# Dark photon searches with atomic transitions

## TL;DR

This paper proposes a novel atomic transition-based experiment to detect dark photons, significantly improving constraints on their properties in the meV mass range compared to previous methods.

## Contribution

It introduces a new experimental approach using atomic transitions for dark photon detection, extending sensitivity in the meV mass range by up to eight orders of magnitude.

## Key findings

- Extended constraints on dark photon mixing parameters in the meV mass range.
- Proposed experimental method enhances detection sensitivity for low-mass dark photons.
- Demonstrated potential to improve existing bounds by several orders of magnitude.

## Abstract

Dark matter could be made up of dark photons, massive but very light particles whose interactions with matter resemble those of usual photons but suppressed by a small mixing parameter. We analyze the main approaches to dark photon interactions and how they can be applied to direct detection experiments which test different ranges of masses and mixings. A new experiment based on counting dark photons from induced atomic transitions in a target material is proposed. This approach appears to be particularly appropriate for dark photon detection in the meV mass range, extending the constraints in the mixing parameter by up to eight orders of magnitude with respect to previous experiments.