Probing the dark matter of a three-loop radiative neutrino mass generation model with the Cherenkov Telescope Array

We investigate the prospect of detecting the dark matter (DM) candidate in the three-loop radiative neutrino mass generation model extended with large electroweak multiplets of the Standard Model (SM) gauge group, at the future imaging atmospheric Cherenkov telescope known as the Cherenkov Telescope Array (CTA). We find that the addition of such large electroweak multiplets leads to a sizable Sommerfeld enhanced annihilation of the DM with an O(TeV) mass, into the SM gauge bosons, which results in continuum- and line-like spectra of very high-energy (VHE) gamma rays, and therefore becomes observable for the CTA. We determine the viable models by setting the upper limit on the SU(2)L isospin of the multiplets from the partial-wave unitarity constraints and the appearance of a low-scale Landau pole in the gauge coupling. Afterwards, by considering the continuum VHE gamma rays produced from the DM annihilation at the Galactic Center, we probe the parameter space of the model using the sensitivity reach of the CTA.