Status of MEG experiment at PSI

Abstract

The $\mu^+ \rightarrow e^+ \gamma$ decay is a key to understand physics beyond the standard model; if the decay is discovered, it is a clear evidence of new physics. If its branching ratio upper limit is improved by one order of magnitude, the result restricts the type of new physics in about twice larger energy scale. The MEG experiment, and its upgrade MEG II experiment, are experimental searches for the $\mu^+ \rightarrow e^+ \gamma$ decay by using intense DC muon beam provided at Paul Scherrer Institute in Switzerland. In this presentation we describe the result of MEG and report the preparation status of MEG II.