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

TL;DR

This paper explores the potential of a 100 TeV proton-proton collider to discover and analyze scalar triplet particles in the Type-II seesaw model, focusing on specific production channels and Higgs portal couplings.

Contribution

It identifies promising discovery channels and methods for measuring Higgs portal couplings in the Type-II seesaw scalar triplet model at a future collider.

Findings

$H^{oxed{++}}H^{oxed{--}}$ and $H^{oxed{\pm\pm}}H^{oxed{\mp}}$ channels are promising for discovery.

The $H^{oxed{\pmoldsymbol{\pmoldsymbol{ ext{}}}}}H^{oxed{\mp}}$ channels can determine Higgs portal couplings $oldsymbol{\lambda_4}$ and $oldsymbol{\lambda_5}$.

These channels complement indirect measurements from Higgs decay rates.

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.