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Top Quark Physics at the CDF Experiment

Description: Fermilab's Tevatron accelerator is recently performing at record luminosities that enables a program systematically addressing the physics of top quarks. The CDF collaboration has analyzed up to 5 fb{sup -1} of proton anti-proton collisions from the Tevatron at a center of mass energy of 1.96 TeV. The large datasets available allow to push top quark measurements to higher and higher precision and have lead to the recent observation of electroweak single top quark production at the Tevatron. This article reviews recent results on top quark physics from the CDF experiment.
Date: July 1, 2010
Creator: Stelzer, Bernd & Collaboration, for the CDF
Partner: UNT Libraries Government Documents Department

Exotic Photon Searches at CDF II

Description: We present recent results of searches for exotic photons at CDF II. In the first signature-based search, we search for anomalous production of two photons with additional energetic objects. The results are consistent with the standard model expectations. In the second analysis, we present a signature-based search for anomalous production of events containing a photon, two jets, of which at least one is identified as originating from a b quark, and missing transverse energy. We find no indications of non-standard model phenomena. Finally, a search for a fermiophobic Higgs in the diphoton final state is presented. Since no evidence of a resonance in the diphoton mass spectrum is observed we exclude this Higgs boson with mass below 106 GeV/c{sup 2} at a 95% confidence level.
Date: October 1, 2009
Creator: Lee, Eunsin & collaboration, for the CDF
Partner: UNT Libraries Government Documents Department

Properties of Weakly-decaying Bottom Baryons, Xi_b^- and Omega_b^-, at CDF

Description: We present properties of weakly decaying bottom baryons, {Xi}{sub b}{sup -} and {Omega}{sub b}{sup -}, using 4.2 fb{sup -1} of data from p{bar p} collisions at {radical}s = 1.96 TeVf, and recorded with the Collider Detector at Fermilab. They report the observation of the {Omega}{sub b}{sup -} through the decay chain {Omega}{sub b}{sup -} {yields} J/{psi}{omega}{sup -}, where J/{psi} {yields} {mu}{sup +}{mu}{sup -}, {Omega}{sup -} {yields} {Lambda}K{sup -}, and {Lambda} {yields} p{pi}{sup -}. Significance of the observed signal is estimated to be 5.5 Gaussian standard deviations. The {Omega}{sub b}{sup -} mass and lifetime are measured to be 6054.4 {+-} 6.8(stat.) {+-} 0.9(syst.) MeV/c{sup 2} and 1.13{sub -0.40}{sup +0.53}(stat.) {+-} 0.02(syst). ps, respectively. In addition, the mass and lifetime of the {Xi}{sub b}{sup -} baryon are measured to be 5790.9 {+-} 2.6(stat.) {+-} 0.8(syst.) MeV/c{sup 2} and 1.56{sub -0.25}{sup +0.27}(stat.) {+-} 0.02(syst.) ps, respectively. Under the assumption that the {Xi}{sub b}{sup -} and {Omega}{sub b}{sup -} are produced with similar kinematic distributions as the {Lambda}{sub b}{sup 0} baryon, we measure {sigma}({Xi}{sub b}{sup -}){Beta}({Xi}{sub b}{sup -}) {yields} J/{psi}({Xi}{sup -})/{sigma}({Lambda}{sub b}{sup 0}){Beta}({Lambda}{sub b}{sup 0} {yields} J/{psi} {Lambda}) = 0.167{sub -0.025}{sup +0.037}(stat.) {+-} 0.012(syst.) and {sigma}({omega}{sub b}{sup -}){Beta}({Omega}{sub b}{sup -} J/{psi} {Omega}{sup -})/{sigma}({Lambda}{sub b}{sup 0}){Beta}({Lambda}{sub b}{sup 0}) {yields} J/{psi} {Lambda} = 0.045{sub 0.012}{sup +0.017}(stat.) {+-} 0.004(syst.) for baryons produced with transverse momentum in the range of 6-20 GeV/c.
Date: October 1, 2009
Creator: Behari, Satyajit & Collaboration, for the CDF
Partner: UNT Libraries Government Documents Department

Diffractive and Exclusive Production at the Tevatron

Description: Exclusive Higgs production, in which the event consists of nothing but the leading protons and a Higgs boson, has been proposed as a channel in which to study the properties of the Higgs boson at the Large Hadron Collider (LHC). Although we do not expect to observe exclusive Higgs-boson production at the Tevatron, we can observe similar processes which provide a calibration for theoretical predictions of exclusive Higgs production at the LHC. The CDF measurements of exclusive dijet and diphoton production, examples of such processes, are presented in Sec. 2. Single diffraction has been studied extensively at the Tevatron in Run I, including diffractive dijet and W/Z-boson production. New results with extended kinematical reach allowed by the larger Run II dataset are presented in Sec. 3. CDF II includes forward detectors designed for studying diffractive physics. The MiniPlug calorimeters cover the pseudorapidity region 3.5<|{eta}|<5.1. Beam Shower Counters (BSC) surrounding the beampipe in several locations detect particles in the forward region 5.4<|{eta}|<7.4. A spectrometer consisting of three Roman-pot detectors preceded by Tevatron dipoles is used to track diffractive antiprotons which have lost a fraction 0.03<{zeta}<0.10 of the beam momentum.
Date: October 1, 2008
Creator: Convery, M.E. & Collaboration, for the CDF
Partner: UNT Libraries Government Documents Department

Charmless and Penguin Decays at CDF

Description: Penguin transitions play a key role in the search of New Physics hints in the heavy flavor sector. During the last decade CDF has been exploring this opportunity with a rich study of two-body charmless decays of neutral B mesons into charged final-state particles. After briefly introducing the aspects of this physics peculiar to the hadron collision environment, I report on two interesting results: the first polarization measurement of the B{sub s}{sup 0} {yields} {phi}{phi} decay and the update of the B{sub (s)}{sup 0} {yields} h{sup +}h{prime}{sup -} decays analysis.
Date: December 1, 2010
Creator: Dorigo, Mirco & Collaboration, for the CDF
Partner: UNT Libraries Government Documents Department

Combination of CDF and D0 Measurements of the Single Top Production Cross Section

Description: We report a combination of the CDF and D0 measurements of the inclusive single top quark production cross section in the s- and t-channels, {sigma}{sub s+t}, in p{bar p} collisions at a center of mass energy of 1.96 TeV. The total integrated luminosity included in CDF's analysis is 3.2 fb{sup -1} and D0's analysis has 2.3 fb{sup -1}. A Bayesian analysis is used to extract the cross section from the distributions of multivariate discriminants provided by the collaborations. For a top quark mass m{sub t} = 170 GeV/c{sup 2}, we measure a cross section of 2.76{sub -0.47}{sup +0.58} pb. We extract the CKM matrix element |V{sub tb}| = 0.88 {+-} 0.07 with a 95% C.L. lower limit of |V{sub tb}| > 0.77.
Date: August 1, 2009
Creator: Group, Tevatron Electroweak Working; Collaboration, for the CDF & Collaboration, the D0
Partner: UNT Libraries Government Documents Department