Probing the Type-II Seesaw Mechanism through the Production of Higgs Bosons at a Lepton Collider

TL;DR

This paper explores the potential to detect doubly-charged Higgs bosons predicted by the Type-II seesaw mechanism at future electron-positron colliders, analyzing different energy regimes and decay signatures to identify discovery prospects.

Contribution

It provides a detailed analysis of Higgs boson production and decay at different collider energies, including substructure techniques for background reduction and discovery potential.

Findings

Doubly-charged Higgs bosons with masses 160-172 GeV can be discovered at 380 GeV.

Heavy Higgs bosons with masses 800-1120 GeV can be detected at 3 TeV.

Light Higgs bosons are accessible during initial collider runs.

Abstract

We investigate the production and decays of doubly-charged Higgs bosons for the Type-II seesaw mechanism at an $e^{+} e^{-}$ collider with two center of mass energies, $\sqrt{s}=380$ GeV and 3 TeV, and analyze the fully hadronic final states in detail. Lower mass ranges can be probed during the 380 GeV run of the collider, while high mass ranges, which are beyond the 13 TeV Large Hadron Collider discovery reach, can be probed with $\sqrt{s}=3$ TeV. For such a heavy Higgs boson, the final decay products are collimated, resulting in fat-jets. We perform a substructure analysis to reduce the background and find that a doubly-charged Higgs boson in the mass range 800-1120 GeV can be discovered during the 3 TeV run, with integrated luminosity $\mathcal{L} \sim 95\, \rm{fb}^{-1}$ of data. For 380 GeV center of mass energy, we find that for the doubly-charged Higgs boson in the range 160-172 GeV, a $5\sigma$ significance can be achieved with only integrated luminosity $\mathcal{L} \sim 24 \, \rm{fb}^{-1}$. Therefore, a light Higgs boson can be discovered immediately during the run of a future $e^{+} e^{-}$ collider.