The Sivers Function from SIDIS Data
  We study the Sivers effect in transverse single spin asymmetries (SSA) for pion and kaon production in Semi-Inclusive Deep Inelastic Scattering (SIDIS) processes. We perform a fit of A^{sin(phi_h-phi_S)}_UT taking into account the recent data from HERMES and COMPASS Collaborations, which allow a new determination of the Sivers distribution functions for quark and anti-quark with u, d and also s flavours. Estimates for forthcoming SIDIS experiments at COMPASS and JLab are given. 
M. Anselmino, M. Boglione, U. D'Alesio, A. Kotzinian, S. Melis, F.   Murgia, A. Prokudin, C. Turk