Top Decays with Flavor Changing Neutral Higgs Interactions at the LHC

Abstract

We investigate the prospects for discovering a top quark decaying into one light Higgs boson along with a charm quark in top quark pair production at the CERN Large Hadron Collider (LHC). A general two Higgs doublet model is adopted to study the signature of flavor changing neutral Higgs decay $t\to c{\varphi }^0$, %or $\bar{t}\to \bar{c}{\varphi }^0$ where ${\varphi }^0$ could be CP-even ($H^0$) or CP-odd ($A^0$). The dominant physics background is evaluated with realistic acceptance cuts as well as tagging and mistagging efficiencies. For a reasonably large top-charm-Higgs coupling (${\lambda }_{tc}/{\lambda }_t\text{agt}0.09$), the abundance of signal events and the %that our acceptance cuts reduction in physics background allow us to establish a $5\sigma$ signal for $M_{\varphi }\sim 125$ GeV at the LHC with a center of mass energy ($\sqrt{s}$) of 8 TeV and an integrated luminosity of 20 fb${}^{-1}$. The discovery potential will be greatly enhanced with the full energy of $\sqrt{s}=14$ TeV.

Comments: Revised version to appear in Physics Letters B