661 research outputs found

    POOL File Catalog, Collection and Metadata Components

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    The POOL project is the common persistency framework for the LHC experiments to store petabytes of experiment data and metadata in a distributed and grid enabled way. POOL is a hybrid event store consisting of a data streaming layer and a relational layer. This paper describes the design of file catalog, collection and metadata components which are not part of the data streaming layer of POOL and outlines how POOL aims to provide transparent and efficient data access for a wide range of environments and use cases - ranging from a large production site down to a single disconnected laptops. The file catalog is the central POOL component translating logical data references to physical data files in a grid environment. POOL collections with their associated metadata provide an abstract way of accessing experiment data via their logical grouping into sets of related data objects.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 4 pages, 1 eps figure, PSN MOKT00

    Evidence for the Rare Decay B -> K*ll and Measurement of the B -> Kll Branching Fraction

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    We present evidence for the flavor-changing neutral current decay BK+B\to K^*\ell^+\ell^- and a measurement of the branching fraction for the related process BK+B\to K\ell^+\ell^-, where +\ell^+\ell^- is either an e+ee^+e^- or μ+μ\mu^+\mu^- pair. These decays are highly suppressed in the Standard Model, and they are sensitive to contributions from new particles in the intermediate state. The data sample comprises 123×106123\times 10^6 Υ(4S)BBˉ\Upsilon(4S)\to B\bar{B} decays collected with the Babar detector at the PEP-II e+ee^+e^- storage ring. Averaging over K()K^{(*)} isospin and lepton flavor, we obtain the branching fractions B(BK+)=(0.650.13+0.14±0.04)×106{\mathcal B}(B\to K\ell^+\ell^-)=(0.65^{+0.14}_{-0.13}\pm 0.04)\times 10^{-6} and B(BK+)=(0.880.29+0.33±0.10)×106{\mathcal B}(B\to K^*\ell^+\ell^-)=(0.88^{+0.33}_{-0.29}\pm 0.10)\times 10^{-6}, where the uncertainties are statistical and systematic, respectively. The significance of the BK+B\to K\ell^+\ell^- signal is over 8σ8\sigma, while for BK+B\to K^*\ell^+\ell^- it is 3.3σ3.3\sigma.Comment: 7 pages, 2 postscript figues, submitted to Phys. Rev. Let

    A Study of Time-Dependent CP Asymmetry in B 0 → J/ψ π 0 Decays The BABAR Collaboration

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    We present our first study of the time-dependent CP-violating asymmetry in B 0 → J/ψ π 0 decays using e + e − annihilation data collected with the BABAR detector at the Υ (4S) resonance during the years 1999–2002 at the PEP-II asymmetric-energy B Factory at SLAC. With about 88 million BB pairs, our preliminary results for the coefficients of the cosine and sine terms of the CP asymmetr

    Measurement of the Branching Fraction for B- --> D0 K*-

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    We present a measurement of the branching fraction for the decay B- --> D0 K*- using a sample of approximately 86 million BBbar pairs collected by the BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the K*- through its decay to K0S pi-. We measure the branching fraction to be B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid Communications

    The Physics of the B Factories

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    This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C

    Measurement of the branching fraction for BD0KB^- \to D^0 K^{*-}

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    We present a measurement of the branching fraction for the decay B- --> D0 K*- using a sample of approximately 86 million BBbar pairs collected by the BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the K*- through its decay to K0S pi-. We measure the branching fraction to be B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}

    CMS physics technical design report : Addendum on high density QCD with heavy ions

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    Observation of a significant excess of π0π0\pi^{0}\pi^{0} events in B meson decays

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    We present an observation of the decay B0π0π0B^{0} \to \pi^{0} \pi^{0} based on a sample of 124 million BBˉB\bar{B} pairs recorded by the BABAR detector at the PEP-II asymmetric-energy BB Factory at SLAC. We observe 46±13±346 \pm 13 \pm 3 events, where the first error is statistical and the second is systematic, corresponding to a significance of 4.2 standard deviations including systematic uncertainties. We measure the branching fraction \BR(B^{0} \to \pi^{0} \pi^{0}) = (2.1 \pm 0.6 \pm 0.3) \times 10^{-6}, averaged over B0B^{0} and Bˉ0\bar{B}^{0} decays

    Measurement of the CP-Violating Asymmetry Amplitude sin2β\beta

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    We present results on time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 88 million Y(4S) --> B Bbar decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We study events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B0 or B0bar from its decay products. The amplitude of the CP-violating asymmetry, which in the Standard Model is proportional to sin2beta, is derived from the decay-time distributions in such events. We measure sin2beta = 0.741 +/- 0.067 (stat) +/- 0.033 (syst) and |lambda| = 0.948 +/- 0.051 (stat) +/- 0.017 (syst). The magnitude of lambda is consistent with unity, in agreement with the Standard Model expectation of no direct CP violation in these modes
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