Session B12: Invited Session: Longitudinal and Transverse Structure of the Nucleon

Measurement of Single/Double Target-Spin Asymmetry in Semi-Inclusive Pion Electroproduction on a Transversely Polarized $^3$He Target

Measuring parton distribution functions (PDF) which represent the flavor and spin structure of nucleon is important to reveal the information of quantum chromodynamics in the confinement region. In particular, in parton model, the cross-section in the semi-inclusive deep inelastic scattering (SIDIS), can be written as the product of PDF and fragmentation function which describe the parton hadronized process due to color force. The JLab experiment E06-010 is focusing on measuring the target single/double spin asymmetry in the semi-inclusive deep inelastic $\overrightarrow{^{3}\rm He}(e,e'\pi^{+,-})X$ reaction with a transversely polarized $^3\rm He$ target at JLab Hall A with a 5.89 GeV electron beam. The leading pions and scattered electrons were detected in coincidence by the left High-Resolution Spectrometers ($HRS_L$) at $16^{\circ}$ and BigBite spectrometer at $30^{\circ}$, respectively. Kinematic coverage was focused on the valence quark region, x $\sim$0.1-0.4, at $Q^2$ $\sim$ 1-3 (GeV/c)$^2$. The Collins, Sivers and $g_{1T}$ asymmetries of $^3\rm He$ and neutron were extracted. The overview of the experiment and results will be presented. Furthermore, the 12 GeV program with SoLID spectrometer and future possibilities at an EIC will be briefly introduced.   

Spin Structure Functions of the Proton - SANE experiment

The Spin Asymmetries of the Nucleon Experiment (SANE) is a measurement of inclusive electron scattering parallel and near perpendicular double spin asymmetries from a proton target. The main goal of the experiment was to measure $A_\parallel$ and $A_{80}$ and to extract the spin asymmetries of the proton $A_1^p,$ $A_2^p$ and the spin structure functions $g_1^p$ and $g_2^p$. Using the Thomas Jefferson National Accelerator Facility's polarized electron beam and the University of Virginia's polarized frozen ammonia ($^{14}$NH$_3$) target in Hall C, the experiment ran in 2009, collecting data in a Q$^2$ region from 2.5 to 6.5 GeV$^2$ and between Bjorken $x$ of 0.3 and 0.8. Particle detection was accomplished using the Big Electron Telescope Array (BETA), a novel non-magnetic detector. The physics motivation for the experiment and a brief overview of the polarized target and the detector will be presented along with the analysis developed in order to extract the proton spin asymmetries and structure functions. Results will be presented.   

Recent theory developments in the spin structure of the nucleon

The spin structure of the nucleon will be briefly discussed with a focus on recent developments on the theory side. The talk deals with parton helicity distributions, GPDs and TMDs, quark-gluon-quark correlations, as well as the longitudinal spin sum rule of the nucleon. Important remaining issues in this field will also be addressed.