16–21 Oct 2022
PSI
Europe/Zurich timezone

Improved limits on lepton-flavor-violating decays of light pseudoscalars via spin-dependent μ→e conversion in nuclei

18 Oct 2022, 17:13
1m
WHGA / Foyer and Tent (PSI)

WHGA / Foyer and Tent

PSI

Speaker

Frederic Noël (ITP, AEC, Uni Bern)

Description

Lepton-flavor-violating decays of light pseudoscalars, $P=\pi^0,\eta,\eta'\to\mu e$, are stringently suppressed in the Standard Model up to tiny contributions from neutrino oscillations, so that their observation would be a clear indication for physics beyond the Standard Model. However, in effective field theory such decays proceed via axial-vector, pseudoscalar, or gluonic operators, which are, at the same time, probed in spin-dependent $\mu\to e$ conversion in nuclei. We derive master formulae that connect both processes in a model-independent way in terms of Wilson coefficients, and study the implications of current $\mu\to e$ limits in titanium for the $P\to\mu e$ decays. We find that these indirect limits surpass direct ones by many orders of magnitude.

based on: arXiv:2204.06005 [hep-ph]

Primary authors

Martin Hoferichter (University of Bern) Prof. Javier Menéndez (Department of Quantum Physics and Astrophysics and Institute of Cosmos Sciences, University of Barcelona) Frederic Noël (ITP, AEC, Uni Bern)

Presentation materials