Dark Matter Interactions with Sun-like Celestial Bodies An Exploration of How Sub-GeV Dark Matter Could Interact with Solar-like Media Through Linear Response Theory

Abstract

One interesting avenue in the search for dark matter is the possibility of dark mat ter interacting with celestial bodies, like our Sun, in such a way that the effects can be detected here on Earth. The purpose of this thesis is to investigate how sub-GeV Dirac-type dark matter particles could interact with the electrons in the Sun via a heavy dark photon. This study also aims to account for the surrounding medium and its effects on these scattering rates, Γ, through in-medium effects using the framework of linear response theory, specifically the density-density response function, χρρ. The impact of the medium will be demonstrated by comparing the scattering rates calculated through linear response theory to those calculated with out considering the medium. Using these calculated scattering rates, in both the heavy and light mediator limits, the resulting dark matter capture rates, C, inside the Sun, for various dark matter masses, mχ, and dark matter-electron reference cross sections, σ¯e, are calculated. Furthermore, the calculated scattering rates are applied to the phenomenon of solar dark matter reflection where in-medium effects are also demonstrated to be of some importance.