Global fit of pseudo-Nambu-Goldstone Dark Matter

TL;DR

This paper conducts a comprehensive global analysis of the pseudo-Nambu-Goldstone dark matter model, integrating multiple experimental constraints and identifying key parameter regions compatible with current observations and potential signals.

Contribution

It provides the first combined frequentist and Bayesian global fit of this DM model, including gamma-ray likelihoods and one-loop cross section calculations.

Findings

Identifies two favored annihilation channels: Higgs funnel and Higgs pair production.

Both regions are compatible with Fermi-LAT dwarf galaxy observations.

The Higgs funnel is difficult to probe, while Higgs pair annihilation can be tested with current and future experiments.

Abstract

We perform a global fit within the pseudo-Nambu-Goldstone dark matter (DM) model emerging from an additional complex scalar singlet with a softly broken global U(1) symmetry. Leading to a momentum-suppressed DM-nucleon cross section at tree level, the model provides a natural explanation for the null results from direct detection experiments. Our global fit combines constraints from perturbative unitarity, DM relic abundance, Higgs invisible decay, electroweak precision observables and latest Higgs searches at colliders. The results are presented in both frequentist and Bayesian statistical frameworks. Furthermore, post-processing our samples, we include the likelihood from gamma-ray observations of $\mathit{Fermi}$-LAT dwarf spheroidal galaxies and compute the one-loop DM-nucleon cross section. We find two favoured regions characterised by their dominant annihilation channel: the Higgs funnel and annihilation into Higgs pairs. Both are compatible with current $\mathit{Fermi}$-LAT observations, and furthermore, can fit the slight excess observed in four dwarfs in a mass range between about 30-300 GeV. While the former region is hard to probe experimentally, the latter can partly be tested by current observations of cosmic-ray antiprotons as well as future gamma-ray observations.