SM Higgs boson and $t\to cZ$ decays in the 2HDM type III with CP violation

Abstract

We compute the contributions to rare top decays $t\to cZ$ and $t\to c{h}_1$ from the scalar sector in the 2HDM type III with CP violation, where $h_1$ is the Standard Model Higgs boson. The branching ratio for $BR(t\to cZ)$ and $BR(t\to c{h}_1)$ are obtained as a function of the model parameters. In particular, the $BR(t\to cZ)$ can increase its value up to $10^{-3}$ for $\tan \beta =1$ and masses for the additional Higgs bosons of $m_{h_2,h_3,H^{\pm }}\sim 0.5$ TeV. Meanwhile $BR(t\to c{h}_1)$ can reach values of the order of $\sim 10^{-2}$. We constrain the model parameters (mixing angles of the neutral scalar fields in the CP violation context and $\tan \beta$) using the reported values of the signal strengths $R_{XX}$ and $b\to s\gamma$ process.

Comments: 19 pages, 12 figures