Top quark FCNCs in extended Higgs sectors

TL;DR

This paper explores the potential to detect rare flavor-violating top quark decays induced by scalar singlets in extended Higgs models at current and future colliders, proposing new search strategies and estimating discovery reach.

Contribution

It introduces novel search strategies for flavor-violating top decays in models with scalar singlets and estimates the probing scales at various collider energies.

Findings

Scales of 10-50 TeV can be probed at the LHC.

Future colliders at 27 TeV and 100 TeV can improve sensitivity by factors of 1.5 and 3.

Rare top decays can surpass Higgs contributions in certain models.

Abstract

The large number of top quarks produced at the LHC and possible future hadron colliders allows to study rare decays of this particle. In many well motivated models of new physics, for example in non-minimal composite-Higgs models, the existence of scalar singlets can induce new flavor-violating top decays surpassing the Higgs contribution by orders of magnitude. We study the discovery prospects of rare top decays within such models and develop new search strategies to test these interactions in top pair-produced events at the LHC. We demonstrate that scales as large as $10$--$50$ TeV can be probed. Improvements by factors of $\sim 1.5$ and $\sim 3$ can be obtained at $\sqrt{s} = 27$ TeV and $\sqrt{s} = 100$ TeV colliders.