Rare Top Decay &amp;lt;i&amp;gt;t&amp;lt;/i&amp;gt; &amp;amp;rarr;&amp;lt;i&amp;gt;c&amp;amp;gamma;&amp;lt;/i&amp;gt; in General THDM-III

R Gaitán-Lozano,R Martinez,J H Montes De Oca

doi:10.4236/jqis.2017.72006

Abstract

We study the decay t → cγ with flavor-changing neutral interactions in scalar sector of the type III Two Higgs Doublet Model (THDM-III) with mixing between neutral scalar fields as a result of considering the most general scalar potential. The branching ratio of the decay Br (t → cγ) is calculated as function of the mixing parameters and masses of the neutral scalar fields. We obtain a Br (t → cγ) of the order of 10−8 for the considered regions of the mixing parameters. Finally, one upper bound for the possible events is estimated to be n=18 by assuming an expected luminosity of the order of 300 fb−1.

Highlights

A sensitive test for new physics is the processes of the top quark due to large mass
We study the decay t → cγ with flavor-changing neutral interactions in scalar sector of the type III Two Higgs Doublet Model (THDM-III) with mixing between neutral scalar fields as a result of considering the most general scalar potential
The distinctive characteristic of 2HDM-III is the presence of flavor-changing neutral scalar interactions (FCNSI), which requires a certain mechanism in order to suppress them, for instance, one can impose a certain texture for the Yukawa couplings [17], which will predict a pattern of FCNSI Higgs couplings

Summary

Introduction

A sensitive test for new physics is the processes of the top quark due to large mass. The distinctive characteristic of 2HDM-III is the presence of FCNSI, which requires a certain mechanism in order to suppress them, for instance, one can impose a certain texture for the Yukawa couplings [17], which will predict a pattern of FCNSI Higgs couplings. Within all those models (2HDM-I, II, III) [18], the Higgs doublets couple with all fermion families, with a strength proportional to the fermion masses, modulo other parameters. We calculate the the BR for the decay t → cγ in the framework of the general 2HDM

The General Two-Higgs-Dublet Model Type III

Mixing Parameters and Numerical Results

Conclusions