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Searching for new physics at μ → e facilities with μ + and π + decays at rest

Hill, Richard J. (ORCID:000000031982589X)·Plestid, Ryan (ORCID:0000000307797289)·Zupan, Jure
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Abstract

We investigate the ability of μ → e facilities, Mu2e and COMET, to probe, or discover, new physics with their detector validation datasets. The validation of the detector response may be performed using a dedicated run with μ + , collecting data below the Michel edge, E e ≲ 52 MeV ; an alternative strategy using π + → e + ν e may also be considered. We focus primarily on a search for a monoenergetic e + produced via two-body decays μ + → e + X or π + → e + X , with X a light new physics particle. Mu2e can potentially explore new parameter space beyond present astrophysical and laboratory constraints for a set of well motivated models including axionlike particles with flavor violating couplings ( μ + → e + a ), massive Z ′ bosons ( μ + → Z ′ e + ), and heavy neutral leptons ( π + → e + N ). The projected sensitivities presented herein can be achieved in a matter of days. Published by the American Physical Society 2024

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Hill, Richard J. (ORCID:000000031982589X), Plestid, Ryan (ORCID:0000000307797289), Zupan, Jure. 2024-02-28. Searching for new physics at μ → e facilities with μ + and π + decays at rest. https://doi.org/10.1103/physrevd.109.035025

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