Dark Matter in Inert Triplet Models

TL;DR

This paper investigates inert triplet scalar models as dark matter candidates, analyzing their viability against cosmological and experimental data, and identifying favored mass ranges for different hypercharge configurations.

Contribution

It provides a detailed analysis of inert triplet models with Y=0 and Y=2, highlighting their potential as dark matter candidates and constraints from observational data.

Findings

Y=0 triplet model favors ~5.5 TeV dark matter mass

Y=2 triplet model with ~2.8 TeV mass is excluded by direct detection

Y=2 model's spin-independent cross section is enhanced by Z exchange

Abstract

We study the inert triplet models, in which the standard model (SM) is extended to have a new SU(2)L triplet scalar (Y=0 or 2) with an Z2 symmetry. We show that the neutral component of the triplet can be a good dark matter candidate. In particular, for the hypercharge Y=0 triplet model, the WMAP data favors the region where the dark matter mass is around 5.5 TeV, which is also consistent with the direct detection experiments. In contrast, for the Y=2 model, although dark matter with its mass around 2.8 TeV is allowed by WMAP, it is excluded by the direct detection experiments because the spin-independent cross section is enhanced by the Z mediated tree-level scattering process.