233 research outputs found

    Рецензируемые издания как элемент государственной системы научной аттестации

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    The aim of the work is to analyze peer-reviewed scientific publications as an element of the state system of scientific attestation in order to improve its regulatory legal regulation. The article shows the directions of improving the formation of the list of peer-reviewed scientific publications. Suggestions are made to optimize the formation of the list of peer-reviewed scientific publications, namely, to form a list of peer-reviewed scientific publications by groups of scientific specialties without detailing by branches of science, as well as to improve some regulatory legal acts in terms of requirements for peer-reviewed scientific publications.Проводится анализ рецензируемых научных изданий как элемента государственной системы научной аттестации на предмет совершенствования его нормативного правового регулирования. Показываются направления совершенствования формирования перечня рецензируемых научных изданий. Даются предложения по оптимизации формирования перечня рецензируемых научных изданий, а именно по формированию перечня рецензируемых научных изданий по группам научных специальностей без детализации по отраслям науки, а также по совершенствованию некоторых нормативных правовых актов в части требований к рецензируемым научным изданиям

    Search for a Light Higgs Boson in Single-Photon Decays of ϒ(1S) Using ϒ(2S)→π+^{+}π^{-}ϒ(1S) Tagging Method

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    We search for a light Higgs boson (A0^{0}) decaying into a τ+^{+}τ^{-} or μ+^{+}μ^{-} pair in the radiative decays of Υ(1S). The production of Υ(1S) mesons is tagged by Υ(2S)→π+^{+}π^{-}Υ(1S) transitions, using 158×106^{6} Υ(2S) events accumulated with the Belle detector at the KEKB asymmetric energy electron positron collider. No significant A0^{0} signals in the mass range from the τ+^{+}τ^{-} or μ+^{+}μ^{-} threshold to 9.2 GeV/c2^{2} are observed. We set the upper limits at 90% credibility level (C.L.) on the product branching fractions for Υ(1S)→γA0^{0} and A0^{0}→τ+^{+}τ^{-} varying from 3.8×106^{-6} to 1.5×104^{-4}. Our results represent an approximately twofold improvement on the current world best upper limits for the Υ(1S)→γA0^{0}(→τ+^{+}τ^{-}) production. For A0^{0}→μ+^{+}μ^{-}, the upper limits on the product branching fractions for Υ(1S)→γA0^{0} and A0^{0}→μ+^{+}μ^{-} are at the same level as the world average limits, and vary from 3.1×107^{-7} to 1.6×105^{-5}. The upper limits at 90% credibility level on the Yukawa coupling fΥ(1S) and mixing angle sin θA0_{A0} are also given

    First measurement of the Michel parameter ξ\xi^\prime in the τμνˉμντ\tau^-\to\mu^-\bar{\nu}_\mu\nu_\tau decay at Belle

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    We report the first measurement of the Michel parameter ξ\xi^\prime in the τμνˉμντ\tau^-\to\mu^-\bar{\nu}_\mu\nu_\tau decay with a new method proposed just recently. The measurement is based on the reconstruction of the τμνˉμντ\tau^-\to\mu^-\bar{\nu}_\mu\nu_\tau events with subsequent muon decay-in-flight in the Belle central drift chamber. The analyzed data sample of 988fb1988\,\text{fb}^{-1} collected by the Belle detector corresponds to approximately 912×106912\times10^6 τ+τ\tau^+ \tau^- pairs. We measure ξ=0.22±0.94(stat)±0.42(syst)\xi^\prime=0.22\pm0.94(\text{stat})\pm0.42(\text{syst}), which is in agreement with the Standard Model prediction of ξ=1\xi^\prime=1. Statistical uncertainty dominates in this study, being a limiting factor, while systematic uncertainty is well under control. Our analysis proved the practicability of this promising method and its prospects for further precise measurement in future experiments.Comment: 6 pages, 4 figures, submitted to Phys. Rev. Let

    Search for X(3872)π+ππ0X(3872)\to\pi^+\pi^-\pi^0 at Belle

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    We present a search for the decay X(3872)π+ππ0X(3872) \to \pi^+\pi^-\pi^0 in the (772±11)×106(772\pm11)\times10^6 Υ(4S)BBˉ\Upsilon(4S)\to B \bar B data sample collected at the Belle detector, where the X(3872)X(3872) is produced in B±K±X(3872)B^{\pm}\to K^{\pm}X(3872) and B0KS0X(3872)B^{0}\to K_{S}^0 X(3872) decays. We do not observe a signal, and set 90\% credible upper limits for two different models of the decay processes: if the decay products are distributed uniformly in phase space, B(X(3872)π+ππ0)<1.3%\mathcal{B}(X(3872) \to \pi^+\pi^-\pi^0) < 1.3\%; if M(π+π)M(\pi^+\pi^-) is concentrated near the mass of the D0Dˉ0D^0 \bar D^0 pair in the process X(3872)D0Dˉ0+c.c.D0Dˉ0π0π+ππ0X(3872)\to D^0\bar{D}^{*0}+c.c.\to D^0 \bar D^{0}\pi^0\to\pi^+ \pi^- \pi^0, B(X(3872)π+ππ0)<1.2×103\mathcal{B}(X(3872) \to \pi^+\pi^-\pi^0) < 1.2\times10^{-3}

    Search for the lepton flavour violating decays B+K+τ±B^{+} \to K^{+} \tau^\pm \ell^\mp (=e,μ\ell = e, \mu) at Belle

