# Production of heavy Higgs bosons and decay into top quarks at the LHC. II: Top-quark polarization and spin correlation effects

## TL;DR

This paper studies how heavy Higgs bosons in extended models affect top-quark pair production and decay at the LHC, focusing on spin observables to improve detection sensitivity.

## Contribution

It demonstrates that analyzing top-spin observables in specific invariant mass bins enhances the ability to detect heavy Higgs resonances at the LHC.

## Key findings

- Top-spin observables are sensitive to heavy Higgs effects.
- NLO QCD and weak corrections are significant in analysis.
- Invariant mass binning improves resonance detection.

## Abstract

We analyze, within several parameter scenarios of type-II two-Higgs doublet extensions of the standard model, the impact of heavy neutral Higgs-boson resonances on top-quark pair production and their subsequent decay to dileptonic final states at the LHC (13 TeV). In particular, we investigate the effects of heavy Higgs bosons on top-spin observables, that is, the longitudinal top-quark polarization and top-quark spin correlations. We take into account NLO QCD as well as weak interaction corrections and show that top-spin observables, if evaluated in judiciously chosen top-quark pair invariant mass bins, can significantly enhance the sensitivity to heavy Higgs resonances in top-quark pair events.