Single Spin Asymmetries in Charged Pion Production from Semi-Inclusive Deep Inelastic Scattering on a Transversely Polarized 3He Target at Q2=1.4–2.7 GeV2

Abstract

We report the first measurement of target single spin asymmetries in the semi-inclusive [superscript 3]He(e,e[superscript ′]π[superscript ±])X reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.16<x<0.35 with 1.4<Q[superscript 2]<2.7 GeV[superscript 2]. The Collins and Sivers moments were extracted from the azimuthal angular dependence of the measured asymmetries. The π[superscript ±] Collins moments for [superscript 3]He are consistent with zero, except for the π[superscript +] moment at x=0.35, which deviates from zero by 2.3σ. While the π[superscript -] Sivers moments are consistent with zero, the π[superscript +] Sivers moments favor negative values. The neutron results were extracted using the nucleon effective polarization and measured cross section ratios of proton to [superscript 3]He, and are largely consistent with the predictions of phenomenological fits and quark model calculations.