Results from Pilot Run for MEG II Positron Timing Counter

TL;DR

The paper reports on the initial results of a pilot run for the MEG II experiment's Timing Counter, demonstrating improved timing resolution crucial for detecting rare muon decays.

Contribution

It presents the successful construction and initial testing of the MEG II Timing Counter with a pilot run showing resolution improvements over previous setups.

Findings

Timing resolution improved by a factor of two

Successful operation of the pilot run

Validation of detector performance

Abstract

The MEG II experiment at Paul Scherrer Institut in Switzerland will search for the lepton flavour violating muon decay, $\mu^+\to e^+\gamma$, with a sensitivity of $4\times10^{-14}$ improving 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 positron emission time. The first one-fourth of it was installed in the experimental area and we performed a pilot run with the MEG~II beam of $7\times10^{7}\mu^+/$s. The timing resolution reached the design value improving by a factor of two compared to MEG.