Beam-target double-spin asymmetry A <inf>LT</inf> in charged pion production from deep inelastic scattering on a transversely polarized He3 target at 1.4<Q2<2.7GeV2

Abstract

We report the first measurement of the double-spin asymmetry A LT for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized He3 target. The kinematics focused on the valence quark region, 0.16<x<0.35 with 1.4<Q2<2.7GeV2. The corresponding neutron A LT asymmetries were extracted from the measured He3 asymmetries and proton over He3 cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function g1Tq and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for π - production on He3 and the neutron, while our π + asymmetries are consistent with zero. © 2012 American Physical Society.