# Muon-to-Electron Conversion in Mirror Fermion Model with Electroweak Scale Non-Sterile Right-handed Neutrinos

## TL;DR

This paper investigates muon-to-electron conversion in nuclei within a mirror fermion model featuring electroweak-scale non-sterile right-handed neutrinos, deriving relations to muon decay rates and constraining model parameters with current and future experimental data.

## Contribution

It provides a simple formula linking muon-to-electron conversion rates with muon decay, and constrains model parameters using experimental limits, exploring sensitivities for mirror lepton masses 100-800 GeV.

## Key findings

- Conversion rates relate to muon decay rates at zero momentum transfer.
- Current experiments constrain Yukawa couplings for mirror leptons 100-800 GeV.
- Future experiments can probe very small Yukawa couplings depending on the scenario.

## Abstract

The muon-to-electron conversion in nuclei like aluminum, titanium and gold is studied in the context of a class of mirror fermion model with non-sterile right-handed neutrinos having mass at the electroweak scale. At the limit of zero momentum transfer and large mirror lepton masses, we derive a simple formula to relate the conversion rate with the on-shell radiative decay rate of muon into electron. Current experimental limits (SINDRUM II) and projected sensitivities (Mu2e, COMET and PRISM) for the muon-to-electron conversion rates in various nuclei and latest limit from MEG for the radiative decay rate of muon into electron are used to put constraints on the parameter space of the model. Depending on the nuclei targets used in different experiments, for the mirror lepton mass in the range of 100 to 800 GeV, the sensitivities of the new Yukawa couplings one can probe in the near future are in the range of one tenth to one hundred-thousandth, depending on the mixing scenarios in the model.