted, Y. Prok, G. Adams, P. Ambrozewicz, M. Anghinolfi, G. Asryan, H. Avakian, H. Bagdasaryan, N. Baillie, J. P. Ball, N. A. Baltzell, S. Barrow, V. Batourine, M. Battaglieri, K. Beard, I. Bedlinskiy, M. Bektasoglu, M. BellisN. Benmouna, A. S. Biselli, B. E. Bonner, S. Bouchigny, S. Boiarinov, R. Bradford, D. Branford, W. K. Brooks, S. Bültmann, V. D. Burkert, C. Butuceanu, J. R. Calarco, S. L. Careccia, D. S. Carman, B. Carnahan, A. Cazes, S. Chen, P. L. Cole, P. Collins, P. Coltharp, D. Cords, P. Corvisiero, D. Crabb, H. Crannell, V. Crede, J. P. Cummings, R. De Masi, R. DeVita, E. De Sanctis, P. V. Degtyarenko, H. Denizli, L. Dennis, A. Deur, C. Djalali, G. E. Dodge, J. Donnelly, D. Doughty, P. Dragovitsch, M. Dugger, S. Dytman, O. P. Dzyubak, H. Egiyan, K. S. Egiyan, L. Elouadrhiri, P. Eugenio, R. Fatemi, G. Fedotov, R. J. Feuerbach, T. A. Forest, H. Funsten, M. Garçon, G. Gavalian, G. P. Gilfoyle, K. L. Giovanetti, F. X. Girod, J. T. Goetz, E. Golovatch, A. Gonenc, R. W. Gothe, K. A. Griffioen, M. Guidal, M. Guillo, N. Guler, L. Guo, V. Gyurjyan, C. Hadjidakis, K. Hafidi, R. S. Hakobyan, J. Hardie, D. Heddle, F. W. Hersman, K. Hicks, I. Hleiqawi, M. Holtrop, M. Huertas, C. E. Hyde-Wright, Y. Ilieva, D. G. Ireland, B. S. Ishkhanov, E. L. Isupov, M. M. Ito, D. Jenkins, H. S. Jo, K. Joo, H. G. Juengst, C. Keith, J. D. Kellie, M. Khandaker, K. Y. Kim, K. Kim, W. Kim, A. Klein, F. J. Klein, M. Klusman, M. Kossov, L. H. Kramer, V. Kubarovsky, J. Kuhn, S. V. Kuleshov, J. Lachniet, J. M. Laget, J. Langheinrich, D. Lawrence, Ji Li, A. C.S. Lima, K. Livingston, H. Lu, K. Lukashin, M. MacCormick, J. J. Manak, N. Markov, S. McAleer, B. McKinnon, J. W.C. McNabb, B. A. Mecking, M. D. Mestayer, C. A. Meyer, T. Mibe, K. Mikhailov, R. Minehart, M. Mirazita, R. Miskimen, V. Mokeev, L. Morand, S. A. Morrow, M. Moteabbed, J. Mueller, G. S. Mutchler, P. Nadel-Turonski, J. Napolitano, R. Nasseripour, S. Niccolai, G. Niculescu, I. Niculescu, B. B. Niczyporuk, M. R. Niroula, R. A. Niyazov, M. Nozar, G. V. O'Rielly, M. Osipenko, A. I. Ostrovidov, K. Park, E. Pasyuk, C. Paterson, S. A. Philips, J. Pierce, N. Pivnyuk, D. Pocanic, O. Pogorelko, E. Polli, S. Pozdniakov, B. M. Preedom, J. W. Price, D. Protopopescu, L. M. Qin, B. A. Raue, G. Riccardi, G. Ricco, M. Ripani, B. G. Ritchie, F. Ronchetti, G. Rosner, P. Rossi, D. Rowntree, P. D. Rubin, F. Sabatié, C. Salgado, J. P. Santoro, V. Sapunenko, R. A. Schumacher, V. S. Serov, Y. G. Sharabian, J. Shaw, N. V. Shvedunov, A. V. Skabelin, E. S. Smith, L. C. Smith, D. I. Sober, A. Stavinsky, S. S. Stepanyan, S. Stepanyan, B. E. Stokes, P. Stoler, I. I. Strakovsky, S. Strauch, R. Suleiman, M. Taiuti, S. Taylor, D. J. Tedeschi, U. Thoma, R. Thompson, A. Tkabladze, S. Tkachenko, L. Todor, C. Tur, M. Ungaro, M. F. Vineyard, A. V. Vlassov, L. B. Weinstein, D. P. Weygand, M. Williams, E. Wolin, M. H. Wood, A. Yegneswaran, J. Yun, L. Zana, J. Zhang, B. Zhao, Z. Zhao

