Type-II Seesaw Scalar Triplet Model at a 100 TeV $pp$ Collider: Discovery and Higgs Portal Coupling Determination

Abstract

We investigate the collider phenomenology of the scalar triplet particles in the Type-II seesaw model at a 100 TeV $pp$ collider. Depending on triplet vacuum expectation value $v_{\Delta }$, the dominant discovery channels could be $H^{++}{H}^{--}$ and $H^{\pm \pm }{H}^{\mp }$. We find the $H^{\pm \pm }{H}^{\mp }\to W^{\pm }{W}^{\pm }h{W}^{\mp }/{\ell }^{\pm }{\ell }^{\pm }h{W}^{\mp }$ channels are promising for both model discovery at relatively large $v_{\Delta }$ and determination of the Higgs portal couplings ${\lambda }_4$ and ${\lambda }_5$. We also find that these two channels are complementary to indirect determination of ${\lambda }_4$ from future precise measurements on $h\to \gamma \gamma$ decay rate. Together with pair production of the doubly-charged Higgs subsequently decaying into same-sign di-leptons, the $H^{\pm \pm }{H}^{\mp }$ channels have the potential to cover a significant portion of the parameter space of the Type-II seesaw complex scalar triplet model.

35 pages, 13 figures