Doubly-charged Higgs bosons in the diboson decay scenario at the ILC

TL;DR

This paper explores the detection prospects of doubly-charged Higgs bosons in the Higgs Triplet Model at the ILC, focusing on the scenario where these particles decay into same-sign dibosons, which is less constrained by current experiments.

Contribution

It analyzes the phenomenology and detection strategies for doubly-charged Higgs bosons decaying into dibosons at the ILC, especially in the less-explored parameter region with larger triplet VEV.

Findings

Current collider bounds do not exclude light $H^{\

Detection strategies at the ILC are proposed for the diboson decay scenario of $H^{\

Abstract

The Higgs Triplet Model (HTM) is one of important examples for extended Higgs sectors, because tiny neutrino masses can be simply explained. Unlike the canonical type-I seesaw model, a scale of new particles can be taken as $\mathcal{O}(100)$ GeV keeping an enough amount of production cross section for direct searches at collider experiments. In the HTM, there appear doubly-charged Higgs bosons $H^{\pm\pm}$, and detection of them is a key to probe the model. The decay property of $H^{\pm\pm}$ depends on the magnitude of the vacuum expectation value of the triplet field $v_\Delta$. When $v_\Delta$ is smaller than about 1 MeV, $H^{\pm\pm}$ can mainly decay into the same-sign dilepton, and the lower mass limit for $H^{\pm\pm}$ had been taken to be about 400 GeV at the LHC. On the other hand, if $v_\Delta$ is larger than about 1 MeV, $H^{\pm\pm}$ can mainly decay into the same-sign diboson. In this case, the mass bound cannot be applied, so that the scenario based on light $H^{\pm\pm}$ is still possible. In this talk, we discuss the phenomenology of the same-sign diboson decay scenario of $H^{\pm\pm}$. First, we review the mass bound from the current collider experiments given in Ref. \cite{KYY}. We then discuss the strategy for detection of $H^{\pm\pm}$ at the ILC.