Sarah Lockwitz

This dissertation presents a search for the standard model Higgs boson in the associated production process proton anti-proton to ZH to electron positron b quark anti-b quark. Data amounting to an integrated luminosity of 7.5/fb at a center of mass energy of 1.96 TeV collected at the Collider Detector at Fermilab (CDF) at the Tevatron are analyzed. Two objectives are pursued in the methods applied: maximize acceptance, and distinguish the signal from background. The first aim is met by applying a neural-network-based electron identification and considering multiple electron triggers in an effort to improve Z boson acceptance. In an attempt to maximize the Higgs acceptance, three b quark identification schemes are used allowing for varying event conditions. The latter goal is met by employing more multivariate techniques. First, the dijet mass resolution is improved by a neural network. Then, both single variables and boosted decision tree outputs are fed into a segmented final discriminant simultaneously isolating the signal-like events from the Z with additional jets background and the kinematically different top anti-top background. Good agreement is seen with the null hypothesis and upper production cross section times branching ratio (BR(H to b anti b)) limits are set for 11 mass hypotheses between 100 and 150 GeV/c^2 at the 95% confidence level. For a Higgs boson mass of 115 GeV/c^2, this channel sets an observed (expected) upper limit of 3.9 (5.8) times the standard model value of production cross section times branching ratio. The inclusion of this channel within the combined CDF and Tevatron limits is discussed.