# Pseudo-Nambu-Goldstone dark matter and two-Higgs-doublet models

## TL;DR

This paper proposes a dark matter model where a pseudo-Nambu-Goldstone boson, arising from a complex scalar singlet, interacts weakly with nucleons, making it difficult to detect directly but consistent with relic abundance and Higgs data.

## Contribution

It introduces a novel dark matter candidate based on a pseudo-Nambu-Goldstone boson within a two-Higgs-doublet framework, highlighting its suppressed direct detection signals.

## Key findings

- The dark matter candidate evades direct detection due to vanishing scattering amplitude.
- The model remains consistent with relic abundance and Higgs measurement constraints.
- Indirect detection constraints are also considered in the analysis.

## Abstract

We study a dark matter model with one singlet complex scalar and two Higgs doublets. The scalar potential respects a softly broken global symmetry, which makes the imaginary part of the singlet become a pseudo-Nambu-Goldstone boson acting as a dark matter candidate. The pseudo-Nambu-Goldstone nature of the boson leads to the vanishing of its tree-level scattering amplitude off nucleons at zero momentum transfer. Therefore, although the interaction strength could be sufficiently large to yield a viable relic abundance via thermal mechanism, direct detection is incapable of probing this candidate. We further investigate the constraints from Higgs measurements, relic abundance observation, and indirect detection.