PreprintCC BY 4.0arXiv
An Operator Analysis of Radiative Muon Decay
Abstract
New physics beyond the Standard Model (SM) may induce new four-fermion interactions. We investigate the sensitivity of radiative muon decay, μ-→ e-ν̅eνμγ, to such four-fermion interactions of mass dimension seven and eight. For each operator, we calculate its interference with the SM amplitude and obtain an analytic expression for the decay rate. We apply these to a log-likelihood comparison for a benchmark sample of 105 events, and find that these operator contributions can be distinguished from the SM prediction at characteristic coefficient magnitudes between 10−9 and 10−8.
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BibTeX
@misc{rajaraman2026operator,
title = {{An Operator Analysis of Radiative Muon Decay}},
author = {Arvind Rajaraman and Chao-Hsiang Sheu},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.36841},
eprint = {2609.36841},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.36841},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - An Operator Analysis of Radiative Muon Decay
AU - Arvind Rajaraman
AU - Chao-Hsiang Sheu
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2609.36841
UR - https://arxiv.org/abs/2609.36841
AB - New physics beyond the Standard Model (SM) may induce new four-fermion interactions. We investigate the sensitivity of radiative muon decay, μ^-→ e^-ν̅_eν_μγ, to such four-fermion interactions of mass dimension seven and eight. For each operator, we calculate its interference with the SM amplitude and obtain an analytic expression for the decay rate. We apply these to a log-likelihood comparison for a benchmark sample of 10^5 events, and find that these operator contributions can be distinguished from the SM prediction at characteristic coefficient magnitudes between 10^−9 and 10^−8.
ER -