Testing the Higgs triplet model with the mass difference at the LHC

TL;DR

This paper explores how the Higgs triplet model with specific mass differences among scalar bosons can be tested at the LHC, focusing on cascade decay signatures to distinguish it from other models.

Contribution

It introduces a method to identify the Higgs triplet model via cascade decays related to mass differences, especially for the case where the doubly-charged scalar is the heaviest.

Findings

Cascade decay channels can reveal the mass hierarchy of scalar bosons.

The model can be distinguished from other doubly-charged scalar models through specific decay signatures.

Mass spectrum determination enables testing and differentiation of the Higgs triplet model at the LHC.

Abstract

In general, there can be mass differences among scalar bosons of the Higgs triplet field with the hypercharge of Y=1. In the Higgs triplet model, when the vacuum expectation value $v_\Delta$ of the triplet field is much smaller than that $v$ ($\simeq 246$ GeV) of the Higgs doublet field as required by the electroweak precision data, a characteristic mass spectrum $ m_{H^{++}}^2-m_{H^+}^2\simeq m_{H^+}^2-m_{\phi^0}^2(\equiv \xi)$ appears, where $m_{H^{++}}$, $m_{H^+}$, $m_{\phi^0}$ are the masses of the doubly-charged ($H^{++}$), the singly-charged ($H^+$) and the neutral ($\phi^0=H^0$ or $A^0$) scalar bosons, respectively. It should be emphasized that phenomenology with $\xi\neq 0$ is drastically different from that in the case with $\xi=0$ where the doubly-charged scalar boson decays into the same sign dilepton $\ell^+\ell^+$ or the diboson $W^+W^+$ depending on the size of $v_\Delta$. We find that, in the case of $\xi > 0$, where $H^{++}$ is the heaviest, $H^{++}$ can be identified via the cascade decays such as $H^{++}\to H^+W^{+(*)}\to \phi^0 W^{+(*)}W^{+(*)}\to b\bar{b}\ell^+\nu\ell^+\nu$. We outline how the Higgs triplet model can be explored in such a case at the LHC. By the determination of the mass spectrum, the model can be tested and further can be distinguished from the other models with doubly-charged scalar bosons.