Search for a pseudoscalar boson decaying into a Z boson and the 125 GeV Higgs boson in llbb final states

TL;DR

This paper reports a search for a pseudoscalar boson decaying into a Z boson and a 125 GeV Higgs boson using proton-proton collision data, setting upper limits on production without observing a signal.

Contribution

It introduces a search for a pseudoscalar A boson in the Zh decay channel using CMS data at 8 TeV, providing constraints within two Higgs doublet models.

Findings

No evidence for the A boson signal was found.

Upper limits were set on the production cross section times branching ratio.

Results constrain parameters of two Higgs doublet models.

Abstract

Results are reported on a search for decays of a pseudoscalar A boson into a Z boson and a light scalar h boson, where the Z boson decays into a pair of oppositely-charged electrons or muons, and the h boson decays into b anti-b. The search is based on data from proton-proton collisions at a center-of-mass energy sqrt(s)=8 TeV collected with the CMS detector, corresponding to an integrated luminosity of 19.7 inverse femtobarns. The h boson is assumed to be the standard model-like Higgs boson with a mass of 125 GeV. With no evidence for signal, upper limits are obtained on the product of the production cross section and the branching fraction of the A boson in the Zh channel. Results are also interpreted in the context of two Higgs doublet models.