Improved limits on interactions of low-mass spin-0 dark matter from atomic clock spectroscopy

TL;DR

This paper uses atomic clock spectroscopy to set new, significantly improved limits on the interactions of low-mass spin-0 dark matter particles with Standard Model particles, constraining their coupling strengths.

Contribution

It provides the first comprehensive analysis of atomic clock data to constrain both linear and quadratic interactions of low-mass scalar dark matter with fundamental constants.

Findings

New limits on linear Higgs coupling improved by 2-3 orders of magnitude.

Constraints on quadratic photon and quark interactions established.

Demonstrates atomic clocks' sensitivity to low-mass dark matter interactions.

Abstract

Low-mass (sub-eV) spin-0 dark matter particles, which form a coherently oscillating classical field $\phi = \phi_0 \cos(m_\phi t)$, can induce oscillating variations in the fundamental constants through their interactions with the Standard Model sector. We calculate the effects of such possible interactions, which may include the linear interaction of $\phi$ with the Higgs boson, on atomic and molecular transitions. Using recent atomic clock spectroscopy measurements, we derive new limits on the linear interaction of $\phi$ with the Higgs boson, as well as its quadratic interactions with the photon and light quarks. For the linear interaction of $\phi$ with the Higgs boson, our derived limits improve on existing constraints by up to $2-3$ orders of magnitude.