# Muon-electron lepton-flavor violating transitions: shell-model calculations of transitions in 27Al

## TL;DR

This paper presents advanced shell-model calculations for muon-to-electron lepton-flavor violating transitions in 27Al, highlighting the dominance of coherent ground-state transitions and minimal impact of excited states.

## Contribution

It extends previous shell-model studies by including p orbitals to assess the influence of negative-parity states on conversion rates.

## Key findings

- Coherent ground-state transitions dominate the process.
- Excited positive- or negative-parity states have negligible effects.
- Including p orbitals confirms the minimal impact of negative-parity states.

## Abstract

In this paper we present the results of large-scale shell-model calculations of muon-to-electron lepton-flavor violating transitions for the case of the target nucleus 27Al. We extend the previous shell-model calculations, done in the sd model space, by including also the p orbitals in order to see whether the negative-parity states produce any significant effect in the conversion rate. The analysis of the results shows the dominance of coherent transitions mediated by isovector operators and going by the ground state of the target, with practically null influence of excited positive- or negative-parity states.