Research output: Contribution to journal › Article › peer-review

161 Scopus citations

Abstract

We report results for the virtual photon asymmetry A₁ on the nucleon from new Jefferson Lab measurements. The experiment, which used the CEBAF Large Acceptance Spectrometer and longitudinally polarized proton (¹⁵NH₃) and deuteron (¹⁵ND₃) targets, collected data with a longitudinally polarized electron beam at energies between 1.6 GeV and 5.7 GeV. In the present Letter, we concentrate on our results for A₁ (x, Q²) and the related ratio g₁ / F₁ (x, Q²) in the resonance and the deep inelastic regions for our lowest and highest beam energies, covering a range in momentum transfer Q² from 0.05 to 5.0 (GeV / c)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 Q²-dependence of A₁ (x, Q²) for W below 2 GeV. At higher W, a smooth approach to the scaling limit, established by earlier experiments, can be seen, but A₁ (x, Q²) is not strictly Q²-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 set should improve next-to-leading order (NLO) pQCD fits of the parton polarization distributions.

Original language	English
Pages (from-to)	11-17
Number of pages	7
Journal	Physics Letters B
Volume	641
Issue number	1
DOIs	https://doi.org/10.1016/j.physletb.2006.08.011
State	Published - Sep 28 2006
Externally published	Yes

Funding

We would like to acknowledge the outstanding efforts of the staff of the Accelerator and the Physics Divisions at Jefferson Lab that made this experiment possible. This work was supported in part by the US Department of Energy and the National Science Foundation, the Italian Instituto Nazionale di Fisica Nucleare, the French Centre National de la Recherche Scientifique, the French Commissariat à l'Energie Atomique, the Emmy Noether grant from the Deutsche Forschungs Gemeinschaft and the Korean Science and Engineering Foundation. The Southeastern Universities Research Association (SURA) operates the Thomas Jefferson National Accelerator Facility for the United States Department of Energy under contract DE-AC05-84ER-40150.

Funders	Funder number
Deutsche Forschungs Gemeinschaft
Korean Science and Engineering Foundation
Southeastern Universities Research Association
US Department of Energy
National Science Foundation
Thomas Jefferson National Accelerator Facility	DE-AC05-84ER-40150
Centre Eau Terre Environnement, Institut National de la Recherche Scientifique
Instituto Nazionale di Fisica Nucleare
Commissariat à l'Énergie Atomique et aux Énergies Alternatives

Keywords

Nucleon structure
Spin structure functions

Access to Document

10.1016/j.physletb.2006.08.011

Cite this

Dharmawardane, K. V., Kuhn, S. E., Bosted, P., Prok, Y., Adams, G., Ambrozewicz, P., Anghinolfi, M., Asryan, G., Avakian, H., Bagdasaryan, H., Baillie, N., Ball, J. P., Baltzell, N. A., Barrow, S., Batourine, V., Battaglieri, M., Beard, K., Bedlinskiy, I., Bektasoglu, M., ... Zhao, Z. (2006). Measurement of the x- and Q²-dependence of the asymmetry A₁ on the nucleon. Physics Letters B, 641(1), 11-17. https://doi.org/10.1016/j.physletb.2006.08.011

@article{054ac3f708b841e490da6bfdc782ac62,

title = "Measurement of the x- and Q2-dependence of the asymmetry A1 on the nucleon",

abstract = "We report results for the virtual photon asymmetry A1 on the nucleon from new Jefferson Lab measurements. The experiment, which used the CEBAF Large Acceptance Spectrometer and longitudinally polarized proton (15NH3) and deuteron (15ND3) targets, collected data with a longitudinally polarized electron beam at energies between 1.6 GeV and 5.7 GeV. In the present Letter, we concentrate on our results for A1 (x, Q2) and the related ratio g1 / F1 (x, Q2) in the resonance and the deep inelastic regions for our lowest and highest beam energies, covering a range in momentum transfer Q2 from 0.05 to 5.0 (GeV / c)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 Q2-dependence of A1 (x, Q2) for W below 2 GeV. At higher W, a smooth approach to the scaling limit, established by earlier experiments, can be seen, but A1 (x, Q2) is not strictly Q2-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 set should improve next-to-leading order (NLO) pQCD fits of the parton polarization distributions.",

