Search for ZH -> l+l- bbar production in 9.7 fb-1 of ppbar collisions with the D0 detector

TL;DR

This paper reports a search for the associated production of the Higgs boson with a Z boson in proton-antiproton collisions, setting upper limits on the production rate for Higgs masses between 90 and 150 GeV.

Contribution

First search for ZH production in ppbar collisions at Fermilab, with new upper limits on Higgs production cross section times branching ratio.

Findings

Measured ZZ production cross section consistent with SM.

Set upper limits on ZH production for Higgs masses 90-150 GeV.

Observed limit at 125 GeV is 7.1 times the SM prediction.

Abstract

We present a search for the standard model (SM) Higgs boson produced in association with a Z boson in 9.7 fb-1 of ppbar collisions collected with the D0 detector at the Fermilab Tevatron Collider at sqrt{s} = 1.96 TeV. Selected events contain one reconstructed Z -> e+e- or Z -> mu+mu- candidate and at least two jets, including at least one jet likely to contain a b quark. To validate the search procedure, we also measure the cross section for ZZ production, and find that it is consistent with the SM expectation. We set upper limits at the 95% C.L. on the product of the ZH production cross section and branching ratio B(H -> bbbar) for Higgs boson masses 90 <= M_H <= 150 GeV. The observed (expected) limit for M_H = 125 GeV is a factor of 7.1 (5.1) larger than the SM prediction.