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    We present a search for the lepton-flavour-violating decays B+K+τ±B^+ \to K^+ \tau^\pm \ell^\mp, with =(e,μ)\ell = (e, \mu), using the full data sample of 772×106772 \times 10^6 BBB\overline{B} pairs recorded by the Belle detector at the KEKB asymmetric-energy e+ee^+ e^- collider. We use events in which one BB meson is fully reconstructed in a hadronic decay mode. We find no evidence for B±K±τB^\pm \to K^\pm \tau \ell decays and set upper limits on their branching fractions at the 90% confidence level in the (1(1-3)×1053) \times 10^{-5} range. The obtained limits are the world's best results.Comment: 14 pages, 6 figure

    Search for charged-lepton flavor violation in Υ(2S)τ±\Upsilon(2S) \to \ell^\mp\tau^\pm (=e,μ\ell=e,\mu) decays at Belle

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    We report a search for the charged-lepton flavor violation in Υ(2S)τ±\Upsilon(2S) \to \ell^\mp\tau^\pm (=e,μ\ell=e,\mu) decays using a 25 fb125~\mathrm{fb}^{-1} Υ(2S)\Upsilon(2S) sample collected by the Belle detector at the KEKB e+ee^{+}e^{-} asymmetric-energy collider. We find no evidence for a signal and set upper limits on the branching fractions (B\mathcal{B}) at 90%\% confidence level. We obtain the most stringent upper limits: B(Υ(2S)μτ±)<0.26×106\mathcal{B}(\Upsilon(2S) \to \mu^{\mp}\tau^{\pm}) < 0.26 \times 10^{-6} and B(Υ(2S)eτ±)<1.02×106\mathcal{B}(\Upsilon(2S) \to e^{\mp}\tau^{\pm}) < 1.02 \times 10^{-6}.Comment: 11 pages, 3 figures, Submitted to JHE

    Measurement of Angular Coefficients of BˉDνˉ\bar{B} \to D^* \ell \bar{\nu}_\ell: Implications for Vcb|V_{cb}| and Tests of Lepton Flavor Universality

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    We measure the complete set of angular coefficients JiJ_i for exclusive BˉDνˉ\bar{B} \to D^* \ell \bar{\nu}_\ell decays (=e,μ\ell = e, \mu). Our analysis uses the full 711fb1711\,\mathrm{fb}^{-1} Belle data set with hadronic tag-side reconstruction. The results allow us to extract the form factors describing the BDB \to D^* transition and the Cabibbo-Kobayashi-Maskawa matrix element Vcb|V_{\rm cb}|. Using recent lattice QCD calculations for the hadronic form factors, we find Vcb=(41.0±0.7)×103|V_{\rm cb}| = (41.0 \pm 0.7) \times 10^3 using the BGL parameterization, compatible with determinations from inclusive semileptonic decays. We search for lepton flavor universality violation as a function of the hadronic recoil parameter ww, and investigate the differences of the electron and muon angular distributions. We find no deviation from Standard Model expectations

    Study of B\overline{B}0^{0} →D+^{+}h^{–} (h=K/π) decays at Belle

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    We present a measurement of the branching fractions of the Cabibbo favored B\overline{B}0^{0} →D+^{+}π^{–} and the Cabibbo suppressed B\overline{B}0^{0} →D+^{+}K^{–} decays. We find B(B\overline{B}0^{0} →D+^{+}π^{–})=(2.48±0.01±0.09±0.04)×103^{–3} and B(B\overline{B}0^{0} →D+^{+}K^{–})=(2.03±0.05±0.07±0.03)×104^{–4} decays, where the first uncertainty is statistical, the second is systematic, and the third uncertainty is due to the D+^{+}→K^{–} π+^{+}π^{–} branching fraction. The ratio of branching fractions of B\overline{B}0^{0} →D+^{+}K^{–} and B\overline{B}0^{0} →D+^{+}π^{–} is measured to be RD^{D}=[8.19±0.20(stat)±0.23(syst)]×102^{–2}. These measurements are performed using the full Belle dataset, which corresponds to 772×106^{6} BB\overline{B} pairs and use the Belle II software framework for data analysis

    First test of lepton flavor universality in the charmed baryon decays Ω0^{0}c_{c} → Ω^{-}+^{+}ν_{ℓ} using data of the Belle experiment

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    We present the first observation of the Ω0c→Ω−μ+νμ decay and present measurements of the branching fraction ratios of the Ω0c→Ω−ℓ+νℓ decays compared to the reference mode Ω0c→Ω−π+, (ℓ=e or μ). This analysis is based on 89.5  fb−1, 711  fb−1, and 121.1  fb−1 data samples collected with the Belle detector at the KEKB asymmetric-energy e+e− collider at the center-of-mass energies of 10.52 GeV, 10.58 GeV, and 10.86 GeV, respectively. The Ω0c signal yields are extracted by fitting MΩℓ and MΩπ spectra. The branching fraction ratios B(Ω0c→Ω−e+νe)/B(Ω0c→Ω−π+) and B(Ω0c→Ω−μ+νμ)/B(Ω0c→Ω−π+) are measured to be 1.98±0.13(stat)±0.08(syst) and 1.94±0.18(stat)±0.10(syst), respectively. The ratio of B(Ω0c→Ω−e+νe)/B(Ω0c→Ω−μ+νμ) is measured to be 1.02±0.10(stat)±0.02(syst), which is consistent with the expectation of lepton flavor universality
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