Heavy vector-like quark with charge 5/3 at the LHC

A bstract We study the phenomenology at the Large Hadron Collider of an exotic vector-like quark with charge +5/3. We relax the assumption of a 100% branching into Wt and allow for an arbitrary rate into W plus light quarks, thus covering all possible scenarios. Sizeable decays into light quarks can be achieved, for instance, in a model where the X 5/3 quark is embedded in a doublet with hypercharge 7/6, which also contains a t ′ quark. We study the bounds on the parameter space of this model, and perform a detailed simulation of the X 5/3 pair production and decays. We show that the final state with WtWq , where q = u or c , contributes to the same sign dilepton searches, and that the reach can be improved with alternative cuts optimised on such final state.