Proton spin structure in the resonance region.
/ Authors
F. Wesselmann, K. Slifer, S. Tajima, A. Aghalaryan, A. Ahmidouch, R. Asaturyan, F. Bloch, W. Boeglin, P. Bosted, C. Carasco
and 62 more authors
R. Carlini, J. Cha, J. Chen, M. Christy, L. Cole, L. Coman, D. Crabb, S. Danagoulian, D. Day, J. Dunne, M. Elaasar, R. Ent, H. Fenker, E. Frlež, L. Gan, D. Gaskell, J. Gomez, B. Hu, M. Jones, J. Jourdan, C. Keith, C. Keppel, M. Khandaker, A. Klein, L. Kramer, Y. Liang, J. Lichtenstadt, R. Lindgren, D. Mack, P. McKee, D. Mcnulty, D. Meekins, H. Mkrtchyan, R. Nasseripour, I. Niculescu, K. Normand, B. Norum, D. Počanić, Y. Prok, B. Raue, J. Reinhold, J. Roche, D. Rohe, O. Rondon, N. Savvinov, B. Sawatzky, M. Seely, I. Sick, C. Smith, G. Smith, S. Stepanyan, L. Tang, G. Testa, W. Vulcan, K. Wang, G. Warren, S. Wood, C. Yan, L. Yuan, J. Yun, M. Zeier, H. Zhu
/ Abstract
We have examined the spin structure of the proton in the region of the nucleon resonances (1.085 GeV<W<1.910 GeV) at an average four momentum transfer of Q2=1.3 GeV2. Using the Jefferson Lab polarized electron beam, a spectrometer, and a polarized solid target, we measured the asymmetries A|| and A(perpendicular) to high precision, and extracted the asymmetries A1 and A2, and the spin structure functions g1 and g2. We found a notably nonzero A(perpendicular), significant contributions from higher-twist effects, and only weak support for polarized quark-hadron duality.
Journal: Physical review letters