9,269 research outputs found

    Measurement of CP Violation at the Υ(4S)\Upsilon(4S) without Time Ordering or Δt\Delta t

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    I derive the expressions for the CP-violating asymmetry arising from interference between mixed and direct decays in the Upsilon(4S) system, for the case in which only one of the B decay times is observed, integrating over the decay time of the other B. I observe that neither the difference of the decay times Delta t, nor even their time-ordering, need be detected. A technique for measurement of the CP-violating weak decay parameter sin(2beta) is described which exploits this observation.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    Operator Product Expansion for Exclusive Decays: B^+ ->Ds^+ e+e- and B^+ -> Ds^{*+} e+e-

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    The decays B+Ds,d+e+eB^+\to D_{s,d}^+e^+e^- and B+Ds,d+e+eB^+\to D_{s,d}^{*+}e^+e^- proceed through a weak and an electromagnetic interaction. This is a typical ``long distance'' process, usually difficult to compute systematically. We propose that over a large fraction of phase space a combination of an operator product and heavy quark expansions effectively turns this process into one in which the weak and electromagnetic interactions occur through a local operator. Moreover, we use heavy quark spin symmetry to relate all the local operators that appear in leading order of the operator expansion to two basic ones. We use this operator expansion to estimate the decay rates for B+Ds,d()+e+eB^+\to D_{s,d}^{(*)+}e^+e^-.Comment: 4 pages, 1 figure, Latex, published version in PR

    The Semileptonic Decays Dπ(ρ)eνD\to \pi(\rho) e \nu and Bπ(ρ)eνB\to \pi (\rho) e \nu from QCD Sum Rules

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    We investigate the semileptonic decays of B and D mesons into π\pi and ρ\rho mesons, respectively, by means of QCD sum rules. We find that for the vector formfactors involved the pole dominance hypothesis is valid to good accuracy with pole masses in the expected range. Pole dominance, however, does not apply to the axial formfactors which results in specific predictions for the predominant polarization of the ρ\rho meson and the shape of the lepton spectrum. For the total decay rates we find Γ(Bˉ0π+eνˉ)=(5.1±1.1)Vub21012s1\Gamma (\bar B^0 \to \pi^+ e^- \bar\nu) = (5.1\pm 1.1)\,|V_{ub}|^2\, 10^{12}\,{\rm s^{-1}}, Γ(D0πe+ν)=(8.0±1.7)Vcd21010s1\Gamma ( D^0 \to \pi^- e^+ \nu) = (8.0\pm 1.7)\,|V_{cd}|^2\, 10^{10}\,{\rm s^{-1}}, Γ(Bˉ0ρ+eνˉ)=(1.2±0.4)Vub21013s1\Gamma (\bar B^0 \to \rho^+ e^- \bar\nu) = (1.2\pm 0.4\,)\,|V_{ub}|^2\, 10^{13}\,{\rm s^{-1}} and Γ(D0ρe+ν)=(2.4±0.7)Vcd2109s1\Gamma (D^0 \to \rho^- e^+\nu) = (2.4\pm 0.7)\,|V_{cd}|^2\, 10^{9}\,{\rm s^{-1}}.Comment: 23 pages, 12 figures included as uu-encoded file, needs REVTEX, TUM--T31--39/9

    Determination of the Jet Energy Scale at the Collider Detector at Fermilab

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    A precise determination of the energy scale of jets at the Collider Detector at Fermilab at the Tevatron ppˉp\bar{p} collider is described. Jets are used in many analyses to estimate the energies of partons resulting from the underlying physics process. Several correction factors are developed to estimate the original parton energy from the observed jet energy in the calorimeter. The jet energy response is compared between data and Monte Carlo simulation for various physics processes, and systematic uncertainties on the jet energy scale are determined. For jets with transverse momenta above 50 GeV the jet energy scale is determined with a 3% systematic uncertainty
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