Searching for heavy Higgs bosons in the $t \bar t Z$ and $t b W$ final states

TL;DR

This paper investigates the potential to discover heavy Higgs bosons in specific final states at the 14 TeV LHC within two-Higgs doublet models, providing analysis strategies and sensitivity estimates.

Contribution

It develops realistic analysis strategies for heavy Higgs searches in $t\bar t Z$ and $t b W$ channels and evaluates their discovery potential at the LHC.

Findings

$t\bar t Z$ searches can constrain low $\tan \beta$ for Higgs masses 450-1150 GeV with 300 fb$^{-1}$.

Future $t b W$ searches can probe parts of the parameter space.

Constraints depend on systematic uncertainties of the $t\bar t$ background shape.

Abstract

In the context of two-Higgs doublet models, we explore the possibility of searching for heavy Higgs bosons in the $t \bar t Z$ and $t bW$ final states. We develop realistic analyses strategies and in the case of the $t \bar t Z$ channel provide a detailed evaluation of the new-physics reach at the 14 TeV LHC. We find that already with an integrated luminosity of $300 \, {\rm fb}^{-1}$ searches for the $t \bar t Z$ signature can provide statistically significant constraints at low values of $\tan \beta$ for heavy Higgs masses in the range from around $450 \, {\rm GeV}$ to $1150 \, {\rm GeV}$. Future searches for heavy Higgses in the $tbW$ final state are also expected to be able to probe parts of this parameter space, though the precise constraints turn out to depend sensitively on the assumed systematics on the shape of the $t \bar t$ background.