Probing the general 2HDM with flavor violation through $A \to ZH$

We investigate the LHC discovery prospects for a second Higgs doublet through $A \to ZH$ weak decay. The latter is identified as the $\textit{smoking gun signature}$ of two Higgs doublet models (2HDMs) with first-order electroweak (EW) phase transition, a necessary condition for EW baryogenesis. In the general 2HDM (G2HDM) that has flavor-changing neutral Higgs couplings, $H$ may decay dominantly via $t\bar c + \bar tc$ final states, giving rise to trilepton signals. By a phenomenological analysis, we show that $A \to ZH$ in $\ell^+ \ell^- t\bar c$ or $\ell^+ \ell^- \bar t c$ final states could be a promising probe of G2HDM at the LHC with flavor violation.