keywords = "Nucleon structure, Spin structure functions",

author = "Dharmawardane, {K. V.} and Kuhn, {S. E.} and P. Bosted and Y. Prok and G. Adams and P. Ambrozewicz and M. Anghinolfi and G. Asryan and H. Avakian and H. Bagdasaryan and N. Baillie and Ball, {J. P.} and Baltzell, {N. A.} and S. Barrow and V. Batourine and M. Battaglieri and K. Beard and I. Bedlinskiy and M. Bektasoglu and M. Bellis and N. Benmouna and Biselli, {A. S.} and Bonner, {B. E.} and S. Bouchigny and S. Boiarinov and R. Bradford and D. Branford and Brooks, {W. K.} and S. B{\"u}ltmann and Burkert, {V. D.} and C. Butuceanu and Calarco, {J. R.} and Careccia, {S. L.} and Carman, {D. S.} and B. Carnahan and A. Cazes and S. Chen and Cole, {P. L.} and P. Collins and P. Coltharp and D. Cords and P. Corvisiero and D. Crabb and H. Crannell and V. Crede and Cummings, {J. P.} and {De Masi}, R. and R. DeVita and {De Sanctis}, E. and Degtyarenko, {P. V.} and H. Denizli and L. Dennis and A. Deur and C. Djalali and Dodge, {G. E.} and J. Donnelly and D. Doughty and P. Dragovitsch and M. Dugger and S. Dytman and Dzyubak, {O. P.} and H. Egiyan and Egiyan, {K. S.} and L. Elouadrhiri and P. Eugenio and R. Fatemi and G. Fedotov and Feuerbach, {R. J.} and Forest, {T. A.} and H. Funsten and M. Gar{\c c}on and G. Gavalian and Gilfoyle, {G. P.} and Giovanetti, {K. L.} and Girod, {F. X.} and Goetz, {J. T.} and E. Golovatch and A. Gonenc and Gothe, {R. W.} and Griffioen, {K. A.} and M. Guidal and M. Guillo and N. Guler and L. Guo and V. Gyurjyan and C. Hadjidakis and K. Hafidi and Hakobyan, {R. S.} and J. Hardie and D. Heddle and Hersman, {F. W.} and K. Hicks and I. Hleiqawi and M. Holtrop and M. Huertas and Hyde-Wright, {C. E.} and Y. Ilieva and Ireland, {D. G.} and Ishkhanov, {B. S.} and Isupov, {E. L.} and Ito, {M. M.} and D. Jenkins and Jo, {H. S.} and K. Joo and Juengst, {H. G.} and C. Keith and Kellie, {J. D.} and M. Khandaker and Kim, {K. Y.} and K. Kim and W. Kim and A. Klein and Klein, {F. J.} and M. Klusman and M. Kossov and Kramer, {L. H.} and V. Kubarovsky and J. Kuhn and Kuleshov, {S. V.} and J. Lachniet and Laget, {J. M.} and J. Langheinrich and D. Lawrence and Ji Li and Lima, {A. C.S.} and K. Livingston and H. Lu and K. Lukashin and M. MacCormick and Manak, {J. J.} and N. Markov and S. McAleer and B. McKinnon and McNabb, {J. W.C.} and Mecking, {B. A.} and Mestayer, {M. D.} and Meyer, {C. A.} and T. Mibe and K. Mikhailov and R. Minehart and M. Mirazita and R. Miskimen and V. Mokeev and L. Morand and Morrow, {S. A.} and M. Moteabbed and J. Mueller and Mutchler, {G. S.} and P. Nadel-Turonski and J. Napolitano and R. Nasseripour and S. Niccolai and G. Niculescu and I. Niculescu and Niczyporuk, {B. B.} and Niroula, {M. R.} and Niyazov, {R. A.} and M. Nozar and O'Rielly, {G. V.} and M. Osipenko and Ostrovidov, {A. I.} and K. Park and E. Pasyuk and C. Paterson and Philips, {S. A.} and J. Pierce and N. Pivnyuk and D. Pocanic and O. Pogorelko and E. Polli and S. Pozdniakov and Preedom, {B. M.} and Price, {J. W.} and D. Protopopescu and Qin, {L. M.} and Raue, {B. A.} and G. Riccardi and G. Ricco and M. Ripani and Ritchie, {B. G.} and F. Ronchetti and G. Rosner and P. Rossi and D. Rowntree and Rubin, {P. D.} and F. Sabati{\'e} and C. Salgado and Santoro, {J. P.} and V. Sapunenko and Schumacher, {R. A.} and Serov, {V. S.} and Sharabian, {Y. G.} and J. Shaw and Shvedunov, {N. V.} and Skabelin, {A. V.} and Smith, {E. S.} and Smith, {L. C.} and Sober, {D. I.} and A. Stavinsky and Stepanyan, {S. S.} and S. Stepanyan and Stokes, {B. E.} and P. Stoler and Strakovsky, {I. I.} and S. Strauch and R. Suleiman and M. Taiuti and S. Taylor and Tedeschi, {D. J.} and U. Thoma and R. Thompson and A. Tkabladze and S. Tkachenko and L. Todor and C. Tur and M. Ungaro and Vineyard, {M. F.} and Vlassov, {A. V.} and Weinstein, {L. B.} and Weygand, {D. P.} and M. Williams and E. Wolin and Wood, {M. H.} and A. Yegneswaran and J. Yun and L. Zana and J. Zhang and B. Zhao and Z. Zhao",

