A combined search for the standard model Higgs boson at s=1.96 TeV

We present new results of the search for WH→ℓνbb¯ production in pp¯ collisions at a center-of-mass energy of s=1.96 TeV, based on a dataset with integrated luminosity of 0.44 fb−10.44 fb−1. We combine these new results with previously published searches by the D0 collaboration, for WH and ZH   production analyzed in the E̸Tbb¯ final state, for ZH   (→ℓ+ℓ−bb¯) production, for WH   (→WWW→WWW) production, and for H   (→WW→WW) direct production. No signal-like excess is observed either in the WH   analysis or in the combination of all D0 Higgs boson analyses. We set 95% C.L. (expected) upper limits on σ(pp¯→WH)×B(H→bb¯) ranging from 1.6 (2.2) pb to 1.9 (3.3) pb for Higgs boson masses between 105 and 145 GeV, to be compared to the theoretical prediction of 0.13 pb for a Standard Model (SM) Higgs boson with mass mH=115 GeVmH=115 GeV. After combination with the other D0 Higgs boson searches, we obtain for mH=115 GeVmH=115 GeV an observed (expected) limit 8.5 (12.1) times higher than the SM predicted Higgs boson production cross section. For mH=160 GeVmH=160 GeV, the corresponding observed (expected) ratio is 10.2 (9.0).