Bayesian WIMP detection with the Cherenkov Telescope Array

TL;DR

This paper introduces a hierarchical Bayesian framework for detecting dark matter annihilation signals in Cherenkov Telescope Array data, allowing for flexible modeling of uncertainties and demonstrating comparable sensitivity to existing methods.

Contribution

It develops a novel hierarchical Bayesian inference approach for dark matter detection in CTA data, incorporating flexible priors and uncertainty modeling.

Findings

Sensitivity comparable to previous CTA estimates

Framework effectively incorporates theoretical uncertainties

Demonstrated with simulated scalar singlet dark matter data

Abstract

Over the past decades Bayesian methods have become increasingly popular in astronomy and physics as stochastic samplers have enabled efficient investigation of high-dimensional likelihood surfaces. In this work we develop a hierarchical Bayesian inference framework to detect the presence of dark matter annihilation events in data from the Cherenkov Telescope Array (CTA). Cosmic rays are weighted based on their measured sky position $\hat\Omega_m$ and energy $E_m$ in order to derive a posterior distribution for the dark matter's velocity averaged cross section $\langle\sigma v\rangle$. The dark matter signal model and the astrophysical background model are cast as prior distributions for $(\hat\Omega_m, E_m)$. The shape of these prior distributions can be fixed based on first-principle models; or one may adopt flexible priors to include theoretical uncertainty, for example, in the dark matter annihilation spectrum or the astrophysical distribution of sky location. We demonstrate the utility of this formalism using simulated data with a contribution from a scalar singlet dark-matter model. The sensitivity according to our method is comparable to previous estimates of the CTA sensitivity.