Searching for Lepton Flavour Violation with the Mu3e Experiment

TL;DR

The Mu3e experiment aims to detect lepton flavor violation in muon decays with unprecedented sensitivity, utilizing advanced silicon pixel sensors and timing detectors to suppress background and improve detection capabilities.

Contribution

This paper presents the design and expected sensitivity of the Mu3e experiment, which significantly advances the search for lepton flavor violation in muon decays.

Findings

Projected sensitivity of 2×10⁻¹⁵ for muon decay detection

Design of a high-precision tracking detector with silicon pixel sensors

Preparation status for construction and commissioning

Abstract

The upcoming Mu3e experiment searches for the lepton flavour violating decay $\mu^+\,\rightarrow\,e^+ e^- e^+$ with the aim of a final sensitivity of one signal decay in $10^{16}$ observed muon decays, an improvement over the preceding SINDRUM experiment by four orders of magnitude. In the first phase, the experiment will be operated at an existing intense muon beam line at the Paul Scherrer Institute. With muon stopping rates of about $10^{8}\text{s}^{-1}$, a single-event sensitivity of $2\cdot 10^{-15}$ can be achieved. For the ultimate sensitivity, a new high intensity muon beam line is required. In order to suppress background, the tracking detector is designed to measure low momentum electron and positron tracks with excellent precision by making use of very thin silicon pixel sensors. In addition, scintillating fibres and tiles provide precise timing information. Currently, the collaboration is finalizing the detector design and preparing for construction and commissioning.