Below-threshold CP-odd Higgs boson search via A → Z⁎h at the LHC

Abstract

We study the process qq¯,gg→A→Z⁎h in a 2-Higgs Doublet Model Type-II where the mass of the CP-odd Higgs state A is lower than the rest mass of the Z and h particles (the latter being the Standard Model-like Higgs state discovered at the Large Hadron Collider in 2012), i.e., mA<mZ+mh≈215 GeV. This is a mass range which is not being currently tested by ATLAS and CMS, yet we show that there can be sensitivity to it already during Runs 2 & 3, assuming leptonic decays of the gauge boson and bottom-antibottom quark ones for the Higgs boson.