Top-Assisted Di-Higgs boson Production Motivated by Baryogenesis

Abstract

We study top-assisted di-Higgs production via $cg\to tH\to thh$, where $h$ is the 125 GeV scalar boson, and $H$ is the $CP$-even heavy Higgs. The context is the two Higgs doublet model without a $Z_2$ symmetry, where the extra Yukawa coupling ${\rho }_{tc}$ generates $tH$ production, with the extra top Yukawa ${\rho }_{tt}\simeq 0$ to avoid $gg\to H$ constraints. We find that discovery is possible for $m_H$ around 300 GeV or so at the LHC, but would need finite $h$-$H$ mixing angle $\cos \gamma$ to allow for finite ${\lambda }_{Hhh}$ coupling, and ${\rho }_{tc}$ also needs to be not too small. A sizable ${\rho }_{tc}$ could drive electroweak baryogenesis, which further motivates the search.

Comments: matches with published version