Flavor inspired model for dark matter

Abstract

The discrepancies between data on rare $b$-hadron decays, controlled by the underlying neutral-current transitions $b\ensuremath{\rightarrow}s{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}(\ensuremath{\ell}=e,\ensuremath{\mu})$, and the corresponding Standard Model predictions constitute one of the most intriguing hints for new physics. Leptoquarks are prime candidates to solve these anomalies and, in particular, the scalar leptoquark, ${S}_{3}$, triplet under $SU(2{)}_{L}$ with hypercharge $Y=\ensuremath{-}1/3$, provides a very good fit to data. Here, we entertain the possibility that the same scalar leptoquark ${S}_{3}$, responsible for the lepton flavor universality anomalies, is the portal to a fermionic dark sector consisting of two additional vectorlike fermions, one of which is a candidate for the cosmological dark matter. We study two scenarios, where the dark matter candidate belongs to an $SU(2{)}_{L}$ singlet and triplet respectively, and discuss the theory parameter space in the context of the dark matter candidate's relic density and prospects for direct and indirect dark matter searches. Direct detection rates are highly suppressed and generically below the neutrino floor. Current observations with, and future prospects for, high-energy gamma-ray telescopes such as HESS and the Cherenkov Telescope Array are much more promising, as they already provide powerful constraints on the models under consideration, and will potentially probe the full parameter space in the future.