Single/Double-Spin Asymmetry Measurements of Semi-Inclusive Pion Electroproduction on a Transversely Polarized ^3He Target through Deep Inelastic Scattering

摘要

Parton distribution functions, which represent the flavor and spin structure of theudnucleon, provide invaluable information in illuminating quantum chromodynamics inudthe confinement region. Among various processes that measure such parton distribution functions, semi-inclusive deep inelastic scattering is regarded as one of the goldenudchannels to access transverse momentum dependent parton distribution functions, whichudprovide a 3-D view of the nucleon structure in momentum space. The Jefferson Lab ex-udperiment E06-010 focuses on measuring the target single and double spin asymmetriesudin the ^3He(e, e′π+,−)X reaction with a transversely polarized ^3He target in Hall A withuda 5.89 GeV electron beam. A leading pion and the scattered electron are detected inudcoincidence by the left High-Resolution Spectrometer at 16◦ and the BigBite spectrom-udeter at 30° beam right, respectively. The kinematic coverage concentrates in the valenceudquark region, x ∼0.1-0.4, at Q^2 ∼ 1-3 GeV^2. The Collins and Sivers asymmetries of ^3Heudand neutron are extracted. In this review, an overview of the experiment and the final results are presented. Furthermore, an upcoming 12-GeV program with a large acceptanceudsolenoidal device and the future possibilities at an electron-ion collider are discussed.