STUDY OF THE PION DISTRIBUTION AMPLITUDE IN POLARIZED MUON PAIR PRODUCTION

We consider the production of muon pairs from the scattering of pions on longitudinally polarized protons. We calculate the cross section an d the single spin asymmetry for this process, taking into account pion bound state effects. We work in the kinematic region where the photon has a large longitudinal momentum fraction, which allows us to treat the bound state problem perturbatively. Our predictions are directly p roportional to the pion distribution amplitude. A measurement of the p olarized Drell-Yan cross section, thus, allows the determination of th e shape of the pion distribution amplitude.