A novel experiment searching for the lepton flavour violating decay mu -> eee

Understand

Since the discovery of neutrino oscillations it is known that lepton flavour is not conserved.

• Lepton flavour violating processes in the charged lepton sector have so far however eluded detection; as they are heavily suppressed in the standard model of particle physics, an observation would be a clear signal for new physics and help to understand the source of neutrino masses and CP violation.
• We propose a novel experiment searching for the decay mu -> eee with the aim of ultimately reaching a sensitivity of 10^-16, an improvement by four orders of magnitude compared to previous experiments.
• The technologies enabling this step are thin high-voltage monolithic active pixel sensors for precise tracking at high rates with a minimum of material and scintillating fibres for high resolution time measurements.