Flavor-changing signatures of spacetime-symmetry violations

Abstract

This proceedings contribution discusses Lorentz and CPT violation in the context of charged-lepton flavor-changing processes. Particular emphasis is placed on coherent muon-to-electron conversion in muonic atoms. Data collected by the SINDRUM~II experiment at the Paul Scherrer Institute is used to extract constraints on mass dimension $d=5$ electromagnetic and $d=6$ quark-lepton effects. The Mu2e experiment at Fermilab and COMET experiment at the Japan Proton Accelerator Complex are projected to improve constraints by up to two orders in magnitude.

Presented at the Tenth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, May 15-19, 2025