Results from the 2009 data of the MEG experiment in the search for μ+→e+γ

The MEG experiment is the latest in a series of progressively more precise rare decay searches designed to exploit an observation of μ + → e + γ or lack thereof as a sensitive low energy probe of new physics. A first analysis of 43 days of data acquisition in 2009 results in an upper limit of B R ( μ + → e + γ ) 1.5 × 10 − 11 (90% CL).