Probing dark matter in 2HDM+S with MeerKAT Galaxy Cluster legacy survey

Abstract

The unknown nature of dark matter remains an eyesore on our cosmological paradigm. As it is believed to constitute the majority of the matter content of the Universe, determining its properties is imperative to our understanding of the formation and evolution of the Universe. Weakly Interacting Massive Particles (WIMPs) are predicted to produce diffuse synchrotron emission as an indirect consequence of their annihilation. Radio frequency dark matter searches are gaining in prevalence due to the high sensitivity and resolution capabilities of the new generation of radio interferometers. MeerKAT is currently the best instrument of its kind in the southern hemisphere, making it a prime instrument for indirect dark matter searches. By making use of publicly available galaxy cluster data from the MeerKAT Galaxy Cluster Legacy Survey we are able to use the diffuse emission observed in clusters to constrain the dark matter parameter space. In this work we consider three generic WIMP annihilation channels (bb, μ+μ−, τ +τ −) as a representation of the larger total set of possible channels. Additionally, we probe the properties of the dark matter candidate within the 2HDM+S particle physics model, which was developed as an explanation to various anomalies observed in the Large Hadron Collider data from runs 1 and 2. This model has been considered as a potential explanation to various astrophysical anomalies due to the overlapping predicted mass ranges. We undertake a statistical analysis of the radio flux densities within galaxy clusters, considering radio halos, mini halos and a non-detection of diffuse emission, to produce upper limits on the dark matter annihilation cross section. We are able to exclude the thermal relic value for WIMP masses < 200 GeV. We show that within the uncertainty band of the dark matter density profile, 2HDM+S remains a viable explanation for the various astrophysical excesses. We produce some of the first WIMP dark matter constraints produced with MeerKAT, which are comparable to some of the most stringent limits to date.