Sivers effect and the single spin asymmetryANinp↑p→hXprocesses

Abstract

The single spin asymmetry ${A}_{N}$, for large ${P}_{T}$ single inclusive particle production in ${p}^{\ensuremath{\uparrow}}p$ collisions, is considered within a generalized parton model and a transverse momentum dependent factorization scheme. The focus is on the Sivers effect and the study of its potential contribution to ${A}_{N}$, based on a careful analysis of the Sivers functions extracted from azimuthal asymmetries in semi-inclusive deep inelastic scattering processes. It is found that such Sivers functions could explain most features of the ${A}_{N}$ data, including some recent STAR results which show the persistence of a nonzero ${A}_{N}$ up to surprisingly large ${P}_{T}$ values.