Single spin asymmetries in l p --> h X processes: a test of factorization

Predictions for the transverse single spin asymmetry (SSA), A(N), are given for the inclusive processes l p(uparrow) -> hX and l p(up arrow) -> 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 (l p(uparrow -> l' h X). 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 P(T). A measurement of A(N) 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 p p(uparrow) -> h X processes.