Phenomenology of Exotic Decays of Vector-Like Quark X5/3 into Doubly-Charged ScalarXinto Doubly-Charged Scalar

Sammanfattning: Searches for the Vector-Like Quarks usually look for their signatures assuming they decay purely into Standard Model particles. In this paper, we explore one possible exotic decay of the Vector-Like Quark with electric charge +5/3, X5/3. We adopt a simplified model which allows X5/3 to decay into a doubly-charged scalar S++ which further decays into a pair of same-sign leptons. We implement, validate and recast a recent CMS search for top quark partners with charge +5/3 in the same-sign dilepton final state. Our recast analysis provides a stringent bound of about 1.54 TeV on the mass of X5/3 for a wide range of masses of S++, independent of the chirality of the relevant couplings.