Generalization of exotic quark searches

TL;DR

This paper sets new limits on the masses of exotic heavy quarks T, B, and X using CMS data, excluding certain mass ranges at 95% confidence level across various models and branching fractions.

Contribution

It provides the first comprehensive mass limits for exotic heavy quarks across arbitrary branching fractions and different vector-like quark models using CMS data.

Findings

Excludes T quarks below 480-550 GeV depending on model

Excludes B quarks below 480 GeV for singlets

Excludes vector-like quarks below 550-640 GeV depending on model

Abstract

General limits on exotic heavy quarks T, B and X with masses above 300 GeV are presented for arbitrary branching fractions of T=>Wb, T=>Zt, T=>Ht, B=>Wt, B=>Zb, B=>Hb and X=>Wt. The results are based on a CMS search in final states with three isolated leptons (electron or muon) or two isolated leptons with the same electric charge. Exotic heavy quark pair production through the strong interaction is considered. In the context of vector-like quark models, T quarks with a mass mT < 480 GeV and mT < 550 GeV are excluded for weak isospin singlets and doublets, respectively, and B quarks with a mass mB < 480 GeV are excluded for singlets, all at 95% confidence level. Mass limits at 95% confidence level for T and B singlets, (T,B) doublets and (X,T) doublets are presented as a function of the corresponding heavy quark masses. For equal mass mT = mB and mX = mT vector-like quarks are excluded at 95% confidence level with masses below 550 GeV for T and B singlets, 640 GeV for a (T,B) doublet and 640 GeV for a (X,T) doublet.