Self-consistent bounds on Beyond the Standard Model bosons from spectroscopy of muonic atoms with magic nuclei

TL;DR

This paper develops a self-consistent method to analyze muonic atom spectroscopy data, simultaneously extracting nuclear and BSM physics parameters, leading to robust bounds on new physics and insights into nuclear parameter shifts.

Contribution

It introduces a combined analysis approach that self-consistently determines nuclear and BSM parameters from muonic atom data, improving the reliability of bounds on new physics.

Findings

Data are consistent with zero BSM coupling.

Robust exclusion bounds on BSM parameters are established.

Nuclear parameters are affected by BSM couplings in the fits.

Abstract

Spectroscopy of muonic atoms is, to date, the most accurate technique to extract parameters of the nuclear charge density. The same reasons for their heightened sensitivity to nuclear parameters, a large overlap of the muonic wavefunction with the nucleus, makes them attractive systems to test Beyond the Standard Model (BSM) Physics. This raises concerns of self-consistency as the same data are used to, first, extract nuclear parameters, and second, check the consistency with BSM models. We combine the two steps and self-consistently extract the nuclear and BSM parameters. We show that the data are consistent with vanishing BSM coupling and extract robust exclusion bounds. We further note that the nuclear parameters change under the influence of those BSM couplings on the parameter fits and compare with the fit solely based on quantum electrodynamics (QED).