4 research outputs found

    Search for Anomalous Production of Events with Two Photons and Additional Energetic Objects at CDF

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    submitted to Phys. Rev. DInternational audienceWe present results of a search for anomalous production of two photons together with an electron, muon, τ\tau lepton, missing transverse energy, or jets using ppˉp\bar{p} collision data from 1.1-2.0 fb1^{-1} of integrated luminosity collected by the Collider Detector at Fermilab (CDF). The event yields and kinematic distributions are examined for signs of new physics without favoring a specific model of new physics. The results are consistent with the standard model expectations. The search employs several new analysis techniques that significantly reduce instrumental backgrounds in channels with an electron and missing transverse energy

    Search for Technicolor Particles Produced in Association with a W Boson at CDF

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    submitted to Phys. Rev. LettInternational audienceWe present a search for the technicolor particles ρT\rho_{T} and πT\pi_{T} in the process ppˉρTWπTp\bar{p} \to \rho_{T} \to W\pi_{T} at a center of mass energy of s=1.96TeV\sqrt{s}=1.96 \mathrm{TeV}. The search uses a data sample corresponding to approximately 1.9fb11.9 \mathrm{fb}^{-1} of integrated luminosity accumulated by the CDF II detector at the Fermilab Tevatron. The event signature we consider is WνW\to \ell\nu and πTbbˉ,bcˉ\pi_{T} \to b\bar{b}, b\bar{c} or buˉb\bar{u} depending on the πT\pi_{T} charge. We select events with a single high-pTp_T electron or muon, large missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with multiple bb-tagging algorithms. The observed number of events and the invariant mass distributions are consistent with the standard model background expectations, and we exclude a region at 95% confidence level in the ρT\rho_T-πT\pi_T mass plane. As a result, a large fraction of the region m(ρT)=180m(\rho_T) = 180 - 250GeV/c2250 \mathrm{GeV}/c^2 and m(πT)=95m(\pi_T) = 95 - 145GeV/c2145 \mathrm{GeV}/c^2 is excluded

    Measurement of Z gamma Production in pbar{p} Collisions at sqrt{s} = 1.96 TeV

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    8 pages, 3 figures, Submitted to PRDThe production rate and kinematics of photons produced in association with Z bosons are studied using 2/fb of p\bar{p} collision data collected at the Collider Detector at Fermilab. The cross section for p\bar{p} -> l^+ l^- gamma + X (where the leptons l are either muons or electrons with dilepton mass M_{ll} > 40 GeV/c^2, and where the photon has transverse energy Et_{gamma} > 7 GeV and is well separated from the leptons) is 4.6 +/- 0.2 (stat) +/- 0.3 (syst) +/- 0.3 (lum) pb, which is consistent with standard model expectations. We use the photon Et distribution from Z-gamma events where the Z has decayed to mu^+ mu^-, e^+ e^-, or nu\bar{nu} to set limits on anomalous (non-standard-model) trilinear couplings between photons and Z bosons

    Organelle Biosynthesis: The Chloroplast

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