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The longitudinal double spin asymmetry A_LL in the reaction pp --> pi X hasbeen measured at RHIC with extremely interesting consequences. If the gluonpolarization in a proton were as big as needed to resolve the famous "spincrisis" then A_LL would be large and positive. Latest RHIC results indicatethat A_LL is small and disfavour large positive values of the gluonpolarization. We examine whether the soft mechanisms (Collins, Sivers,Boer-Mulders), essential for generating transverse single spin asymmetries,have any significant influence on A_LL, and whether they could alter theconclusion that the gluon polarization is necessarily small. It turns out thatthe contribution from these effects is essentially negligible.

Intrinsic parton motion soft mechanisms and the longitudinal spin asymmetry A_LL in high energy pp -> pi X