Top-Higgs Associated Production involving {\boldmath ${A^0},\, {H^0}$} with Mass at 300 GeV

Abstract

We advocate two Higgs doublet model without $Z_2$ symmetry, and focus on the extra top Yukawa couplings $\rho_{tt}$ and $\rho_{tc}$. We show that $A^0$ and $H^0$ bosons are still allowed at 300 GeV mass, where $cg \to tA^0$, $tH^0$ can lead to $tt\bar c$ same-sign top, or top-assisted di-Higgs $th^0h^0$ signatures, resp. As bonus material, we explore the constraint provided by current 4-top search, but advocate direct search for triple-top generated by $cg \to tH^0/A^0 \to tt\bar t$ for $H^0,\, A^0$ above $t\bar t$ threshold, and offer some insight on the mild but intriguing "excess" found by CMS in $gg \to A^0 \to t\bar t$ at 400 GeV.