Longitudinal double-spin asymmetries in semi-inclusive deep-inelastic scattering of electrons and positrons by protons and deuterons
A. Airapetian (II. Physikalisches Institut, Justus-Liebig Universität Gießen, 35392 Gießen, Germany, Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040, USA); N. Akopov (Yerevan Physics Institute, 375036 Yerevan, Armenia); Z. Akopov (DESY, 22603 Hamburg, Germany); E. C. Aschenauer (DESY, 15738 Zeuthen, Germany); W. Augustyniak (National Centre for Nuclear Research, 00-689 Warsaw, Poland); et al - Show all 98 authors
A comprehensive collection of results on longitudinal double-spin asymmetries is presented for charged pions and kaons produced in semi-inclusive deep-inelastic scattering of electrons and positrons on the proton and deuteron, based on the full HERMES data set. The dependence of the asymmetries on hadron transverse momentum and azimuthal angle extends the sensitivity to the flavor structure of the nucleon beyond the distribution functions accessible in the collinear framework. No strong dependence on those variables is observed. In addition, the hadron charge-difference asymmetry is presented, which under certain model assumptions provides access to the helicity distributions of valence quarks.
