Dark photon dark matter and fast radio bursts

TL;DR

This paper explores how dark photon dark matter could influence the observed time delays in fast radio bursts, finding that its effects are minimal and do not challenge existing constraints.

Contribution

It introduces a novel method to constrain dark photon dark matter using FRB time delays, accounting for mixing effects and intergalactic medium interactions.

Findings

Dark photon DM causes negligible variation in FRB time delays.

Current bounds on photon mass and equivalence principle remain valid.

The impact of DP DM on FRB delays is consistent across multiple observed events.

Abstract

The nature of dark matter (DM) is still a mystery that may indicate the necessity for extensions of the Standard Model (SM). Light dark photons (DP) may comprise partially or entirely the observed DM density and existing limits on the DP DM parameter space arise from several cosmological and astrophysical sources. In the present work we investigate DP DM using cosmic transients, specifically fast radio bursts (FRBs). The observed time delay of radio photons with different energies have been used to constrain the photon mass or the Weak Equivalence Principle, for example. Due to the mixing between the visible and the DP, the time delay of photons from these cosmic transients, caused by free electrons in the intergalactic medium, can change and impact those constraints from FRBs. We use five detected FRBs and two associations of FRBs with gamma-ray bursts to investigate the correspondent variation on the time delay caused by the presence of DP DM. The result is virtually independent of the FRB used and this variation is very small, considering the still allowed DP DM parameter space, not jeopardizing current bounds on other contributions of the observed time delay.