A Search For Mu Yields E Gamma At The Level Of 10 Sup Minus 13 PDF Download

This report describes the status of the MEGA experiment, which is a search for the decay [mu] → e[gamma] with a branching ratio sensitivity of approximately 10−13. The observation of this decay would contradict the empirically established rule of lepton family number conservation and would indicate the existence of physics outside the standard model of electroweak interactions. The experimental design employs highly modular, fast detectors, state-of-the-art electronics, and a staged trigger with online filters. The detectors are contained in a 15 kG solenoidal field produced by a superconducting magnet. Positrons are confined to the central region and are measured by a set of thin MWPCs. Photons are measured by one of four layers of pair spectrometers in the outer region. Most aspects of the detector design have been validated in engineering runs; data taking will begin in 1990 with the electron arm and one pair spectrometer layer installed. 9 refs., 1 fig.