中国物理学会高能物理分会第十三届全国粒子物理学术会议（2021）

Studies of muon decay have helped established several parameters in the Standard Model. This decay is almost a pure weak decay and it allows for a high-precision test of the Standard Model and searches for new physics. Radiative muon decay (RMD) is particularly interesting because one of the Michel parameters, the eta parameter η, can be measured only via RMD. The branching ratio for RMD is about 5% for the photon energy above 1 MeV. However, recent measurements of RMD by PIBETA and MEG collaborations utilized muon decay at rest and only focusing on a tiny phase space of the decay. This is due to the challenges in detecting soft photons. In the Muon g-2 experiment, the relativistic gamma-factor of the muon is 29.3 and therefore a 10 MeV photon could be boosted up to 600 MeV. This opens up the possibility to measure a wider phase space of the RMD and therefore a more sensitive search for new physics that could alter the decay branching ratio. In this poster, we will present the current status of our study using Fermilab Muon g-2 experiment to measure the branching ratio of RMD.