143 research outputs found

    B Lambda_b and Charm Results from the Tevatron

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    Recent results on BdB_d, Bu±B_u^{\pm}, BsB_s, Λb\Lambda_b and Charm hadrons are reported from \approx 75pb1^{-1} and \approx 40 pb1^{-1} of data accumulated at the upgraded CDF and D0 experiments at the Fermilab Tevatron pˉp\bar{p}-p collider, during Run-II. These include lifetime and mass measurements of BB and Charm hadrons, searches for rare decays in charm and BB hadrons and CP-violation in Charm decays. Results relevant to CP-violation in B-decays are also reported.Comment: 10 pages, 8 figures (+ 1 photo) Physics in Collision 2003 PNC FRAT0

    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

    Deep Underground Neutrino Experiment (DUNE) near detector conceptual design report

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    The Deep Underground Neutrino Experiment (DUNE) is an international, world-class experiment aimed at exploring fundamental questions about the universe that are at the forefront of astrophysics and particle physics research. DUNE will study questions pertaining to the preponderance of matter over antimatter in the early universe, the dynamics of supernovae, the subtleties of neutrino interaction physics, and a number of beyond the Standard Model topics accessible in a powerful neutrino beam. A critical component of the DUNE physics program involves the study of changes in a powerful beam of neutrinos, i.e., neutrino oscillations, as the neutrinos propagate a long distance. The experiment consists of a near detector, sited close to the source of the beam, and a far detector, sited along the beam at a large distance. This document, the DUNE Near Detector Conceptual Design Report (CDR), describes the design of the DUNE near detector and the science program that drives the design and technology choices. The goals and requirements underlying the design, along with projected performance are given. It serves as a starting point for a more detailed design that will be described in future documents

    Lectures in relativistic quantum mechanics: an introductory course for postgraduates in particle physics

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    This book is based on a series of lectures taught by the author to all incoming first year Oxford University postgraduates in experimental particle physics. It begins by deriving the Dirac equation and incorporating the electro-magnetic interaction and calculating several bread and butter processes at tree level using the Feynman Stueckelberg approach: Mott scattering, electron-electron scattering, electron-positron scattering, Compton scattering, Bremsstrahlung and electron-positron to muon-anti-muon. The intention is for the student to become fluent in detail with all the steps leading to the calculation of these processes. Every step is motivated using the most basic arguments

    Measurement of the lifetime of the B(s)0 meson using the exclusive decay mode B(s)0 ---> J / psi phi

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    Measurement of the CP violating phase [beta]s in B_s^0 [rightarrow] J/[psi][phi] decays

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    The CP violating phase βJ/ψφs is measured in decays of B0s → J/ψφ. This measurement uses 5.2 fb-1 of data collected in √—s = 1.96 TeV p̅p collisions at the Fermilab Tevatron with the CDF Run-II detector. CP violation in the B0s-̅B0sbar system is predicted to be very small in the Standard Model. However, several theories beyond the Standard Model allow enhancements to this quantity by heavier, New Physics particles entering second order weak mixing box diagrams. Previous measurements have hinted at a deviation from the Standard Model expectation value for βJ/ψφs with a significance of approximately 2σ. The measurement described in this thesis uses the highest statistics sample available to date in the B0s rightarrow; J/ψφ decay channel, where J/ψ → μ+ μ− and φ → K+K−. Furthermore, it contains several improvements over previous analyses, such as enhanced signal selection, fully calibrated particle ID and flavour tagging, and the inclusion of an additional decay component in the likelihood function. The added decay component considers S-wave states of KK pairs in the B0s → J/ψK+K− channel. The results are presented as 2-dimensional frequentist confidence regions for βJ/ψφs and ΔΓ (the width difference between the B0s mass eigenstates), and as a confidence interval for βJ/ψφs of [0.02,0.52] U [1.08, 1.55] at the 68 % confidence level. The measurement of the CP violating phase obtained in this thesis is complemented by the world's most precise measurement of the lifetime τs = 1.53 ± 0.025 (stat.) ± 0.012 (syst.) ps and decay width difference ΔΓ = 0.075 ± 0 .035 (stat.) ± 0.01 (syst.) ps−1 of the B0s meson, with the assumption of no CP violation.This thesis is not currently available in OR

    Measurement of using pairs from bosons produced in collisions at a center-of-momentum energy of 1.96 TeV

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    At the Fermilab Tevatron proton-antiproton (ppˉp\bar{p}) collider, Drell-Yan lepton pairs are produced in the process ppˉe+e+Xp \bar{p} \rightarrow e^+e^- + X through an intermediate γ/Z\gamma^*/Z boson. The forward-backward asymmetry in the polar-angle distribution of the ee^- as a function of the e+ee^+e^--pair mass is used to obtain sin2θefflept\sin^2\theta^{\rm lept}_{\rm eff}, the effective leptonic determination of the electroweak-mixing parameter sin2θW\sin^2\theta_W. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.4~fb1^{-1} of integrated luminosity from ppˉp\bar{p} collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of sin2θefflept\sin^2\theta^{\rm lept}_{\rm eff} is found to be 0.23248±0.000530.23248 \pm 0.00053. The combination with the previous CDF measurement based on μ+μ\mu^+\mu^- pairs yields sin2θefflept=0.23221±0.00046\sin^2\theta^{\rm lept}_{\rm eff} = 0.23221 \pm 0.00046. This result, when interpreted within the specified context of the standard model assuming sin2θW=1MW2/MZ2\sin^2 \theta_W = 1 - M_W^2/M_Z^2 and that the WW- and ZZ-boson masses are on-shell, yields sin2θW=0.22400±0.00045\sin^2\theta_W = 0.22400 \pm 0.00045, or equivalently a WW-boson mass of 80.328±0.024  GeV/c280.328 \pm 0.024 \;{\rm GeV}/c^2

    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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