497 research outputs found

    Helicity conservation in inclusive nonleptonic decay B to VX: Test of long-distance final state interaction

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    The polarization measurement in the inclusive B decay provides us with a simple test of how much the long-distance final-state interaction takes place as the energy of the observed meson varies in the final state. We give the expectation of the perturbative QCD for the energy dependence of the helicity fractions in a semiquantitative form. Experiment will tell us for which decay processes the perturbative calculation should be applicable.Comment: 15 pages in Revtex with 3 figures embedde

    Updated Analysis of a_1 and a_2 in Hadronic Two-body Decays of B Mesons

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    Using the recent experimental data of BD()(π,ρ)B\to D^{(*)}(\pi,\rho), BD()Ds()B\to D^{(*)} D_s^{(*)}, BJ/ψK()B\to J/\psi K^{(*)} and various model calculations on form factors, we re-analyze the effective coefficients a_1 and a_2 and their ratio. QCD and electroweak penguin corrections to a_1 from BD()Ds()B\to D^{(*)}D_s^{(*)} and a_2 from BJ/ψK()B\to J/\psi K^{(*)} are estimated. In addition to the model-dependent determination, the effective coefficient a_1 is also extracted in a model-independent way as the decay modes BD()hB\to D^{(*)}h are related by factorization to the measured semileptonic distribution of BD()νˉB\to D^{(*)}\ell \bar\nu at q2=mh2q^2=m_h^2. Moreover, this enables us to extract model-independent heavy-to-heavy form factors, for example, F0BD(mπ2)=0.66±0.06±0.05F_0^{BD}(m_\pi^2)=0.66\pm0.06\pm0.05 and A0BD(mπ2)=0.56±0.03±0.04A_0^{BD^*}(m_\pi^2)=0.56\pm0.03\pm0.04. The determination of the magnitude of a_2 from BJ/ψK()B\to J/\psi K^{(*)} depends on the form factors F1BKF_1^{BK}, A1,2BKA_{1,2}^{BK^*} and VBKV^{BK^*} at q2=mJ/ψ2q^2=m^2_{J/\psi}. By requiring that a_2 be process insensitive (i.e., the value of a_2 extracted from J/ψKJ/\psi K and J/ψKJ/\psi K^* states should be similar), as implied by the factorization hypothesis, we find that BK()B\to K^{(*)} form factors are severely constrained; they respect the relation F1BK(mJ/ψ2)1.9A1BK(mJ/ψ2)F_1^{BK}(m^2_{J/\psi})\approx 1.9 A_1^{BK^*}(m^2_{J/\psi}). Form factors A2BKA_2^{BK^*} and VBKV^{BK^*} at q2=mJ/ψ2q^2=m^2_{J/\psi} inferred from the measurements of the longitudinal polarization fraction and the P-wave component in BJ/ψKB\to J/\psi K^* are obtained. A stringent upper limit on a_2 is derived from the current bound on \ov B^0\to D^0\pi^0 and it is sensitive to final-state interactions.Comment: 33 pages, 2 figures. Typos in Tables I and IX are corrected. To appear in Phys. Rev.

    Final-State Phases in Charmed Meson Two-Body Nonleptonic Decays

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    Observed decay rates indicate large phase differences among the amplitudes for the charge states in DKˉπD \to \bar K \pi and DKˉπD \to \bar K^* \pi but relatively real amplitudes in the charge states for DKˉρD \to \bar K \rho. This feature is traced using an SU(3) flavor analysis to a sign flip in the contribution of one of the amplitudes contributing to the latter processes in comparison with its contribution to the other two sets. This amplitude may be regarded as an effect of rescattering and is found to be of magnitude comparable to others contributing to charmed particle two-body nonleptonic decays.Comment: 19 pages, latex, 4 figures, to be submitted to Phys. Rev.

