On the direct detection of multi-component dark matter: sensitivity studies and parameter estimation

TL;DR

This paper investigates how future direct detection experiments can identify and distinguish multi-component dark matter signals, analyzing parameter estimation and the impact of various physical factors on detection sensitivity.

Contribution

It provides a comprehensive analysis of the conditions under which multi-component dark matter can be detected and distinguished, including parameter estimation and degeneracy resolution.

Findings

Two-component dark matter hypotheses can be discriminated based on mass splitting.

Including interaction strength and local density variations affects detection sensitivity.

Parameter estimation accuracy depends on experimental configurations and signal degeneracies.

Abstract

We study the case of multi-component dark matter, in particular how direct detection signals are modified in the presence of several stable weakly-interacting-massive particles. Assuming a positive signal in a future direct detection experiment, stemming from two dark matter components, we study the region in parameter space where it is possible to distinguish a one from a two-component dark matter spectrum. First, we leave as free parameters the two dark matter masses and show that the two hypotheses can be significantly discriminated for a range of dark matter masses with their splitting being the critical factor. We then investigate how including the effects of different interaction strengths, local densities or velocity dispersions for the two components modifies these conclusions. We also consider the case of isospin-violating couplings. In all scenarios, we show results for various types of nuclei both for elastic spin-independent and spin-dependent interactions. Finally, assuming that the two-component hypothesis is confirmed, we quantify the accuracy with which the parameters can be extracted and discuss the different degeneracies that occur. This includes studying the case in which only a single experiment observes a signal, and also the scenario of having two signals from two different experiments, in which case the ratios of the couplings to neutrons and protons may also be extracted.