Loop induced $H^\pm \rightarrow W^\pm Z$ decays in the aligned two-Higgs-doublet model

TL;DR

This paper provides a detailed one-loop analysis of the rare decay $H^\u00b0 ightarrow W^\u00b0 Z$ in the aligned two-Higgs-doublet model, highlighting conditions for significant enhancement within experimental constraints.

Contribution

It offers the first comprehensive one-loop calculation of this decay in the model, considering all relevant experimental and theoretical constraints.

Findings

Branching ratio can reach  10^{-3} with large mass splitting.

Maximum branching ratio occurs for specific mass and parameter configurations.

Decay potentially observable at the high luminosity LHC.

Abstract

We present a complete one-loop computation of the $H^\pm \rightarrow W^\pm Z$ decay in the aligned two-Higgs-doublet model. The constraints from the electroweak precision observables, perturbative unitarity, vacuum stability and flavour physics are all taken into account along with the latest Large Hadron Collider searches for the charged Higgs. It is observed that a large enhancement of the branching ratio can be obtained in the limit where there is a large splitting between the charged and pseudo-scalar Higgs masses as well as for the largest allowed values of the alignment parameter $\varsigma_u$. We find that the maximum possible branching ratio in the case of a large mass splitting between $m_{H^\pm}$ and $m_A$ is $\approx 10^{-3}$ for $m_{H^\pm} \in (200,700)$ GeV which is in the reach of the high luminosity phase of the Large Hadron Collider.