Probing photophobic axion and relaxion dark matter

Nayara Fonseca,Enrico Morgante

doi:10.1103/physrevd.103.015011

Abstract

We investigate the interplay between early universe cosmology and dark matter direct detection, considering axion models with naturally suppressed couplings to photons. In the context of the cosmological relaxation of the electroweak scale, we focus on a scenario of \emph{Relaxion Dark Matter}, in which the relaxion field constitutes all the observed dark matter relic density and its allowed mass range is fixed to a few $\mathrm{keV}$ by construction. In particular, we show that a relaxion particle with mass $m_\phi= 3.0 \,\mathrm{keV}$ which couples to electrons with $g_{\phi, e}= 6.8 \times 10^{-14}$ is consistent with the XENON1T excess, while accounting for the observed dark matter and satisfying astro/cosmo probes. This scenario uses the electroweak scale as the link connecting the relaxion production at early times with the dark matter absorption rate in direct detection.

Highlights

In the last decades there has been a huge effort to understand the nature of dark matter (DM)
In the context of the cosmological relaxation of the electroweak scale, we focus on a scenario of relaxion dark matter, in which the relaxion field constitutes all the observed dark matter relic density and its allowed mass range is fixed to a few keV by construction
We show that a relaxion particle with mass mφ 1⁄4 3.0 keV which couples to electrons with gφ;e 1⁄4 6.8 × 10−14 is consistent with the XENON1T excess, while accounting for the observed dark matter and satisfying astro/cosmo probes

Summary

Probing photophobic axion and relaxion dark matter

We investigate the interplay between early universe cosmology and dark matter direct detection, considering axion models with naturally suppressed couplings to photons. In the context of the cosmological relaxation of the electroweak scale, we focus on a scenario of relaxion dark matter, in which the relaxion field constitutes all the observed dark matter relic density and its allowed mass range is fixed to a few keV by construction. We show that a relaxion particle with mass mφ 1⁄4 3.0 keV which couples to electrons with gφ;e 1⁄4 6.8 × 10−14 is consistent with the XENON1T excess, while accounting for the observed dark matter and satisfying astro/cosmo probes. This scenario uses the electroweak scale as the link connecting the relaxion production at early times with the dark matter absorption rate in direct detection

INTRODUCTION

NAYARA FONSECA and ENRICO MORGANTE

Relaxion DM

CONCLUSIONS