Pseudoscalar decays to gauge bosons at the LHC and at a future 100 TeV collider

TL;DR

This paper investigates the potential to detect pseudoscalar decays into gauge bosons within two Higgs doublet models at the LHC and a future 100 TeV collider, highlighting the impact of model extensions on observability.

Contribution

It provides a comparative analysis of pseudoscalar decay signals in 2HDM and 2HDM+VLQ models at current and future colliders, emphasizing the detectability of the $Z$-boson decay channel.

Findings

$A o ZZ$ decay is hard to detect in 2HDM at 100 TeV collider.

$A o ZZ$ decay can be probed at the LHC in 2HDM+VLQ.

Decays of pseudoscalar into gauge bosons are analyzed in the alignment limit.

Abstract

We discuss the search for a CP-odd scalar decaying into gauge bosons in the framework of a CP-conserving two-Higgs doublet model (2HDM) and of a 2HDM extended with a vector-like quark (VLQ) at the Large Hadron Collider and at a future 100 TeV collider. The rate of decay of a pseudoscalar to $Z$-bosons could be important to ascertain the CP-nature of the scalars in the model. In the 2HDM $A \to ZZ$ will be extremely hard to detect even at a future 100 TeV $pp$ collider while in the 2HDM+VLQ this decay can be probed even during the present LHC run. We further discuss all decays of the pseudoscalar into gauge bosons at the LHC and at a future 100 TeV collider in the alignment limit where the lightest scalar is the 125 GeV Higgs with SM-like couplings to the fermions and gauge bosons.