Single spin asymmetries in lp→hX processes: A test of factorization

Predictions for the transverse single spin asymmetry (SSA), AN, are given for the inclusive processes lp^↑→hX and lp ^↑→jet+X, which could be measured in operating or future experiments. These estimates are based on the Sivers distributions and the Collins fragmentation functions which fit the azimuthal asymmetries measured in semi-inclusive deep inelastic scattering (SIDIS) processes (lp ^↑→l′hX). The factorization in terms of transverse momentum dependent distribution and fragmentation functions (TMD factorization)-which supplies the theoretical framework in which SIDIS azimuthal asymmetries are analyzed-is assumed to hold also for the lp→hX inclusive process at large PT. A measurement of AN would then provide a direct test of the validity of the TMD factorization in this case and would have important consequences for the study and understanding of SSAs in pp ^↑→hX processes.