    Study of the B^0 Semileptonic Decay Spectrum at the Upsilon(4S) Resonance

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    We have made a first measurement of the lepton momentum spectrum in a sample of events enriched in neutral B's through a partial reconstruction of B0 --> D*- l+ nu. This spectrum, measured with 2.38 fb**-1 of data collected at the Upsilon(4S) resonance by the CLEO II detector, is compared directly to the inclusive lepton spectrum from all Upsilon(4S) events in the same data set. These two spectra are consistent with having the same shape above 1.5 GeV/c. From the two spectra and two other CLEO measurements, we obtain the B0 and B+ semileptonic branching fractions, b0 and b+, their ratio, and the production ratio f+-/f00 of B+ and B0 pairs at the Upsilon(4S). We report b+/b0=0.950 (+0.117-0.080) +- 0.091, b0 = (10.78 +- 0.60 +- 0.69)%, and b+ = (10.25 +- 0.57 +- 0.65)%. b+/b0 is equivalent to the ratio of charged to neutral B lifetimes, tau+/tau0.Comment: 14 page, postscript file also available at http://w4.lns.cornell.edu/public/CLN

    Time-integrated luminosity recorded by the BABAR detector at the PEP-II e+e- collider

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    This article is the Preprint version of the final published artcile which can be accessed at the link below.We describe a measurement of the time-integrated luminosity of the data collected by the BABAR experiment at the PEP-II asymmetric-energy e+e- collider at the ϒ(4S), ϒ(3S), and ϒ(2S) resonances and in a continuum region below each resonance. We measure the time-integrated luminosity by counting e+e-→e+e- and (for the ϒ(4S) only) e+e-→μ+μ- candidate events, allowing additional photons in the final state. We use data-corrected simulation to determine the cross-sections and reconstruction efficiencies for these processes, as well as the major backgrounds. Due to the large cross-sections of e+e-→e+e- and e+e-→μ+μ-, the statistical uncertainties of the measurement are substantially smaller than the systematic uncertainties. The dominant systematic uncertainties are due to observed differences between data and simulation, as well as uncertainties on the cross-sections. For data collected on the ϒ(3S) and ϒ(2S) resonances, an additional uncertainty arises due to ϒ→e+e-X background. For data collected off the ϒ resonances, we estimate an additional uncertainty due to time dependent efficiency variations, which can affect the short off-resonance runs. The relative uncertainties on the luminosities of the on-resonance (off-resonance) samples are 0.43% (0.43%) for the ϒ(4S), 0.58% (0.72%) for the ϒ(3S), and 0.68% (0.88%) for the ϒ(2S).This work is supported by the US Department of Energy and National Science Foundation, the Natural Sciences and Engineering Research Council (Canada), the Commissariat à l’Energie Atomique and Institut National de Physique Nucléaire et de Physiquedes Particules (France), the Bundesministerium für Bildung und Forschung and Deutsche Forschungsgemeinschaft (Germany), the Istituto Nazionale di Fisica Nucleare (Italy), the Foundation for Fundamental Research on Matter (The Netherlands), the Research Council of Norway, the Ministry of Education and Science of the Russian Federation, Ministerio de Ciencia e Innovación (Spain), and the Science and Technology Facilities Council (United Kingdom). Individuals have received support from the Marie-Curie IEF program (European Union) and the A.P. Sloan Foundation (USA)

    Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

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    The B0B^0-Bˉ0\bar B^0 oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives Δmd=0.493±0.012(stat)±0.009(syst)\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)} ps1^{-1}.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

    Observation of the baryonic decay B \uaf 0 \u2192 \u39bc+ p \uaf K-K+

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    We report the observation of the baryonic decay B\uaf0\u2192\u39bc+p\uafK-K+ using a data sample of 471 7106 BB\uaf pairs produced in e+e- annihilations at s=10.58GeV. This data sample was recorded with the BABAR detector at the PEP-II storage ring at SLAC. We find B(B\uaf0\u2192\u39bc+p\uafK-K+)=(2.5\ub10.4(stat)\ub10.2(syst)\ub10.6B(\u39bc+)) 710-5, where the uncertainties are statistical, systematic, and due to the uncertainty of the \u39bc+\u2192pK-\u3c0+ branching fraction, respectively. The result has a significance corresponding to 5.0 standard deviations, including all uncertainties. For the resonant decay B\uaf0\u2192\u39bc+p\uaf\u3c6, we determine the upper limit B(B\uaf0\u2192\u39bc+p\uaf\u3c6)<1.2 710-5 at 90% confidence level

