Abstract
We study top-assisted di-Higgs production via $cg\ensuremath{\rightarrow}tH\ensuremath{\rightarrow}thh$, 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 ${\ensuremath{\rho}}_{tc}$ generates $tH$ production, with the extra top Yukawa ${\ensuremath{\rho}}_{tt}\ensuremath{\simeq}0$ to avoid $gg\ensuremath{\rightarrow}H$ constraints. We find that discovery is possible for ${m}_{H}$ around 300 GeV or so at the LHC but would need finite $h\ensuremath{-}H$ mixing angle $\mathrm{cos}\ensuremath{\gamma}$ to allow for finite ${\ensuremath{\lambda}}_{Hhh}$ coupling, and ${\ensuremath{\rho}}_{tc}$ also needs to be not too small. A sizable ${\ensuremath{\rho}}_{tc}$ could drive electroweak baryogenesis, which further motivates the search.
Highlights
The highlight at the LHC so far is the discovery of the 125 GeV scalar boson h [1] in 2012, which resembles rather closely [2] the Higgs boson of the Standard Model (SM)
We explore a novel possibility with new physics, that of resonant hh production in association with a top quark
A second process depends on the flavor-changing neutral Higgs (FCNH) tcH coupling, ρtc, whereby one can have cg → tH → thh
Summary
The highlight at the LHC so far is the discovery of the 125 GeV scalar boson h [1] in 2012, which resembles rather closely [2] the Higgs boson of the Standard Model (SM). The existence of extra diagonal Yukawa coupling ρtt of the exotic CP-even neutral Higgs boson H means that one could have gg → H → hh production through a triangle top-quark loop. We focus on this process, exploiting the extra top quark to investigate possible prospects at the LHC. In exploring [13] the prospect for a lighter pseudoscalar A boson around 300 GeV, in the face of direct search bounds, we opted to turn off ρtt, noting that ρtc ∼ 1 would still offer an alternative mechanism [14] for EWBG, and it is interesting in itself. We find that thh discovery is possible at the HL-LHC for relatively light H, where the associated top quark gives extra handle on background reduction.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have