Heavy Higgs boson resonances and their decay into top quarks at the LHC

TL;DR

This paper studies how heavy neutral Higgs bosons in a two-Higgs-doublet model affect top-quark pair production at the LHC, including NLO QCD corrections and interference effects, providing detailed phenomenological insights.

Contribution

It presents the first NLO QCD calculation of heavy Higgs resonance interference with SM top pair production in the 2HDM, including CP-violating scenarios.

Findings

Interference effects significantly alter top pair invariant mass distributions.

NLO corrections increase the predicted cross sections by a K-factor.

Results help distinguish heavy Higgs signals from SM background.

Abstract

We investigate, within the type-II two-Higgs-doublet extension of the standard model (SM), the impact of heavy neutral Higgs boson resonances with unsuppressed Yukawa couplings to top quarks on top-quark pair production at the LHC at next-to-leading order (NLO) in the strong coupling constant. We take into account the resonant Higgs boson contributions, the non-resonant SM $t\bar{t}$ continuum and the interference of these two contributions. The NLO QCD corrections to heavy Higgs production and the interference contributions are calculated in the large top-quark mass ($m_t$) limit, including an effective K-factor rescaling. Our evaluation of the QCD-Higgs interference is focused on the Higgs resonance region. Using representative CP-conserving as well as CP-violating parameter scenarios phenomenological results are presented for different observables.