Direct detection of pseudo-Nambu-Goldstone dark matter in a two Higgs doublet plus singlet extension of the SM

TL;DR

This paper calculates loop-level dark-matter-nucleon scattering cross sections in a two Higgs doublet plus singlet extension of the Standard Model, showing that future experiments could detect such interactions despite current constraints.

Contribution

It provides the first detailed calculation of loop-induced scattering cross sections in the pseudo-Nambu-Goldstone dark matter model with a second Higgs doublet, highlighting their potential detectability.

Findings

Loop corrections enable non-zero scattering cross sections.

Current experiments barely constrain the model.

Future experiments could detect the predicted signals.

Abstract

We calculate the leading radiative corrections to the dark-matter-nucleon scattering in the pseudo-Nambu-Goldstone dark matter model augmented with a second Higgs doublet (S2HDM). In this model, the cross sections for the scattering of the dark-matter on nuclei vanishes at tree-level in the limit of zero momentum-transfer due to a U(1) symmetry. However, this symmetry is softly broken in order to give a mass to the dark-matter particle. As a consequence, non-vanishing scattering cross sections arise at the loop level. We find that the current cross-section limits from dark-matter direct-detection experiments can hardly constrain the parameter space of the S2HDM. However, the loop-corrected predictions for the scattering cross sections can be well within the reach of future direct-detection experiments. As a consequence, future phenomenological analyses of the S2HDM should take into account cross-section predictions beyond tree-level and the experimental constraints from dark-matter direct-detection experiments.