Search for the Production of the Standard Model Z Boson in Association with W Boson in P - Anti-p Collisions at 1.96 TeV Center of Mass Energy
Author | : |
Publisher | : |
Total Pages | : 162 |
Release | : 2010 |
ISBN-10 | : OCLC:727263082 |
ISBN-13 | : |
Rating | : 4/5 (82 Downloads) |
Book excerpt: The search for the production of the Standard Model Z boson in association with a W boson is motivated and discussed. This is performed using 4.3 fb−1 of Tevatron Run II data collected with the CDF detector in (square root)s = 1.96 TeV proton anti-proton collisions. This is a signature-based analysis where the W boson decays semileptonically into a high-P{sub T} electron or muon plus a neutrino, and where the Z boson decays into two b quark jets (b-jets). We increase the signal-to-background ratio by identifying the b-quarks in the jets with a new neural network-based algorithm. Another neural network then uses kinematic information to distinguish WZ to further increase the signal-to-background ratio. Since our sensitivity is still not enough to achieve an observation, we set a 95% Confidence Level upper limit on the product of the WZ production cross section and its branching fraction to the decay products specified above, and express it as a ratio to the theoretical Standard Model prediction. The resulting limit is 3.9 x SM (3.9 x SM expected).