An Update to E12-11-007 Asymmetries in Semi-Inclusive Deep-Inelastic (e, e′π±) Reactions on a Longitudinally Polarized 3He Target at 8.8 and 11 GeV

This is an update for E12-11-0071, which was approved by PAC 37 in Jan 2011. E12-11-007 will measure single-target and double spin azimuthal asymmetries (SSAs and DSAs) in semi-inclusive electroproduction of charged pions using the upgraded CEBAF electron beam, a longitudinally polarized 3He target as an effective polarized neutron target, and the recently approved SoLID (Solenoidal Large Intensity Device) spectrometer [1]. We also request a high beam polarization for both this experiment and E12-10-006. The SSAs and DSAs, with longitudinal and transverse target spin, respectively, are related to two T-even “worm-gear” transverse-momentum-dependent parton distributions (TMD) of the nucleon at leading twist. Both of the “worm-gear” TMD, g1T (or transversal helicity) and h1L (or longitudinal transversity), require an interference between wave function components that differ by one unit of quark orbital angular momentum (OAM) as explicitly shown in several models. The experimental information on the “worm-gear” TMDs will be used to test Lattice QCD calculations, quark-gluon correlations and generic model assumptions of the nucleon system. In addition, the DSAs with a longitudinal target spin will constrain the flavor decomposition of the quark helicity distribution of the nucleon and provide information on their transverse momentum dependence. This experiment will provide the first data on SIDIS target-SSA with a longitudinally polarized effective neutron target. All asymmetries will be measured with a high precision and a large kinematic coverage in a 4-D phase space of x, z, Ph⊥ and Q2. The systematic uncertainties are minimized by using fast target spin flips and a large coverage in the azimuthal angles. We request 35 PAC days of beam on a longitudinally polarized 3He target. ∗ [email protected] 1 The original proposal can be found at http://www.jlab.org/exp_prog/PACpage/PAC37/proposals/Proposals/New%20Proposals/PR-11-007.pdf