Michel decay spectrum for a muon bound to a nucleus

TL;DR

This paper refines the theoretical understanding of the electron spectrum from muons bound to nuclei, resolving previous discrepancies and aiding future searches for new physics with high-precision muon experiments.

Contribution

It demonstrates that radiative corrections reconcile theory with experimental data and provides more accurate predictions for muon decay spectra in atomic bound states.

Findings

Radiative corrections eliminate previous spectrum discrepancies.

Enhanced theoretical predictions support future high-precision muon experiments.

The work bridges atomic, nuclear, and high-energy physics techniques.

Abstract

The spectrum of electrons from muons decaying in an atomic bound state is significantly modified by their interaction with the nucleus. Somewhat unexpectedly, its first measurement, at the Canadian laboratory TRIUMF, differed from basic theory. We show, using a combination of techniques developed in atomic, nuclear, and high-energy physics, that radiative corrections eliminate the discrepancy. In addition to solving that outstanding problem, our more precise predictions are potentially useful for interpreting future high-statistics muon experiments that aim to search for exotic interactions at $10^{-16}$ sensitivity.