Rare top decay $t \rightarrow c \gamma$ with flavor changing neutral scalar interactions in two Higgs doublet model

TL;DR

This paper investigates the rare top quark decay $t ightarrow c \gamma$ within the Two Higgs Doublet Model Type III, analyzing its branching ratio and event rate considering flavor-changing neutral scalar interactions and experimental constraints.

Contribution

It provides a detailed calculation of the $t ightarrow c \gamma$ decay rate in the 2HDM Type III, including neutral Higgs mixing effects and realistic parameter constraints.

Findings

Branching ratio $Br(t ightarrow c \\gamma) \\sim 10^{-6}$ for specific parameters.

Estimated 10 to 100 events at 300 fb^{-1} luminosity.

Decay rate sensitive to Higgs mixing angles and $ an\beta$.

Abstract

Models beyond the Standard Model with extra scalars have been highly motivated by the recent discovery of a Higgs boson. The Two Higgs Doublet Model Type III considers the most general case for the scalar potential, allowing mixing between neutral CP-even and CP-odd scalar fields. This work presents the results of the study on the $t\rightarrow c\gamma$ decay at one loop level if neutral flavor changing is generated by top-charm-Higgs coupling given by the Yukawa matrix. For instance, a value for the branching ratio $Br(t\rightarrow c\gamma)\sim 10^{-6}$ for $\tan\beta=2.5$ and general neutral Higgs mixing parameters, $1.16\leq\alpha_1\leq1.5$, $-0.48\leq\alpha_2\leq-0.1$. The number of events for the $t\rightarrow c \gamma$ decay with an integrated luminosity of 300 $fb^{-1}$ is estimated as $10\lesssim N_{Eff}\lesssim 100$ for the parameters of the model constrained by experimental data.