Secluded Dark Matter in light of the Cherenkov Telescope Array (CTA)

Abstract: Secluded dark matter is one of the most popular dark matter models, where dark matter annihilations go into particles that belong to a dark sector. An interesting way to probe such models is via indirect detection. In particular, gamma-ray observations are rather promising. Taking into account $1\%$ level of systematics, in this work we show that the Cherenkov Telescope Array (CTA) will place the most stringent bounds on the dark matter annihilation cross section, surpassing existing probes based on H.E.S.S., Fermi-LAT, and Planck data, for dark matter masses above $400$ GeV, independently of the channel and choosing the Einasto profile. We consider scenarios of secluded annihilations into leptophilic, leptophobic scalars and Higgs-like particles being able to exclude an annihilation cross section of $1.7 \times 10^{-25}$ cm$^3 \,$s$^{-1}$ for $m_{DM}=5000$ GeV, for $\phi \to e^+e^-$ channel, for example, exceeding the current limits by one order of magnitude.