# Heavy Higgs Bosons at the LHC Upgrade

## TL;DR

This paper assesses the discovery prospects of heavy Higgs bosons at the 27 TeV LHC upgrade, analyzing various production and decay channels within the Type-II Two Higgs Doublet Model to guide future experimental searches.

## Contribution

It provides a comprehensive evaluation of multiple production and decay channels for heavy Higgs bosons at the upgraded LHC, highlighting electroweak pair production as a complementary discovery avenue.

## Key findings

- Heavy neutral Higgses can be observed via $ au^+ au^-$, $W^+W^-$, and $ZZ$ channels.
- Charged Higgses can be detected through associated production with top quarks.
- Electroweak Higgs pair production offers additional discovery potential.

## Abstract

We evaluate the discovery potential for the heavy Higgs bosons at the LHC energy upgrade with $\sqrt{s}=27$ TeV. We take degenerate mass spectrum and assume near the alignment limit in the Type-II Two Higgs Doublet Model for illustration. We explore the observability of the heavy neutral Higgs bosons by examining the leading decay channel $H^0/A^0\to \tau^+\tau^-$ and the clean signals from $H^0\to W^+W^-, ZZ$ via gluon-gluon fusion production. The associated production of a top quark and a charged Higgs boson via $gb\to t H^\pm$ is adopted to predict the discovery potential of heavy charged Higgses. We also emphasize the potential importance of the electroweak production of Higgs boson pairs, i.e. $pp\to W^\ast \to H^\pm A^0$ and $pp\to Z^\ast/\gamma^\ast \to H^+ H^-$. They are only governed by pure electroweak gauge couplings and can provide complementary information to the conventional signals in the determination of the nature of the Higgs sector.