Measurement of the proton spin structure function g₁(x,Q²) for Q² from 0.15 to 1.6 GeV² with CLAS

Fatemi, R. et al. (2003) Measurement of the proton spin structure function g₁(x,Q²) for Q² from 0.15 to 1.6 GeV² with CLAS. Physical Review Letters, 91(22), (doi: 10.1103/PhysRevLett.91.222002)

Abstract

Double-polarization asymmetries for inclusive ep scattering were measured at Jefferson Lab using 2.6 and 4.3 GeV longitudinally polarized electrons incident on a longitudinally polarized NH3 target in the CLAS detector. The polarized structure function g(1)(x,Q(2)) was extracted throughout the nucleon resonance region and into the deep inelastic regime, for Q(2)=0.15-1.64 GeV2. The contributions to the first moment Gamma(1)(Q(2))=integralg(1)(x,Q(2)) dx were determined up to Q(2)=1.2 GeV2. Using a parametrization for g(1) in the unmeasured low x regions, the complete first moment was estimated over this Q(2) region. A rapid change in Gamma(1) is observed for Q(2) lt 1 GeV2, with a sign change near Q(2)=0.3 GeV2, indicating dominant contributions from the resonance region. At Q(2)=1.2 GeV2 our data are below the perturbative QCD evolved scaling value.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Branford, Prof Derek and Livingston, Dr Kenneth and Protopopescu, Dr Dan and Kellie, Dr James
• Authors: Fatemi, R., Skabelin, A.V., Burkert, V.D., Crabb, D., Vita, R.D., Kuhn, S.E., Minehart, R., Adams, G., Anciant, E., Anghinolfi, M., Asavapibhop, B.,, Audit, G., Auger, T., Avakian, H., Bagdasaryan, H., Ball, J.P., Barrow, S., Battaglieri, M., Beard, K., Bektasoglu, M., Bellis, M., Bertozzi, W., Bianchi, N., Biselli, A.S., Boiarinov, S., Bonner, B.E., Bosted, P.E., Bouchigny, S., Bradford, R., Branford, D., Brooks, W.K., Butuceanu, C., Calarco, J.R., Carman, D.,S.,, Carnahan, B., Cetina, C., Ciciani, L., Clark, R., Cole, P.L., Coleman, A.,, Connelly, J., Cords, D., Corvisiero, P., Crannell, H., Cummings, J.P., De Sanctis, E., Degtyarenko, P.V., Denizli, H., Dennis, L., Dharmawardane, K.V., Dhuga, K.S., Djalali, C., Dodge, G.E., Doughty, D., Dragovitsch, P., Dugger, M., Dytman, S., Eckhause, M., Egiyan, H., Egiyan, K.S., Elouadrhiri, L., Empl, A., Eugenio, P., Farhi, L., Feuerbach, R.J., Freyberger, A., Ficenec, J., Forest, T.A., Frolov, V., Funsten, H., Gaff, S.J., Garcon, M., Gavalian, G., Gilad, S., Gilfoyle, G.P., Giovanetti, K.L., Girard, P., Gordon, C.I.O., Griffioen, K.A., Guidal, M., Guillo, M., Guo, L., Gyurjyan, V., Hadjidakis, C., Hancock, D., Hardie, J., Heddle, D., Heimberg, P., Hersman, F.W., Hicks, K., Hicks, R.S., Holtrop, M., Hu, J., Hyde-Wright, C.E., Ilieva, Y., Ito, M.M., Jenkins, D., Joo, K., Keith, C., Kelley, J.H., Kellie, J.D., Khandaker, M., Kim, K.Y., Kim, K., Kim, W., Klein, A., Klein, F.J., Klimenko, A.V., Klusman, M., Kossov, M., Koubarovski, V., Kramer, L.H., Kuang, Y., Kuhn, J., Lachniet, J., Laget, J.M., Lawrence, D., Li, J., Livingston, K., Longhi, A., Lukashin, K., Major, W., Manak, J.J., Marchand, C., McAleer, S., McNabb, J.W.C., Mecking, B.A., Mehrabyan, S., Mestayer, M.D., Meyer, C.A., Mikhailov, K., Mirazita, M., Miskimen, R., Morand, L., Morrow, S.A., Muccifora, V., Mueller, J., Mutchler, G.S., Napolitano, J., Nasseripour, R., Nelson, S.O., Niccolai, S., Niculescu, G., Niculescu, I., Niczyporuk, B.B., Niyazov, R.A., Nozar, M., O'Brien, J.T., O'Rielly, G.V., Osipenko, M., Park, K., Pasyuk, E., Peterson, G., Pivnyuk, N., Pocanic, D., Pogorelko, O., Polli, E., Pozdniakov, S., Preedom, B.M., Price, J.W., Prok, Y., Protopopescu, D., Qin, L.M., Raue, B.A., Riccardi, G., Ricco, G., Ripani, M., Ritchie, B.G., Rock, S.E., Ronchetti, F., Rossi, P., Rowntree, D., Rubin, P.D., Sabatie, F., Sabourov, K., Salgado, C., Santoro, J.P., Sapunenko, V., Sargsyan, M., Schumacher, R.A., Seely, M., Serov, V.S., Sharabian, Y.G., Shaw, J., Simionatto, S., Smith, E.S., Smith, T., Smith, L.C., Sober, D.I., Sorrel, L., Spraker, M., Stavinsky, A., Stepanyan, S., Stoler, P., Strauch, S., Taiuti, M., Taylor, S., Tedeschi, D.J., Thoma, U., Thompson, R., Todor, L., Tur, C., Ungaro, M., Vineyard, M.F., Vlassov, A.V., Wang, K., Weinstein, L.B., Weller, H., Weygand, D.P., Whisnant, C.S., Wolin, E., Wood, M.H., Yegneswaran, A., Yun, J., Zhang, B., Zhao, J., and Zhou, Z.
• Subjects: Q Science > QC Physics
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Physical Review Letters
• Publisher: American Physical Society
• ISSN: 0031-9007
• ISSN (Online): 1079-7114