The OLYMPUS radiative ep generator

The OLYMPUS experiment at DESY has collected datasets with positrons and electrons incident on hydrogen which, in combination, allow a precise determination of the contribution of hard two-photon exchange to elastic ep scattering. This radiative correction could explain the discrepancy between measurements using Rosenbluth separation and those using polarization techniques of the proton form factor ratio G_E/G_M. Additional radiative corrections to the final result need to be carefully taken into account as they may be larger than hard two-photon exchange itself. As some radiative corrections are sensitive to detector acceptances, resolutions, and analysis cuts, a radiative generator for use with the OLYMPUS Geant4 Monte Carlo has been developed. This generator includes full elastic corrections and an exact calculation of first order bremsstrahlung. A general description of the generator, its special features, and its usage in the OLYMPUS analysis will be presented.