Monte Carlo simulation studies of background contributions in the Mu2e experiment

The Mu2e experiment is currently being constructed at Fermilab to search for the direct conversion of muons into electrons in the field of a nucleus without the emission of neutrinos. The experiment aims at a sensitivity of four orders of magnitude higher than previous related experiments, which implies highly demanding accuracy requirements both in the design and during the operation. Hence, it is essential to estimate precisely the backgrounds that could mimic the monoenergetic conversion electron signal and the particle yields relevant to the experiment sensitivity. In that regard, Monte Carlo simulations were performed to investigate key yields and beam-related and cosmic rays-related backgrounds. The investigation includes: (I) an evaluation of the antiproton and charged pion yields from an 8 GeV proton pencil beam impinging on a tungsten cylindrical target, (II) an evaluation of the transmission of cosmic neutrons and neutral kaons in a block of concrete. The simulations were performed using the FLUKA2021, MCNP6, GEANT4, PHITS, and MARS15 codes. The presentation will show the simulation results with a focus on the prediction obtained from each code and their impact on the experiment.