Scalar Multiplet Dark Matter

TL;DR

This paper systematically studies scalar multiplet dark matter models up to n=7, analyzing how scalar couplings affect relic abundance and detection signatures, and explores their connection to neutrino masses and leptogenesis.

Contribution

It provides a comprehensive analysis of scalar multiplet dark matter phenomenology, including the effects of scalar couplings on relic abundance and detection, and links to neutrino mass generation and leptogenesis.

Findings

Relic abundance ranges depend on scalar couplings.

Detection signatures can be significantly enhanced by quartic couplings.

Adding right-handed neutrinos enables a minimal, TeV-scale model for dark matter, neutrino masses, and leptogenesis.

Abstract

We perform a systematic study of the phenomenology associated to models where the dark matter consists in the neutral component of a scalar SU(2)_L n-uplet, up to n=7. If one includes only the pure gauge induced annihilation cross-sections it is known that such particles provide good dark matter candidates, leading to the observed dark matter relic abundance for a particular value of their mass around the TeV scale. We show that these values actually become ranges of values -which we determine- if one takes into account the annihilations induced by the various scalar couplings appearing in these models. This leads to predictions for both direct and indirect detection signatures as a function of the dark matter mass within these ranges. Both can be largely enhanced by the quartic coupling contributions. We also explain how, if one adds right-handed neutrinos to the scalar doublet case, the results of this analysis allow to have altogether a viable dark matter candidate, successful generation of neutrino masses, and leptogenesis in a particularly minimal way with all new physics at the TeV scale.