Gamma-rays from Heavy Minimal Dark Matter

TL;DR

This paper analyzes gamma-ray signals from minimal dark matter candidates, showing current H.E.S.S. data exclude certain mass ranges for fermionic 5-plet and scalar 7-plet models, with future telescopes promising deeper exploration.

Contribution

It provides the first detailed gamma-ray annihilation predictions for fermionic 5-plet and scalar 7-plet minimal dark matter models, including Sommerfeld and bremsstrahlung effects.

Findings

H.E.S.S. data exclude 1-20 TeV mass range for 5-plet and 7-plet dark matter

Current observations rule out these models as dominant dark matter forms

Cherenkov Telescope Array will probe higher mass ranges, including scalar 7-plet

Abstract

We consider the annihilation into gamma rays of Minimal Dark Matter candidates in the fermionic 5-plet and scalar 7-plet representations of $SU(2)_L$, taking into account both the Sommerfeld effect and the internal bremsstrahlung. Assuming the Einasto profile, we show that present measurements of the Galactic Center by the H.E.S.S. instrument exclude the 5-plet and 7-plet as the dominant form of dark matter for masses between 1 TeV and 20 TeV, in particular, the 5-plet mass leading to the observed dark matter density via thermal freeze-out. We also discuss prospects for the upcoming Cherenkov Telescope Array, which will be able to probe even heavier dark matter masses, including the scenario where the scalar 7-plet is thermally produced.