Probing the Inert Doublet Dark Matter Model with Cherenkov Telescopes

TL;DR

This paper investigates the potential of Cherenkov telescopes to detect gamma-ray signals from the inert doublet dark matter model, considering the Sommerfeld effect and spectral contributions, and compares indirect and direct detection prospects.

Contribution

It provides a detailed analysis of gamma-ray signals from the inert doublet dark matter model, including current constraints and future detection prospects with Cherenkov telescopes.

Findings

H.E.S.S. observations exclude some parameter space of the model.

For masses above 1 TeV, continuum photon constraints are stronger than spectral lines.

Cherenkov Telescope Array can probe significant parts of the high mass regime.

Abstract

We present a detailed study of the annihilation signals of the inert dark matter doublet model in its high mass regime. Concretely, we study the prospects to observe gamma-ray signals of the model in current and projected Cherenkov telescopes taking into account the Sommerfeld effect and including the contribution to the spectrum from gamma-ray lines as well as from internal bremsstrahlung. We show that present observations of the galactic center by the H.E.S.S. instrument are able to exclude regions of the parameter space that give the correct dark matter relic abundance. In particular, models with the charged and the neutral components of the inert doublet nearly degenerate in mass have strong gamma-ray signals. Furthermore, for dark matter particle masses above 1 TeV, we find that the non-observation of the continuum of photons generated by the hadronization of the annihilation products typically gives stronger constraints on the model parameters than the sharp spectral features associated to annihilation into monochromatic photons and the internal bremsstrahlung process. Lastly, we also analyze the interplay between indirect and direct detection searches for this model, concluding that the prospects for the former are more promising. In particular, we find that the upcoming Cherenkov Telescope Array will be able to probe a significant part of the high mass regime of the model.