Search for ZH→ℓ+ℓ−bb-bar production in 9.7 fb(−1) of pp-bar collisions with the D0 detector

Abstract

We present a search for the standard model Higgs boson produced in association with a Z boson in 9.7 fb(−1) of pp-bar collisions collected with the D0 detector at the Fermilab Tevatron Collider at s√=1.96 TeV. Selected events contain one reconstructed Z→e(+)e(−) or Z→μ(+)μ(−) 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 standard model expectation. We set upper limits at the 95% C.L. on the product of the ZH production cross section and branching ratio B(H→bb-bar) 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 standard model prediction.