The CTA aims at the Inert Doublet Model

Abstract

We show that the Cherenkov Telescope Array (CTA) can realistically challenge the Inert Doublet Model, excluding its heavy regime up to dark matter masses of 800 GeV and probing a large fraction of the remaining viable parameter space at even higher masses. Two features of the Inert Doublet Model make it particularly suitable for CTA searches. First, the dark matter mass (in the heavy regime) must be larger than 500 GeV. Second, the dark matter annihilation cross section, $\sigma v$, is always larger than the thermal one, reaching values as high as $10^{-25} \mathrm{cm^3s^{-1}}$. This higher value of $\sigma v$ is the result of the unavoidable coannhilation effects that determine the relic density via thermal freeze-out in the early Universe. We find that with 100 hours of Galactic Center exposure, CTA's expected limit widely surpasses, even after the inclusion of systematic errors, current and projected bounds from Fermi-LAT and HESS on this model.