year = "2006",

month = sep,

day = "28",

doi = "10.1016/j.physletb.2006.08.011",

language = "English",

volume = "641",

pages = "11--17",

journal = "Physics Letters B",

issn = "0370-2693",

publisher = "Elsevier",

number = "1",

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Dharmawardane, KV, Kuhn, SE, Bosted, P, Prok, Y, Adams, G, Ambrozewicz, P, Anghinolfi, M, Asryan, G, Avakian, H, Bagdasaryan, H, Baillie, N, Ball, JP, Baltzell, NA, Barrow, S, Batourine, V, Battaglieri, M, Beard, K, Bedlinskiy, I, Bektasoglu, M, Bellis, M, Benmouna, N, Biselli, AS, Bonner, BE, Bouchigny, S, Boiarinov, S, Bradford, R, Branford, D, Brooks, WK, Bültmann, S, Burkert, VD, Butuceanu, C, Calarco, JR, Careccia, SL, Carman, DS, Carnahan, B, Cazes, A, Chen, S, Cole, PL, Collins, P, Coltharp, P, Cords, D, Corvisiero, P, Crabb, D, Crannell, H, Crede, V, Cummings, JP, De Masi, R, DeVita, R, De Sanctis, E, Degtyarenko, PV, Denizli, H, Dennis, L, Deur, A, Djalali, C, Dodge, GE, Donnelly, J, Doughty, D, Dragovitsch, 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, Garçon, M, Gavalian, G, Gilfoyle, GP, Giovanetti, KL, Girod, FX, Goetz, JT, Golovatch, E, Gonenc, A, Gothe, RW, Griffioen, KA, Guidal, M, Guillo, M, Guler, N, Guo, L, Gyurjyan, V, Hadjidakis, C, Hafidi, K, Hakobyan, RS, Hardie, J, Heddle, D, Hersman, FW, Hicks, K, Hleiqawi, I, Holtrop, M, Huertas, M, Hyde-Wright, 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, Li, J, 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, M, 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, Niyazov, RA, Nozar, M, O'Rielly, GV, Osipenko, M, Ostrovidov, AI, Park, K, Pasyuk, E, Paterson, C, Philips, SA, Pierce, J, Pivnyuk, N, Pocanic, D, Pogorelko, O, Polli, E, Pozdniakov, S, Preedom, BM, Price, JW, Protopopescu, D, Qin, LM, Raue, BA, Riccardi, G, Ricco, G, Ripani, M, Ritchie, BG, Ronchetti, F, Rosner, G, Rossi, P, Rowntree, D, Rubin, PD, Sabatié, F, Salgado, C, Santoro, JP, Sapunenko, V, 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, M, 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, M, Wolin, E, Wood, MH, Yegneswaran, A, Yun, J, Zana, L, Zhang, J, Zhao, B & Zhao, Z 2006, 'Measurement of the x- and Q²-dependence of the asymmetry A₁ on the nucleon', Physics Letters B, vol. 641, no. 1, pp. 11-17. https://doi.org/10.1016/j.physletb.2006.08.011

TY - JOUR

T1 - Measurement of the x- and Q2-dependence of the asymmetry A1 on the nucleon

AU - Dharmawardane, K. V.

AU - Kuhn, S. E.

AU - Bosted, P.

AU - Prok, Y.

AU - Adams, G.

AU - Ambrozewicz, P.

AU - Anghinolfi, M.

AU - Asryan, G.

AU - Avakian, H.

AU - Bagdasaryan, H.

AU - Baillie, N.