    Studies of the Cabbibo-Suppressed Decays D+π0+νD^+ \to \pi^0 \ell^+ \nu and D+ηe+νeD^+ \to \eta e^+ \nu_e

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    Using 4.8 fb1^{-1} of data taken with the CLEO II detector, the branching fraction for the Cabibbo-suppressed decay D+π0+νD^+\to\pi^0\ell^+\nu measured relative to the Cabibbo favored decay D+K0ˉ+νD^+\to\bar{K^0}\ell^+\nu is found to be 0.046±0.014±0.0170.046\pm 0.014\pm 0.017. Using VcsV_{cs} and VcdV_{cd} from unitarity constraints, we determine f+π(0)/f+K(0)2=0.9±0.3±0.3| f_+^{\pi}(0)/f_+^K(0)|^2=0.9\pm 0.3\pm 0.3 We also present a 90% confidence level upper limit for the branching ratio of the decay D+ηe+νeD^+ \to \eta e^+\nu_e relative to that for D+π0e+νeD^+ \to \pi^0 e^+\nu_e of 1.5.Comment: 10 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Measurement of BρνB\to \rho\ell\nu Decay and Vub|V_{ub}|

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    Using a sample of 3.3 million Upsilon(4S) -> BBbar events collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR), we measure the branching fraction for B -> rho l nu, |V_ub|, and the partial rate (Delta Gamma) in three bins of q^2 = (p_B-p_rho)^2. We find B(B^0 -> rho^- l^+ nu)=(2.69 +- 0.41^+0.35_-0.40 +- 0.50) 10^-4, |V_ub|=(3.23 +- 0.24^+0.23_-0.26 +- 0.58) 10^-3, Delta Gamma (0 < q^2 < 7 GeV^2/c^4) =(7.6 +- 3.0 ^+0.9_-1.2 +- 3.0) 10^-2 ns^-1, Delta Gamma (7 < q^2 < 14 GeV^2/c^4) =(4.8 +- 2.9 ^+0.7_-0.8 +- 0.7) 10^-2 ns^-1, and Delta Gamma (14 < q^2 < 21 GeV^2/c^4) = (7.1 +- 2.1^+0.9_-1.1 +- 0.6)10^-2 ns^-1. The quoted errors are statistical, systematic, and theoretical. The method is sensitive primarily to B -> rho l nu decays with leptons in the energy range above 2.3 GeV. Averaging with the previously published CLEO results, we obtain B(B^0 -> rho^- l^+ nu) = (2.57 +- 0.29^+0.33_-0.46 +- 0.41) 10^-4 and |V_{ub}| = (3.25 +- 0.14 ^+0.21_-0.29 +- 0.55) 10^-3.Comment: 35 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    Were New Labour’s cultural policies neo-liberal?

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    This article assesses the cultural policies of ‘New Labour’, the UK Labour government of 1997–2010. It takes neo-liberalism as its starting point, asking to what extent Labour’s cultural policies can be validly and usefully characterised as neo-liberal. It explores this issue across three dimensions: corporate sponsorship and cuts in public subsidy; the running of public sector cultural institutions as though they were private businesses; and a shift in prevailing rationales for cultural policy, away from cultural justifications, and towards economic and social goals. Neo-liberalism is shown to be a significant but rather crude tool for evaluating and explaining New Labour’s cultural policies. At worse, it falsely implies that New Labour did not differ from Conservative approaches to cultural policy, downplays the effect of sociocultural factors on policy-making, and fails to differentiate varying periods and directions of policy. It does, however, usefully draw attention to the public policy environment in which Labour operated, in particular the damaging effects of focusing, to an excessive degree, on economic conceptions of the good in a way that does not recognise the limitations of markets as a way of organising production, circulation and consumption
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