Semi-inclusive π0 target and beam-target asymmetries from 6 GeV electron scattering with CLAS

We present precision measurements of the target and beam-target spin asymmetries from neutral pion electroproduction in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. We scattered 6-GeV, longitudinally polarized electrons off longitudinally polarized protons in a cryogenic (14)NH(3)target, and extracted double and single target spin asymmetries for ep -> e'pi(0)Xin multidimensional bins in four-momentum transfer (1.0 < Q(2) < 3.2GeV(2)), Bjorken-x(0.12 < x < 0.48), hadron energy fraction (0.4 < z < 0.7), transverse pion momentum (0 < P-T < 1.0GeV), and azimuthal angel phi(h) between the lepton scattering and hadron production planes. We extracted asymmetries as a function of both xand P-T, which provide access to transverse-momentum distributions of longitudinally polarized quarks. The double spin asymmetries depend weakly on P-T. The sin2 phi(h) moments are zero within uncertainties, which is consistent with the expected suppression of the Collins fragmentation function. The observed sin phi(h) moments suggest that quark gluon correlations are significant at large x. (C) 2018 The Authors. Published by Elsevier B.V.