Global study of effective Higgs portal dark matter models using GAMBIT

TL;DR

This study uses GAMBIT to perform a comprehensive global fit of Higgs portal dark matter models, analyzing parameter spaces under various experimental constraints with advanced statistical techniques.

Contribution

It provides the first combined frequentist and Bayesian analysis of vector and Majorana fermion Higgs portal DM models using GAMBIT, including detailed parameter space exploration and public data release.

Findings

Viable solutions at low and high vector masses.

Majorana model favors CP-odd, parity-violating couplings.

Momentum-suppressed DM-nucleon cross-section in Majorana model.

Abstract

In this proceeding, we present frequentist and Bayesian results from a global fit of effective vector and Majorana fermion Higgs portal dark matter (DM) models using the $\mathsf{GAMBIT}$ software. We systematically explore the parameter space of these models using advanced sampling techniques to simultaneously satisfy the observed DM abundance, Higgs invisible decay, and indirect and direct detection limits. In addition, we take account of a set of nuisance parameters arising from Standard Model, nuclear physics, DM halo and velocity distribution. For the vector DM model viable solutions are found at low and high vector masses. The Majorana fermion model requires a strong preference for a CP-odd, parity-violating coupling which leads to a momentum-suppression of the DM-nucleon cross-section. All of our results, samples and input files are publicly available via $\href{https://www.zenodo.org/communities/gambit-official/}{\textsf{Zenodo}}$.