Gravitational Production of Hidden Photon Dark Matter in Light of the XENON1T Excess

TL;DR

This paper proposes a gravitational production mechanism for hidden photon dark matter that can explain the XENON1T excess, linking inflationary parameters to dark matter abundance and establishing bounds on the inflation scale and reheating temperature.

Contribution

It introduces a minimal gravitational production model for hidden photon dark matter and explores its parameter space in relation to inflationary and reheating scales.

Findings

Gravitational production can produce the correct relic abundance of hidden photon dark matter.

High-scale inflation with H_inf ≥ 7×10^11 GeV is compatible with 3 keV hidden photon dark matter.

Reheating temperature T_R ≥ 100 GeV is consistent with the model.

Abstract

Recently, the XENON1T experiment has reported an excess in the electronic recoil events. The excess is consistent with the interpretation of absorption of 3keV bosonic dark matter, for example, hidden photon dark matter with kinetic mixing of the order of $10^{-15}$. We point out that the minimally gravitational production provides a viable mechanism for obtaining a correct relic hidden photon abundance. We present parameter dependence of the hidden photon dark matter abundance on the inflationary scale $H_{\rm inf}$ and also the reheating temperature $T_{\rm R}$. We show that the inflationary Hubble scale and reheating temperature are both bounded from below, $H_{\rm inf}\gtrsim 7\times 10^{11}$GeV, $T_{\rm R}\gtrsim 10^2$GeV. In particular, the high-scale inflation is consistent with 3keV hidden photon dark matter.