The Role of Lepton Mass in QED Corrections for Muon Scattering on a Nucleon.*

In order to address the proton radius puzzle through measuring the muon-proton and electron-proton elastic cross sections in the same experiment (MUSE), QED corrections have to be taken into account. In this talk, we will report both kinematic and dynamical sources of the differences between muon-nucleon and electron-nucleon elastic scattering. In addition, single-spin asymmetries caused by muon beam polarization will be shown to affect the scattering cross section at 0.1 per cent level. Novel effects due to the lepton mass are incorporated into a Monte-Carlo code ELRADGEN.