Search for a heavy pseudoscalar Higgs boson decaying into a 125 GeV Higgs boson and a Z boson in final states with two tau and two light leptons at $\sqrt{s} =$ 13 TeV

TL;DR

This paper reports a search for a heavy pseudoscalar Higgs boson decaying into a 125 GeV Higgs and a Z boson, using 13 TeV proton-proton collision data, setting upper limits on production cross sections without observing a significant excess.

Contribution

It provides the first constraints on the pseudoscalar Higgs boson decaying into Zh in final states with tau and light leptons at 13 TeV, extending previous searches.

Findings

No significant excess observed above background.

Upper limits set on gluon fusion production cross section times branching ratio.

Constraints placed on parameters of the minimal supersymmetric standard model.

Abstract

A search is performed for a pseudoscalar Higgs boson, A, decaying into a 125 GeV Higgs boson h and a Z boson. The h boson is specifically targeted in its decay into a pair of tau leptons, while the Z boson decays into a pair of electrons or muons. A data sample of proton-proton collisions collected by the CMS experiment at the LHC at $\sqrt{s} =$ 13 TeV is used, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. No excess above the standard model background expectations is observed in data. A model-independent upper limit is set on the product of the gluon fusion production cross section for the A boson and the branching fraction to Zh $\to$ $\ell\ell\tau\tau$. The observed upper limit at 95% confidence level ranges from 27 to 5 fb for A boson masses from 220 to 400 GeV, respectively. The results are used to constrain the extended Higgs sector parameters for two benchmark scenarios of the minimal supersymmetric standard model.