NAKAO , M.

The MEG II experiment (Baldini et al., 2018) [1] is designed to improve the sensitivity to the μ +→e + γ decay. A crucial component is the Pixelated Timing Counter (pTC), dedicated to the measurement of the positron time to reduce the combinatorial background (Cattaneo et al., 2014; Nishimura et al., 2016) [3,4]. The detector consists of 512...

We studied the impact of radiation damage on scintillation counters read out by six SiPMs connected in series focusing on their time resolution. Six SiPMs from AdvanSiD were irradiated step by step with a 37 MBq 90Sr source. At the integrated dose expected at the end of the MEG II experiment, the time resolution at 30 °C was measured to be...

A new timing detector has been developed to measure ∼50 MeV/c positrons with a time resolution of σt≃30ps in the MEG II experiment. The detector are segmented into 512 scintillation counters, each of which consists of 120×(40or50)×5mm3 size BC-422 and two arrays of six AdvanSiD silicon photomultipliers. The single-counter resolutions are...

The development of a Timing Counter detector with a resolution in the range of ≈ 30 ps will be presented. The detector was designed for the upgrade of the MEG II experiment looking for the μ+→ e+γ decay with an improved sensitivity of one order of magnitude with respect to the previous MEG setup. In this paper the design of the TC single pixel...

The MEG II experiment at Paul Scherrer Institut in Switzerland will search for the lepton flavour violating muon decay, μ+→ e+\gamma, with a sensitivity of 4× 10-14improving the existing limit of an order of magnitude. In 2016, we finished the construction of the MEG II Timing Counter, the subdetector dedicated to the measurement of the...

The MEG experiment, designed to search for the μ+→ e+γ decay, completed data-taking in 2013 reaching a sensitivity level of 5.3 × 10- 13for the branching ratio. In order to increase the sensitivity reach of the experiment by an order of magnitude to the level of 6 × 10- 14, a total upgrade, involving substantial changes to the experiment, has...

The MEG II experiment, located at the Paul Scherrer Institut (PSI) in Switzerland, is the successor to the MEG experiment, which completed data taking in 2013. MEG II started fully operational data taking in 2021, with the goal of improving the sensitivity of the mu+-> e+gamma\documentclass[12pt]{minimal} \usepackage{amsmath}...

The MEG II experiment, located at the Paul Scherrer Institut (PSI) in Switzerland, is the successor to the MEG experiment, which completed data taking in 2013. MEG II started fully operational data taking in 2021, with the goal of improving the sensitivity of the mu+-> e+gamma\documentclass[12pt]{minimal} \usepackage{amsmath}...

The MEG II experiment, based at the Paul Scherrer Institut in Switzerland, reports the result of a search for the decay mu(+)-> e(+)gamma from data taken in the first physics run in 2021. No excess of events over the expected background is observed, yielding an upper limit on the branching ratio of B (mu(+)-> e(+)gamma) <7.5x10(-13) (90% CL)....