Double spin asymmetry ALT in direct photon production

Abstract

We study the longitudinal-transverse double spin asymmetry A(LT) for direct photon production in nucleon-nucleon scattering by using the collinear twist-3 approach. This asymmetry, which, for instance, could be measured at RHIC, contains a complete set of collinear twist-3 correlation functions in a transversely polarized nucleon. (C) 2012 Published by Elsevier B.V.