Monte Carlo studies of photon production in polarized proton-proton collisions

We present first results obtained with a polarized version of the PYTHIA code, describing high-energy polarized hadron-hadron reactions. Such reactions are of great theoretical and experimental interest, as they give additional information on the internal spin structure of the hadrons, complementary to what can be obtained from polarized lepton-nucleon scattering. Experiments of this kind are under consideration both for the fixed target and for the collider mode. We demonstrate that corrections like e.g. showering influence the obtained asymmetries and enter the theoretical analyses necessary to deduce physically interesting quantities from the data. We also discuss the dominant background mechanisms, namely pion decay. We conclude that to determine the physics one can deduce from any kind of experimental setup a full-fledged numerical simulation is needed, towards which our present code is the first step. (orig.)