Study of Radiative-Correction Uncertainties in MUSE with ESEPP*

The MUon Scattering Experiment (MUSE) at Paul Scherrer Institute (PSI) intends to measure the proton charge radius from elastic electron-proton and muon-proton scattering data with positively and negatively charged beams in a four-momentum-transfer range from 0.002 to 0.08 GeV². The data will test possible differences between the electron and muon interactions and two-photon exchange effects. Radiative corrections, which depend on detector properties, are essential to reduce uncertainties in the proton radius extraction. In this talk, the effects of using a downstream photon calorimeter on the radiative corrections are studied. Based on the ESEPP (Elastic Scattering of Electrons and Positrons on Protons) event generator, the size of radiative corrections for electron and muon scattering and their uncertainties were determined and will be discussed.