Fully differential NLO predictions for the rare muon decay

Abstract

Using the automation program GoSam, fully differential NLO corrections were obtained for the rare decay of the muon μ→eνν¯ee. This process is an important Standard Model background to searches of the Mu3e Collaboration for lepton-flavor violation, as it becomes indistinguishable from the signal μ→3e if the neutrinos carry little energy. With our NLO program we are able to compute the branching ratio as well as custom-tailored observables for the experiment. With minor modifications, related decays of the tau can also be computed.