The Monte Carlo simulation for the MUSE experiment

The proton radius puzzle comes from the discrepancy of the proton radius measured by hydrogen spectroscopy and scattering and e or µ particles interacting with the hydrogen. The MUSE experiment at the Paul Scherer Institute uses a mixed secondary beam (e, µ , π) with momenta of 115, 160, or 210 MeV/c to measure ep and µp scattering at the same time. This will allow MUSE to address the proton radius puzzle and compare ep and µp with reduced systematic uncertainties, which should provide a better test of lepton universality than has been seen before experimentally. In order to apply appropriate corrections and better understand the experimental data including various background contributions, a simulation is needed. In the MUSE experiment, a geant4-based Monte Carlo simulation has been developed called g4PSI. Challenges in the MUSE simulation that are being overcome include the secondary mixed beam, requiring the simulation of the incident beam and scattered track, and radiative effects in the scattering process also need to be accounted for that are not included in the standard geant4 software. This talk will present the current status of the MUSE Monte Carlo simulation.