Rare top decay t-> c l+l- as a probe of new physics

TL;DR

This paper investigates the rare top decay t-> c l+l- as a potential indicator of new physics, specifically within the Left-Right Symmetric Model featuring a Z' boson that facilitates flavor-changing neutral currents at tree level.

Contribution

It analyzes the rare decay within a specific Standard Model extension, providing predictions for branching ratios influenced by a new Z' gauge boson.

Findings

Branching ratio estimated at ~10^{-13} for Z' masses between 1 and 3 TeV.

Decay occurs via flavor-changing neutral currents at tree level.

Model demonstrates potential for new physics signals in rare top decays.

Abstract

The rare top decay t-> c l+l-, which involves flavor violation, is studied as a possible probe of new physics. This decay is analyzed with the simplest Standard Model extensions with additional gauge symmetry formalism. The considered extension is the Left-Right Symmetric Model, including a new neutral gauge boson Z' that allows to obtain the decay at tree level through Flavor Changing Neutral Currents (FCNC) couplings. The neutral gauge boson couplings are considered diagonal but family non-universal in order to induce these FCNC. We find the $BR(t-> c l+l-)~10^{-13} for a range 1 TeV < M_{Z'} < 3 TeV.