Sivers and Collins Effects: from SIDIS to Proton-Proton Inclusive Pion Production

Abstract

We consider the Sivers, Collins and transversity functions as extracted from SIDIS and e+e- experimental data and investigate to what extent they might explain the large Single Spin Asymmetries (SSA) observed in proton-proton inclusive processes. This phenomenological study is performed within the TMD factorization scheme. As the SIDIS data cover only a limited range of x values (x < 0.3), we allow for different large $x$ behaviours of the SIDIS Sivers functions and transversity distributions. We conclude that, within the available experimental constraints, one cannot observe any clear universality breaking effect for the Sivers functions.

Talk by M. Boglione at the "XVII International Workshop on Deep-Inelastic Scattering and Related subjects", DIS 2009, 26-30 April 2009, Madrid, Spain