Semi-inclusive DIS Experiments Using Transversely Polarized Targets in Hall-A: Current Results and Future Plans

Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA

^a e-mail: kalyan@jlab.org

Abstract

Measurement of single (SSA) and double spin asymmetries (DSA) in semiinclusive DIS reactions using polarized targets provide a powerful method to probe transverse momentum dependent parton distribution functions (TMDs). In particular, the experimentally measured SSA on nucleon targets can help in extracting the transversity and Sivers distribution functions of u and d-quarks. Similarly, the measured DSA are sensitive to the quark spin-orbital correlations, and provide an access to the TMD parton distribution function (g_1T). A recent experiment conducted in Hall-A Jefferson Lab using transversely polarized ³He provide first such measurements on “effective” neutron target. The measurement was performed using 5.9 GeV beam from CEBAF and measured the target SSA/DSA in the SIDIS reaction ³He^↑(e, e′π^±)X. The kinematical range, x = 0.19 ~ 0.34, at Q² = 1.77 ~ 2.73 (GeV/c)², was focused on the valence quark region. The results from this measurement along with our plans for future high precision measurements in Hall-A are presented.