Multi-top signals of vectorlike quarks at the LHC

TL;DR

This paper explores the potential for observing multi-top quark events, including up to 10 tops, at the LHC as signals of new TeV-scale particles in specific vectorlike quark models.

Contribution

It introduces a novel model predicting high-multiplicity top events at the LHC, including cascade decays leading to up to 10 top quarks, and discusses their distinctive signatures.

Findings

Events with 6 or more top quarks could be observed at the LHC.

The dominant signal may be 8 top quarks, producing spectacular multi-lepton and b-jet signatures.

Possible cross section measurements could determine masses of new particles.

Abstract

We point out that events with 6 or more top quarks may be observed at the LHC if certain particles exist at the TeV scale. In a model where a vectorlike quark of charge 2/3 decays into a top quark and a pseudoscalar particle, which subsequently decays into a top-antitop pair, the LHC production cross section for events with 6 top quarks may be above 10 fb. If the pseudoscalar is part of a complex scalar field, then longer cascade decays, involving the scalar partner, may lead to events with 8 or even 10 top quarks. We show that for a region of parameter space the dominant LHC signal in this model is 8 top quarks (i.e., four $t\bar t $ pairs). The ensuing signals would be spectacular, including many leptons and $b$ jets. A discovery in that case would allow several cross section measurements that may determine the masses of all three new particles.