A handbook of vector-like quarks: mixing and single production

TL;DR

This paper reviews constraints on vector-like quarks, analyzes their effects on collider phenomenology, and explores their potential to explain anomalies and influence Higgs processes.

Contribution

It provides a comprehensive analysis of vector-like quark mixing constraints and their implications for LHC physics and electroweak anomalies.

Findings

Constraints from oblique corrections and Z decays limit vector-like quark mixing.

A hypercharge -5/6 doublet could explain the LEP forward-backward asymmetry.

Heavy quarks impact single Higgs production and decay at the LHC.

Abstract

We obtain constraints on the mixing of vector-like quarks coupling predominantly to the third generation. We consider all (seven) relevant types of vector-like quarks, individually. The constraints are derived from oblique corrections and Z -> b bbar measurements at LEP and SLC. We investigate the implications of these constraints on LHC phenomenology, concerning the decays of the heavy quarks and their single production. We also explore indirect effects of heavy quark mixing in top and bottom couplings. A remarkable effect is the possibility of explaining the anomalous forward-backward asymmetry in Z -> b bbar at LEP, with a hypercharge -5/6 doublet. We also study the impact of the new quarks on single Higgs production at the LHC and Higgs decay.