Status of charged lepton flavour violation search with MEG II experiment

TL;DR

The MEG II experiment aims to detect charged lepton flavor violation through the $\,\mu\rightarrow e\gamma$ decay, with upgraded detectors to improve sensitivity and explore physics beyond the Standard Model.

Contribution

This paper details the design, performance, and initial results of the upgraded MEG II detectors, advancing the search for charged lepton flavor violation.

Findings

Successful detector upgrade completed

Pre-engineering run results demonstrate detector performance

Current status shows promising sensitivity improvements

Abstract

The MEG II experiment searches for the Charged Lepton Flavour Violating (CLFV) decay $\mu\rightarrow e \gamma$. This decay is foreseen by the Standard Model (SM) of Particle Physics at non observable rates through neutrino oscillation. Observing it would be a clear signal of new physics (e.g. SUSY-GUT). After publishing the current upper limit to the Branching Ratio (BR) of this decay in 2016, BR($\mu^+\rightarrow e^+ \gamma)<4.2\times10^{-13}$, the MEG experiment started the upgrade of its detector in order to increase the sensitivity by a factor 10, starting the MEG II phase. The aim of this work is to report a description of the new detectors design and performances, to present the results obtained in the 2018 pre-engineering run with all the new MEG II detectors installed, and to report on the current status of the experiment and its future prospects.