Search for the decay μ → eγ in the MEG experiment

The MEG experiment is currently searching for the lepton-flavor-changing decay μ → eγ. The Standard Model implies the μ → eγ by neutrino oscillations but it cannot be observed in experiments because of too small branching ratio. Many extensions of the Standard Model, however, predict the decay within a reach of the MEG experiment and it is a clear evidence of new physics. A liquid xenon gamma-ray detector and a positron spectrometer with a gradient magnetic field enables better sensitivity than the current limit by two orders of magnitude. The physics data taking started in 2008 and then upgrades of the detector brought a stable operation in 2009-year run. We report the preliminary result on the 2009 data together with a current status and a future of the experiment. The obtained upper limit of the branching ratio is Br(μ⁺ → e⁺γ) < 1.5 × 10 ^-11 at 90% confidence level (C.L.).