Probing fast oscillating scalar dark matter with atoms and molecules

TL;DR

This paper discusses the WReSL experiment's efforts to detect rapid oscillations in fundamental constants caused by scalar dark matter, extending previous slow variation searches to include molecules for enhanced sensitivity.

Contribution

It introduces a novel experimental approach to search for fast oscillating scalar dark matter effects on fundamental constants using atomic and molecular spectroscopy.

Findings

Progress in measuring rapid fundamental constant variations

Extension of the search to molecular systems

Potential sensitivity to relaxion dark matter models

Abstract

Light scalar Dark Matter with scalar couplings to matter is expected within several scenarios to induce variations in the fundamental constants of nature. Such variations can be searched for, among other ways, via atomic spectroscopy. Sensitive atomic observables arise primarily due to possible changes in the fine-structure constant or the electron mass. Most of the searches to date have focused on slow variations of the constants (i.e. modulation frequencies $<$ 1 Hz). In a recent experiment \mbox{[Phys. Rev. Lett. 123, 141102 (2019)]} called WReSL (Weekend Relaxion-Search Laboratory), we reported on a direct search for rapid variations in the radio-frequency band. Such a search is particularly motivated within a class of relaxion Dark Matter models. We discuss the WReSL experiment, report on progress towards improved measurements of rapid fundamental constant variations, and discuss the planned extension of the work to molecules, in which rapid variations of the nuclear mass can be sensitively searched for.