Testing flavor-changing neutral currents in the rare decays t->cViVj

TL;DR

This paper analyzes rare top quark decays involving flavor-changing neutral currents within the Standard Model and a two-Higgs doublet model, highlighting potential observable differences at the LHC.

Contribution

It compares FCNC top decays in the SM and 2HDM, revealing possible sizable branching ratios and differing suppression patterns.

Findings

SM predicts extremely small branching ratios

2HDM allows branching ratios around 10^(-5)

FCNC decay modes may not be equally suppressed

Abstract

We discuss the Flavor-Changing Neutral Current (FCNC) decays of the top quark t -> c Vi Vj (Vi=gamma, Z, g) in the framework of the Standard Model (SM) and in a two-higgs doublet model (2HDM) with tree-level FCNC couplings. While in the SM the expected branching ratios are extremelly small, in the 2HDM they may be sizable, of order 10^(-5) - 10^(-5), and thus accesible at the CERN LHC. We conclude with the interesting observation that the FCNC decay modes may not be equally suppressed as their corresponding decays t ->c Vi in this 2HDM.