Two-Higgs-Doublet Type-II Seesaw Model

TL;DR

This paper explores a two-Higgs-doublet extension of the type-II seesaw model, revealing new decay patterns and interactions of doubly charged Higgs bosons influenced by scalar potential mixing, with implications for collider searches.

Contribution

It introduces a novel two-Higgs-doublet type-II seesaw model with significant charged Higgs mixing, leading to unique decay channels and quark couplings not present in previous models.

Findings

Distinct decay patterns for doubly charged Higgs due to mixing.

New open channels involving charged Higgs and W bosons.

Enhanced collider search strategies for doubly charged Higgs.

Abstract

Motivated by the new observed scalar boson of 126 GeV at ATLAS and CMS, various phenomena in two-Higgs-doublet model (THDM) are investigated broadly in the literature. For considering the model that possesses a solution to the massive neutrinos, we study the simplest extension of conventional type-II seesaw model to two Higgs doublets. We find that the new interactions in the scalar potential cause the sizable mixture of charged Higgses in triplet and doublet. As a result, we have a completely different decay pattern for doubly charged Higgs ($\delta^{\pm\pm}$), even the vacuum expectation value (VEV) of Higgs triplet is at GeV level, which is limited by the precision measurement for $\rho$-parameter. For illustrating the new characters of the model, we study the influence of new interactions on the new open channels $\delta^{++}\to ( H^+_1 W^{+^{(*)}}, H^+_1 H^+_1)$ with $H^+_1$ being the lightest charged Higgs. Additionally, due to the new mixing effect, the triplet charged Higgs could couple to quarks in the model; therefore, the search for $\delta^{++}$ via $\delta^{++}\to tb W^+ \to b \bar b W^+ W^+$ by mediated $H^+_{1}$ becomes significant.