Single production of vector-like quarks with large width at the Large Hadron Collider

Vectorlike quarks (VLQs) are predicted by several theoretical scenarios of new physics and having colour quantum numbers they can copiously be produced at the Large Hadron Collider (LHC) so long that their mass is within the testable kinematic regime of this machine. While it would be convenient to assume that such objects are narrow and can be treated in the so-called narrow width approximation (NWA), this is not always possible: non-minimal new physics scenarios can predict VLQs with potentially large couplings and/or exotic decays, which can contribute to generate a large decay width for such extra quarks without being constrained by current bounds. In this analysis we consider single production of VLQs, which is rapidly becoming a channel of choice in experimental searches owing to the ever increasing limits on their mass, and we describe an approach to treat the large width regime which retains to a large extent a degree of model independence. We also consider the role of potentially sizable and model-dependent interference effects between different VLQ production and decay channels as well as between these and the corresponding irreducible background.