Search for the standard model Higgs boson produced in association with a $W^{\pm}$ boson with 7.5 fb$^{-1}$ integrated luminosity at CDF

Abstract

We present a search for the standard model Higgs boson produced in association with a $W^{\pm}$ boson. This search uses data corresponding to an integrated luminosity of 7.5 fb$^{-1}$ collected by the CDF detector at the Tevatron. We select $WH \to \ellνb \bar{b}$ candidate events with two jets, large missing transverse energy, and exactly one charged lepton. We further require that at least one jet be identified to originate from a bottom quark. Discrimination between the signal and the large background is achieved through the use of a Bayesian artificial neural network. The number of tagged events and their distributions are consistent with the standard model expectations. We observe no evidence for a Higgs boson signal and set 95% C.L. upper limits on the $WH$ production cross section times the branching ratio to decay to $b\bar b$ pairs, $σ(p\bar p \rightarrow W^{\pm} H) \times {\cal B}(H\rightarrow b\bar b)$, relative to the rate predicted by the standard model. For the Higgs boson mass range of 100 GeV/c$^2$ to 150 GeV/c$^2$ we set observed (expected) upper limits from 1.34 (1.83) to 38.8 (23.4). For 115 GeV/c$^2$ the upper limit is 3.64 (2.78). The combination of the present search with an independent analysis that selects events with three jets yields more stringent limits ranging from 1.12 (1.79) to 34.4 (21.6) in the same mass range. For 115 GeV/c$^2$ the upper limit is 2.65 (2.60).