1,583 research outputs found

    Testing Explanations of the BϕKB\to\phi K^* Polarization Puzzle

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    BϕKB\to\phi K^* (\btos) is three separate decays, one for each polarization of the final-state vector mesons (one longitudinal, two transverse). It is observed that the fraction of transverse decays, \fT, and the fraction of longitudinal decays, \fL, are roughly equal: \fTfL \simeq 1, in opposition to the naive expectation that \fT \ll \fL. If one requires a single explanation of all polarization puzzles, two possibilities remain within the standard model: penguin annihilation and rescattering. In this paper we examine the predictions of these two explanations for \fTfL in \btod decays. In BρρB \to \rho\rho decays, only \bd \to \rho^0\rho^0 can possibly exhibit a large \fTfL. In B decays related by U-spin, we find two promising possibilities: (i) B+K0ρ+B^+ \to K^{*0} \rho^+ (\btos) and B^+ \to \Kbar^{*0} K^{*+} (\btod) and (ii) \bs \to K^{*0} \Kbar^{*0} (\btos) and \bd \to \Kbar^{*0} K^{*0} (\btod). The measurement of \fTfL in these pairs of decays will allow us to test penguin annihilation and rescattering. Finally, it is possible to distinguish penguin annihilation from rescattering by performing a time-dependent angular analysis of \bd \to \Kbar^{*0} K^{*0}.Comment: 15 pages, 2 figures. Added reference and PACS numbers. To appear in PR

    Study of Polarization in B -> VT Decays

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    In this paper, we examine B -> VT decays (V is a vector and T is a tensor meson), whose final-state particles can have transverse or longitudinal polarization. Measurements have been made of B -> \phi K_2^*, and it is found that fT/fL is small, where fT (fL) is the fraction of transverse (longitudinal) decays. We find that the standard model (SM) naively predicts that fT/fL << 1. The two extensions of the naive SM which have been proposed to explain the large fT/fL in B -> \phi K^* -- penguin annihilation and rescattering -- make no firm predictions for the polarization in B -> \phi K_2^*. The two new-physics scenarios, which explain the data in B -> \pi K and the \phi (\rho) K^* polarization measurements, can reproduce the fT/fL data in B -> \phi K_2^* only if the B -> T form factors obey a certain hierarchy. Finally, we present the general angular analysis which can be used to get helicity information using two- and three-body decays.Comment: 15 pages, latex, 3 figures (enclosed), several changes made, conclusions unchanged, publication info adde

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

    Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

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    One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

    Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

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    This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good
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