461 research outputs found

    Search for f1(1285)π+ππ0f_1(1285) \to \pi^+\pi^-\pi^0 decay with VES detector

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    The isospin violating decay f1(1285)π+ππ0f_1(1285)\to\pi^+\pi^-\pi^0 has been studied at VES facility. This study is based at the statistics acquired in πBe\pi^- Be interactions at 27, 36.6 and 41 GeV/c in diffractive reaction πN(f1π)N\pi^- N \to (f_1 \pi^-) N. The f1(1285)π+ππ0f_1(1285) \to \pi^+\pi^-\pi^0 decay is observed. The ratio of decay probabilities BR(f1(1285)π+ππ0)BR(f_1(1285) \to \pi^+\pi^-\pi^0) to BR(f1(1285)ηπ+π)BR(ηγγ)BR(f_1(1285) \to \eta \pi^+\pi^-) \cdot BR(\eta \to \gamma\gamma) is 1.4\sim\:1.4%.Comment: 10 pages, 8 figures, presented at XII Conference on Hadron Spectroscop

    Патогенетичні фактори розвитку аутоімунних захворювань. Сучасні підходи до їх лікування

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    In experimental models of pathologies of autoimmune genesis there was grounded the possibility and confirmed the efficiency of using the products of fetoplacental complex. There was tested their ability to activate T-regulatory immunity link and normalize cell indices in experimental animals. More pronounced immune correcting potential of cryopreserved material has been shown at cell and molecular levels. На экспериментальных моделях патологий аутоиммунного генеза обоснована возможность и доказана эффективность применения продуктов фетоплацентарного комплекса. Продемонстрирована их способность к  активации Т-регуляторного звена иммунитета и нормализации клинических показателей экспериментальных животных. Показан более выраженный  иммунокорригирующий потенциал криоконсервированного материала на клеточном и молекулярном уровнях.На експериментальних моделях патологій аутоімунного генезу обгрунтована можливість і доведена ефективність застосування продуктів фетоплацентарного комплексу. Продемонстровано їхню здатність до активації Т-регуляторної ланки імунітету і нормалізації клінічних показників експериментальних тварин. Показано більш виражений імунокоригуючий потенціал кріоконсервованого матеріалу на клітинному і молекулярному рівнях

    R & D for collider beauty physics at the LHC

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    We propose an R&D program for the development of a Beauty trigger and innovative elements of the associated spectrometer. A series of short test runs is proposed at the SPS p-pbar Collider with the minimal spectrometer which will allow a credible B signal to be obtained in an invariant mass spectrum of reconstructed B mesons. The program builds on the success of the recent collider run of the P238 Collaboration, in which clean signals from beam-beam interactions were observed in a large silicon strip microvertex detector running 1.5 mm from the circulating beams. A continuing successful R&D program of the type proposed could ultimately lead to a collider experiment at the LHC to study CP Violation and rare B decays

    First observation of Bs -> D_{s2}^{*+} X mu nu decays

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    Using data collected with the LHCb detector in proton-proton collisions at a centre-of-mass energy of 7 TeV, the semileptonic decays Bs -> Ds+ X mu nu and Bs -> D0 K+ X mu nu are detected. Two structures are observed in the D0 K+ mass spectrum at masses consistent with the known D^+_{s1}(2536) and $D^{*+}_{s2}(2573) mesons. The measured branching fractions relative to the total Bs semileptonic rate are B(Bs -> D_{s2}^{*+} X mu nu)/B(Bs -> X mu nu)= (3.3\pm 1.0\pm 0.4)%, and B(Bs -> D_{s1}^+ X munu)/B(Bs -> X mu nu)= (5.4\pm 1.2\pm 0.5)%, where the first uncertainty is statistical and the second is systematic. This is the first observation of the D_{s2}^{*+} state in Bs decays; we also measure its mass and width.Comment: 8 pages 2 figures. Published in Physics Letters

    KLEVER: An experiment to measure BR(KLπ0ννˉK_L\to\pi^0\nu\bar{\nu}) at the CERN SPS

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    Precise measurements of the branching ratios for the flavor-changing neutral current decays KπννˉK\to\pi\nu\bar{\nu} can provide unique constraints on CKM unitarity and, potentially, evidence for new physics. It is important to measure both decay modes, K+π+ννˉK^+\to\pi^+\nu\bar{\nu} and KLπ0ννˉK_L\to\pi^0\nu\bar{\nu}, since different new physics models affect the rates for each channel differently. The goal of the NA62 experiment at the CERN SPS is to measure the BR for the charged channel to within 10%. For the neutral channel, the BR has never been measured. We are designing the KLEVER experiment to measure BR(KLπ0ννˉK_L\to\pi^0\nu\bar{\nu}) to \sim20% using a high-energy neutral beam at the CERN SPS starting in LHC Run 4. The boost from the high-energy beam facilitates the rejection of background channels such as KLπ0π0K_L\to\pi^0\pi^0 by detection of the additional photons in the final state. On the other hand, the layout poses particular challenges for the design of the small-angle vetoes, which must reject photons from KLK_L decays escaping through the beam exit amidst an intense background from soft photons and neutrons in the beam. Background from Λnπ0\Lambda \to n\pi^0 decays in the beam must also be kept under control. We present findings from our design studies for the beamline and experiment, with an emphasis on the challenges faced and the potential sensitivity for the measurement of BR(KLπ0ννˉK_L\to\pi^0\nu\bar{\nu}).Comment: 13 pages, 4 figures. Submitted as input to the 2020 update of the European Strategy for Particle Physics. v2: Included authors unintentionally omitted in v

    Physics beyond the standard model with kaons at NA62

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    The NA62 experiment at CERN Super Proton Synchrotron was designed to measure BR(K+ \u2192 \u3c0+\u3bdv\u304) with an in-fight technique, never used before for this measurement. This decay is characterised by a very precise prediction in the Standard Model. Its branching ratio, which is expected to be less than 10-10, is one of the best candidates to indicate indirect effects of new physics beyond SM at the highest mass scales. NA62 result on K+ \u2192 \u3c0+\u3bdv\u304 from the full 2016 data set is described. Also a search for an invisible dark photon A\u2032 has been performed, exploiting the efficient photon-veto capability and high resolution tracking of the NA62. The signal stems from the chain K+ \u2192 \u3c0+\u3c00 followed by \u3c00 \u2192 A\u2032\u3b3. No significant statistical excess has been identified. Upper limits on the dark photon coupling to the ordinary photon as a function of the dark photon mass have been set, improving on the previous limits over the mass range 60 - 110 MeV/c2

    Externalities and the nucleolus

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    In most economic applications, externalities prevail: the worth of a coalition depends on how the other players are organized. We show that there is a unique natural way of extending the nucleolus from (coalitional) games without externalities to games with externalities. This is in contrast to the Shapley value and the core for which many different extensions have been proposed

    LHCb calorimeters: Technical Design Report

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