Professor Daniela Bortoletto

Abstract:

We present a measurement of the cross section for W-boson production in association with jets in pp̄ collisions at s=1.96TeV. The analysis uses a data sample corresponding to an integrated luminosity of 320pb-1 collected with the CDF II detector. W bosons are identified in their electron decay channel and jets are reconstructed using a cone algorithm. For each W+≥n-jet sample (n=1-4) we measure the differential cross section dσ(pp̄→W+≥ n-jet)/dETnth-jet×B(W→eν) with respect to the transverse energy ET of the nth-highest ET jet above 20GeV, and the total cross section σ(pp̄→W+≥n-jet;ETnth-jet>25GeV)×B(W→eν), for a restricted W→eν decay phase space. The cross sections, corrected for all detector effects, can be directly compared to particle level W+jet(s) predictions. We present here comparisons to leading order and next-to-leading order predictions. © 2008 The American Physical Society.

Abstract:

We report on the results of a search for standard model Higgs bosons produced in association with W bosons from pp̄ collisions at s=1.96TeV. The search uses a data sample corresponding to approximately 1fb-1 of integrated luminosity. Events consistent with the W→ ν and H→bb̄ signature are selected by triggering on a high-pT electron or muon candidate and tagging one or two of the jet candidates as having originated from b quarks. A neural network filter rejects a fraction of tagged charm and light-flavor jets, increasing the b-jet purity in the sample. We observe no excess νbb̄ production beyond the background expectation, and we set 95% confidence level upper limits on the production cross section times branching fraction σ(pp̄→WH)Br(H→bb̄) ranging from 3.9 to 1.3 pb, for specific Higgs boson mass hypotheses in the range 110 to 150GeV/c2, respectively. © 2008 The American Physical Society.