Rare top decay and CP violation in THDM

Abstract

We discuss the formalism of two Higgs doublet model type III with CP violation from CP-even CP-odd mixing in the neutral Higgs bosons. The flavor changing interactions among neutral Higgs bosons and fermions are presented at tree level in this type of model. These assumptions allow the study rare top decays mediated by neutral Higgs bosons, particularly we are interested in $t\to c{l}^{+}{l}^{-}$. For this process we estimated upper bounds of the branching ratios $\text{Br}(t\to c{\tau }^{+}{\tau }^{-})$ of the order of $10^{-9}\sim 10^{-7}$ for a neutral Higgs boson mass of 125 GeV and $\tan \beta =1$, 1.5, 2, 2.5. For the case of $t\to c{\tau }^{+}{\tau }^{-}$ the number of possible events is estimated from 1 to 10 events which could be observed in future experiments at LHC with a luminosity of 300 ${\text{fb}}^{-1}$ and 14 GeV for the energy of the center of mass. Also we estimate that the number of events for the process $t\to c{l}^{+}{l}^{-}$ in different scenarios is of order of $2500$.

Comments: 8 pages, 5 figures