Angular distributions in pion-nucleon Drell-Yan process

Abstract

We study the Drell-Yan process in the polarized pion-nucleon scattering. We calculate the $U(1{)}_{\text{em}}$ gauge invariant hadron tensors. To this end, we have to take into account two diagrams---the standard diagram and an additional one---both diagrams are required to get the gauge invariant hadron tensor. We obtain a new single transverse spin asymmetry that probes gluon poles and chiral-odd distribution functions. The process of pion-nucleon scattering in the limit of large Feynman $x$ is described by a convolution of two non-collinear exclusive-channel distribution amplitudes, which demonstrates the duality between different factorization regimes.

Comments: 6 pages, 3 figures. Contribution to the proceedings of XVII Workshop on High Energy Spin Physics (DSPIN-17), September 11-15, Dubna, Russia