Dark Matter From Weak Polyplets

TL;DR

This paper explores new fermion multiplets called polyplets as potential dark matter candidates, analyzing their stability, interactions, and experimental constraints within an extended Standard Model framework.

Contribution

It introduces a simple polyplet model with a discrete symmetry to stabilize dark matter and examines its viability considering collider, precision, and relic density constraints.

Findings

Viable dark matter candidate for large Higgs masses

Model can produce subdominant relic density at 125 GeV Higgs

Constraints from collider and direct detection experiments considered

Abstract

The addition of new multiplets of fermions charged under the Standard Model gauge group is investigated, with the aim of identifying a possible dark matter candidate. These fermions are charged under $SU(2)\times U(1)$, and their quantum numbers are determined by requiring all new particles to obtain masses via Yukawa couplings and all triangle anomalies to cancel as in the Standard Model; more than one multiplet is required and we refer to such a set of these multiplets as a polyplet. For sufficiently large multiplets, the stability of the dark matter candidate is ensured by an accidental symmetry; for clarity, however, we introduce a model with a particularly simple polyplet structure and stabilize the dark matter by imposing a new discrete symmetry. We then explore the features of this model; constraints from colliders, electroweak precision measurements, the dark matter relic density, and direct detection experiments are considered. We find that the model can accommodate a viable dark matter candidate for large Higgs boson masses; for $m_H\sim 125$ GeV, a subdominant contribution to the dark matter relic density can be achieved.