77 research outputs found

    Present and Future CP Measurements

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    We review theoretical and experimental results on CP violation summarizing the discussions in the working group on CP violation at the UK phenomenology workshop 2000 in Durham.Comment: 104 pages, Latex, to appear in Journal of Physics

    Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

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    The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of s=1.96\sqrt s =1.96 TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is AFBttˉ=0.128±0.025A_{\mathrm{FB}}^{t\bar{t}} = 0.128 \pm 0.025. The combined inclusive and differential asymmetries are consistent with recent standard model predictions

    The Level-3 Trigger at the CDF Experiment at Tevatron Run II

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    We describe the filtering and analysis software running in the Collider Detector at Fermilab (CDF) Run II Level-3 trigger, as well as the client- and event-driven data hub system. These systems constitute critical components of the data acquisition system of the CDF detector. The Level-3 trigger is responsible for reconstructing the events and forming the final trigger decision. The consumer-server/logger (CSL) system receives the accepted physics events from multiple connections and writes them to disk in multiple streams, while distributing them to online analysis programs (consumers). Since 2001, the system has been running successfully at high throughput rates: the Level-3 trigger reduces the event rate from 350 Hz to about 100 Hz with an average event size of 150 kB, while the CSL is able to process up to 22 MB/s of constant event logging. We describe these systems in detail and report on their current performance. We briefly outline upgrade plans for the remainder of Tevatron Run II. © 2005 IEEE.F.I. 1,7370info:eu-repo/semantics/publishe

    High-precision measurement of the W boson mass with the CDF II detector

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    The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass, MW, using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 tera–electron volt center-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. A sample of approximately 4 million W boson candidates is used to obtain MW=80,433.5±6.4stat±6.9syst=80,433.5±9.4 MeV/c2, the precision of which exceeds that of all previous measurements combined (stat, statistical uncertainty; syst, systematic uncertainty; MeV, mega–electron volts; c, speed of light in a vacuum). This measurement is in significant tension with the standard model expectation.ISSN:0036-8075ISSN:1095-920
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