Title: A New Upper Limit on Charged Muon and Electron Number Violation from the MEG Experiment


The MEG experiment is designed to detect the decay u+→e+γ if the branching fraction is as big as 10-­‐13. Precise measurements of the photon and positron energies, the angle between them, and their relative time are used to reduce backgrounds. MEG uses a novel liquid xenon calorimeter for measuring the photon position, energy and time, and a drift chamber magnetic spectrometer and scintillation counters to measure the positron momentum and time. The collaboration recently completed analysis of large data sets collected in 2009 and 2010. I will briefly describe the motivation and history of this and related measurements and then describe the experimental technique used, report the recent results, and discuss prospects for improving the sensitivity in the next few years.