Production of extra quarks at the Large Hadron Collider beyond the Narrow Width Approximation

TL;DR

This paper investigates the impact of finite width and interference effects on the production and decay of heavy vector-like quarks at the LHC, challenging standard assumptions and evaluating current experimental analysis performance.

Contribution

It assesses the validity of current experimental approaches by including finite width and interference effects in heavy quark production models at the LHC.

Findings

Finite width and interference effects significantly affect exclusion limits.

Current analyses are valid only within certain mass and width regimes.

Breakdowns occur for specific mass, width, and coupling configurations.

Abstract

This paper explores the effects of both finite width and interference (with background) in the pair production and decay of extra heavy quarks with charge 2/3 at the Large Hadron Collider (LHC). This dynamics is normally ignored in standard experimental searches and we assess herein the regions of validity of current approaches, also evaluating the performances of a set of current experimental analyses at 8 and 13 TeV for the deterimination of the excluded regions in the $(M_{\rm VLQ},\Gamma_{\rm VLQ})$ plane, $M_{\rm VLQ}$ being the mass of the VLQ and $\Gamma_{\rm VLQ}$ its width. Further, we discuss the configurations of masses, widths and couplings where the latter breaks down.