Sivers function: SIDIS data, fits and predictions

Abstract

The most recent data on the weighted transverse single spin asymmetry A_{UT}^{\sin(\phi_h-\phi_S)} from HERMES and COMPASS collaborations are analysed within LO parton model; all transverse motions are taken into account. Extraction of the Sivers function for u and d quarks is performed. Based on the extracted Sivers functions, predictions for A_{UT}^{\sin(\phi_h-\phi_S)} asymmetries at JLab are given; suggestions for further measurements at COMPASS, with a transversely polarized hydrogen target and selecting favourable kinematical ranges, are discussed. Predictions are also presented for Single Spin Asymmetries (SSA) in Drell-Yan processes at RHIC and GSI.

Comments: Contribution to the proceedings of "The International Workshop on Transverse Polarisation Phenomena in Hard Processes" (Transversity 2005), Como, Italy, 7-10th September 2005, talk presented by A. Prokudin, 8 pages, 10 figures