3,198 research outputs found

    Searches for LFV and LNV Decays at LHCb

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    The paper presents the latest progress on the searches for Lepton Number Violating (LNV) B Meson decays, the Lepton Flavour Violating (LFV) decay \Ptau^- \to \Pmu^-\Pmu^-\Pmu^+, and the Lepton and Baryon Number Violating (LNV and BNV) decays \Ptau^- \to \mu^+ \mu^- \APproton and \Ptau^- \to \mu^- \mu^- \Pproton at the LHCb. These searches have been performed at a hadron collider for the first time. In the absence of signal we put upper limits, which are as follows: B(τ−→μ−μ−μ+)<6.3×10−8\mathcal{B}(\tau^- \to \mu^- \mu^- \mu^+) < 6.3 \times 10^{-8}, \mathcal{B}(\Ptau^- \to \mu^- \mu^+ \APproton) < 3.4 \times 10^{-7}, \mathcal{B}(\Ptau^- \to \mu^- \mu^- \Pproton) < 4.4 \times 10^{-7} at 90% CL.Comment: 9 pages, 5 figures, Proceedings of CKM 2012, the 7th International Workshop on the CKM Unitarity Triangl

    Long-distance effects in B→K∗ℓℓB\to K^*\ell\ell from Analyticity

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    We discuss a novel approach to systematically determine the long-distance contribution to B→K∗ℓℓB\to K^*\ell\ell decays in the kinematic region where the dilepton invariant mass is below the open charm threshold. This approach provides the most consistent and reliable determination to date and can be used to compute Standard Model predictions for all observables of interest, including the kinematic region where the dilepton invariant mass lies between the J/ψJ/\psi and the ψ(2S)\psi(2S) resonances. We illustrate the power of our results by performing a New Physics fit to the Wilson coefficient C9C_9. This approach is systematically improvable from theoretical and experimental sides, and applies to other decay modes of the type B→VℓℓB\to V\ell\ell, B→PℓℓB\to P\ell\ell and B→VγB\to V\gamma.Comment: 10 pages, 5 figure

    ML with PTIME complexity guarantees

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    Implicit Computational Complexity is a line of research where the possibility to inference a valid property for a program implies that the program runs in particular complexity class. Soft type systems are one of the research threads within the field. We present here a soft type system with ML-like polymorphism that enjoys decidable typechecking, type inference and typability problems and gives polynomial time computational guarantees for the running time of typed programs

    Increasing Quality of the Corpus of Frequency Dictionary of Contemporary Polish for Morphosyntactic Tagging of the Polish Language

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    The paper is devoted to the issue of correction of the erroneous and ambiguous corpus of Frequency Dictionary of Contemporary Polish (FDCP) and its application to morphosyntactic tagging of the Polish language. Several stages of corpus transformation are presented and baseline part-of-speech tagging algorithms are evaluated, too

    A Case Study of Algorithms for Morphosyntactic Tagging of Polish Language

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    The paper presents an evaluation of several part-of-speech taggers, representing main tagging algorithms, applied to corpus of frequency dictionary of the contemporary Polish language. We report our results considering two tagging schemes: IPI PAN positional tagset and its simplified version. Tagging accuracy is calculated for different training sets and takes into account many subcategories (accuracy on known and unknown tokens, word segments, sentences etc.) The comparison of results with other inflecting and analytic languages is done. Performance aspects (time demands) of used tagging tools are also discussed

    Restricted Positive Quantification Is Not Elementary

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    We show that a restricted variant of constructive predicate logic with positive (covariant) quantification is of super-elementary complexity. The restriction is to limit the number of eigenvariables used in quantifier introductions rules to a reasonably usable level. This construction suggests that the known non-elementary decision algorithms for positive logic may actually be best possible

    Physics Opportunities with the FCC-hh Injectors

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    In this chapter we explore a few examples of physics opportunities using the existing chain of accelerators at CERN, including potential upgrades. In this context the LHC ring is also considered as a part of the injector system. The objective is to find examples that constitute sensitive probes of New Physics that ideally cannot be done elsewhere or can be done significantly better at theCERN accelerator complex. Some of these physics opportunities may require a more flexible injector complex with additional functionality than that just needed to inject protons into the FCC-hh at the right energy, intensity and bunch structure. Therefore it is timely to discuss these options concurrently with the conceptual design of the FCC-hh injector system.Comment: 13 pages, chapter 5 in Physics at the FCC-hh, a 100 TeV pp collide
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