High Transverse Momentum Meson Production: A Different Way To Probe Hadron Structure

Abstract

Hard, or high transverse momentum, pion photoproduction can be a tool for probing the parton structure of the beam and target. We discuss the perturbative and soft processes that contribute, and show how regions where perturbative processes dominate can give us the parton structure information. Polarized initial states are needed to get information on polarization distributions. Current polarization asymmetry data is mostly in the soft region. However, with the proposed EPIC machine parameters, determining the polarized gluon distribution using hard pion photoproduction appears quite feasible.