KETTLE P. -R.

The MEG II experiment is designed to improve by an order of magnitude the sensitivity of 4.2×10−13 reached by MEG on the search for μ+→e+γ decay. A pixelated Timing Counter (pTC) has been developed to improve the time resolution by measuring the positron time information independently with several counters. We constructed and installed the pTC...

A positron timing counter (TC) with 30–40 ps time resolution for 50 MeV/c positrons required by the MEG II experiment has been developed. We employed a highly segmented design with 512 scintillator plates (120 × 40 × 5 mm3 and 120 × 50 × 5 mm3) read out by 6-SiPM-arrays at the both ends. Pile up is reduced by the segmented design and...

We present the first direct search for lepton flavour violating muon decay mediated by a new light particle X, μ+→e+X,X→γγ. This search uses a dataset resulting from 7.5 × 10 14 stopped muons collected by the MEG experiment at the Paul Scherrer Institut in the period 2009–2013. No significant excess is found in the mass region 20–45 MeV/c2 for...

The MEG experiment took data at the Paul Scherrer Institute in the years 2009–2013 to test the violation of the lepton flavor conservation law, which originates from an accidental symmetry that the Standard Model of elementary particle physics has, and published the most stringent limit on the charged lepton flavor violating decay µ+ → e+γ:...