Atomic Spectroscopy Probes of New Physics

TL;DR

Precision atomic spectroscopy is a powerful tool for probing potential new physics beyond the Standard Model by detecting tiny interactions through advanced experimental and theoretical methods.

Contribution

This review unifies theoretical frameworks, experimental strategies, and system sensitivities for spectroscopic searches of new light particles and interactions.

Findings

Updated spectroscopic constraints on benchmark models

Identification of atomic systems with highest sensitivity

Highlighting the complementary role of spectroscopy in new physics searches

Abstract

Precision spectroscopy has long played a central role in testing the foundations of physics, from the early insights that led to the development of quantum mechanics to the validation of quantum electrodynamics and the determination of fundamental constants. Today, advances in atomic and molecular spectroscopy enable sensitive searches for physics beyond the Standard Model. A broad class of well-motivated extensions predicts new light degrees of freedom with feeble couplings to electrons, muons, and nucleons, giving rise to tiny spin-independent interactions that can be probed at low energies. In this review, we present a unified overview of spectroscopic searches for such interactions. We discuss the effective theoretical framework connecting fundamental interactions to atomic and nuclear observables, survey the key experimental and theoretical strategies, and review the atomic and molecular systems providing the strongest sensitivity. We conclude with updated spectroscopic constraints on representative benchmark models, highlighting the unique and complementary role of precision spectroscopy in exploring new fundamental interactions.