Exotic Higgs Decay via Charged Higgs

TL;DR

This paper investigates alternative decay channels involving charged Higgses in extended Higgs models, setting limits on production cross sections and exploring their implications in the Type II 2HDM parameter space.

Contribution

It introduces and analyzes two novel Higgs decay channels involving charged Higgses, providing experimental limits and parameter space interpretations.

Findings

Limits on cross sections vary from 10 to 80 fb depending on mass and channel.

The $A/H^0 ightarrow W^ op H^ op$ channel offers strong sensitivity in certain parameter regions.

The $H^0 ightarrow H^+ H^-$ channel can cover most of the parameter space for $H^0$.

Abstract

The most common search channel for heavy neutral Higgses in models with an extension of the Standard Model Higgs sector is $A/H^0\rightarrow \tau\tau$, which becomes ineffective when new decay modes of $A/H^0$ open. In this paper, we analyzed two such channels involving charged Higgses in the final states: $A/H^0 \rightarrow W^\pm H^\mp$ and $H^0 \rightarrow H^+H^-$. With the consequent decay of $H^\pm\rightarrow \tau\nu$, we found that the limits for $\sigma\times{BR}(gg \rightarrow A/H^0 \rightarrow W^\pm H^\mp)\times {BR}(H^\pm \rightarrow \tau \nu)$ vary from 30 to 10 fb for $m_{A/H^0}$ between 300 and 1000 GeV for 95% C.L. exclusion, and about 80 to 30 fb for 5$\sigma$ discovery. For $H^+H^-$ mode, 95% C.L. limits on $\sigma\times {BR}(gg\to H^0\to H^+ H^-)\times {BR}^2(H^\pm\to \tau\nu)$ vary from 9 to 4 fb for $m_{H^0}$ between 400 and 1000 GeV, while the 5$\sigma$ reach is about 20 to 10 fb. We further interpret the cross section limits in the Type II 2HDM parameter space. While $A\rightarrow W^\pm H^\mp$ offers great sensitivity in both $\sin(\beta-\alpha)$ versus $\tan\beta$ and $m_A$ versus $\tan\beta$ parameter space, $H^0\rightarrow H^+ H^-$ can cover most of the parameter space for $H^0$. Reach in $H^0\rightarrow W^\pm H^\mp$ is more limited, especially for $m_{H^0}>2 m_{H^\pm}$. It is, however, complementary to $H^0\rightarrow H^+ H^-$ when ${BR}(H^0\rightarrow H^+ H^-)$ is accidentally suppressed.