Triplet-Quadruplet Dark Matter

TL;DR

This paper introduces a minimal electroweak dark matter model with fermionic triplet and quadruplets, analyzing its spectrum, relic abundance, and experimental constraints to identify viable parameter space for a 2.4 TeV dark matter candidate.

Contribution

It presents a novel UV-complete model of electroweak dark matter with specific fermionic multiplets and detailed analysis of its mass spectrum, relic density, and experimental constraints.

Findings

Dark matter candidate mass around 2.4 TeV can satisfy relic abundance.

One-loop corrections ensure the neutral fermion is the lightest.

Viable parameter space remains under current experimental constraints.

Abstract

We explore a dark matter model extending the standard model particle content by one fermionic $SU(2)_L$ triplet and two fermionic $SU(2)_L$ quadruplets, leading to a minimal realistic UV-complete model of electroweakly interacting dark matter which interacts with the Higgs doublet at tree level via two kinds of Yukawa couplings. After electroweak symmetry-breaking, the physical spectrum of the dark sector consists of three Majorana fermions, three singly charged fermions, and one doubly charged fermion, with the lightest neutral fermion $\chi_1^0$ serving as a dark matter candidate. A typical spectrum exhibits a large degree of degeneracy in mass between the neutral and charged fermions, and we examine the one-loop corrections to the mass differences to ensure that the lightest particle is neutral. We identify regions of parameter space for which the dark matter abundance is saturated for a standard cosmology, including coannihilation channels, and find that this is typically achieved for $m_{\chi_1^0}\sim 2.4~\mathrm{TeV}$. Constraints from precision electroweak measurements, searches for dark matter scattering with nuclei, and dark matter annihilation are important, but leave open a viable range for a thermal relic.