AU - Ball, J. P.

AU - Baltzell, N. A.

AU - Barrow, S.

AU - Batourine, V.

AU - Battaglieri, M.

AU - Beard, K.

AU - Bedlinskiy, I.

AU - Bektasoglu, M.

AU - Bellis, M.

AU - Benmouna, N.

AU - Biselli, A. S.

AU - Bonner, B. E.

AU - Bouchigny, S.

AU - Boiarinov, S.

AU - Bradford, R.

AU - Branford, D.

AU - Brooks, W. K.

AU - Bültmann, S.

AU - Burkert, V. D.

AU - Butuceanu, C.

AU - Calarco, J. R.

AU - Careccia, S. L.

AU - Carman, D. S.

AU - Carnahan, B.

AU - Cazes, A.

AU - Chen, S.

AU - Cole, P. L.

AU - Collins, P.

AU - Coltharp, P.

AU - Cords, D.

AU - Corvisiero, P.

AU - Crabb, D.

AU - Crannell, H.

AU - Crede, V.

AU - Cummings, J. P.

AU - De Masi, R.

AU - DeVita, R.

AU - De Sanctis, E.

AU - Degtyarenko, P. V.

AU - Denizli, H.

AU - Dennis, L.

AU - Deur, A.

AU - Djalali, C.

AU - Dodge, G. E.

AU - Donnelly, J.

AU - Doughty, D.

AU - Dragovitsch, P.

AU - Dugger, M.

AU - Dytman, S.

AU - Dzyubak, O. P.

AU - Egiyan, H.

AU - Egiyan, K. S.

AU - Elouadrhiri, L.

AU - Eugenio, P.

AU - Fatemi, R.

AU - Fedotov, G.

AU - Feuerbach, R. J.

AU - Forest, T. A.

AU - Funsten, H.

AU - Garçon, M.

AU - Gavalian, G.

AU - Gilfoyle, G. P.

AU - Giovanetti, K. L.

AU - Girod, F. X.

AU - Goetz, J. T.

AU - Golovatch, E.

AU - Gonenc, A.

AU - Gothe, R. W.

AU - Griffioen, K. A.

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PY - 2006/9/28

Y1 - 2006/9/28

N2 - We report results for the virtual photon asymmetry A1 on the nucleon from new Jefferson Lab measurements. The experiment, which used the CEBAF Large Acceptance Spectrometer and longitudinally polarized proton (15NH3) and deuteron (15ND3) targets, collected data with a longitudinally polarized electron beam at energies between 1.6 GeV and 5.7 GeV. In the present Letter, we concentrate on our results for A1 (x, Q2) and the related ratio g1 / F1 (x, Q2) in the resonance and the deep inelastic regions for our lowest and highest beam energies, covering a range in momentum transfer Q2 from 0.05 to 5.0 (GeV / c)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 Q2-dependence of A1 (x, Q2) for W below 2 GeV. At higher W, a smooth approach to the scaling limit, established by earlier experiments, can be seen, but A1 (x, Q2) is not strictly Q2-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 set should improve next-to-leading order (NLO) pQCD fits of the parton polarization distributions.

AB - We report results for the virtual photon asymmetry A1 on the nucleon from new Jefferson Lab measurements. The experiment, which used the CEBAF Large Acceptance Spectrometer and longitudinally polarized proton (15NH3) and deuteron (15ND3) targets, collected data with a longitudinally polarized electron beam at energies between 1.6 GeV and 5.7 GeV. In the present Letter, we concentrate on our results for A1 (x, Q2) and the related ratio g1 / F1 (x, Q2) in the resonance and the deep inelastic regions for our lowest and highest beam energies, covering a range in momentum transfer Q2 from 0.05 to 5.0 (GeV / c)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 Q2-dependence of A1 (x, Q2) for W below 2 GeV. At higher W, a smooth approach to the scaling limit, established by earlier experiments, can be seen, but A1 (x, Q2) is not strictly Q2-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 set should improve next-to-leading order (NLO) pQCD fits of the parton polarization distributions.

KW - Nucleon structure

KW - Spin structure functions

UR - http://www.scopus.com/inward/record.url?scp=33748468962&partnerID=8YFLogxK

U2 - 10.1016/j.physletb.2006.08.011

DO - 10.1016/j.physletb.2006.08.011

M3 - Article

AN - SCOPUS:33748468962

SN - 0370-2693

VL - 641

SP - 11

EP - 17

JO - Physics Letters B

JF - Physics Letters B

IS - 1

ER -