3,359 research outputs found

    Measurement of the τ-lepton Lifetime at Belle

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    The lifetime of the τ lepton is measured using the process e+e−→τ+τ−, where both τ leptons decay to 3πντ. The result for the mean lifetime, based on 711  fb−1 of data collected with the Belle detector at the ϒ(4S) resonance and 60  MeV below, is τ=(290.17±0.53(stat)±0.33(syst))×10−15  s. The first measurement of the lifetime difference betweenτ+ and τ− is performed. The upper limit on the relative lifetime difference between positive and negative τ leptons is |Δτ|/τ\u3c7.0×10−3 at 90% C.L

    Measurement of the K+μ+νμγK^+\rightarrow{\mu^+}{\nu_{\mu}}{\gamma} decay form factors in the OKA experiment

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    A precise measurement of the vector and axial-vector form factors difference FVFAF_V-F_A in the K+μ+νμγK^+\rightarrow{\mu^+}{\nu_{\mu}}{\gamma} decay is presented. About 95K events of K+μ+νμγK^+\rightarrow{\mu^+}{\nu_{\mu}}{\gamma} are selected in the OKA experiment. The result is FVFA=0.134±0.021(stat)±0.027(syst)F_V-F_A=0.134\pm0.021(stat)\pm0.027(syst). Both errors are smaller than in the previous FVFAF_V-F_A measurements.Comment: 9 pages, 8 figure

    STUDY OF COMPOSITION OF PHENOLIC COMPOUNDS OF HERBAL REPERTORY “EUPHRASIN” BY HPLC METHOD

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    The study refers to the research of phenolic compounds of herbal repertory "Euphrasin". This research was done with the HPLC method and was studied with "G1LSTON" instrument. 17 peak identities were monitored in alcohol extracts of herbal repertory "Euphrasin". Compared with reliable samples 15 compounds that belong to the group of flavonoids, phenolcarbonic acids and tannins were identified. Hyperoside (6,91 %), gallic acid (25,88 %) and tannin (17,07 %) are dominant components

    First study of \eta_c, \eta(1760) and X(1835) production via \eta'\pi^+\pi^- final states in two-photon collisions

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    The invariant mass spectrum of the \eta' \pi^+ \pi^- final state produced in two-photon collisions is obtained using a 673 fb^{-1} data sample collected in the vicinity of the \Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We observe a clear signal of the \eta_c and measure its mass and width to be M(\eta_c)=(2982.7 +- 1.8(stat) +- 2.2(syst) +- 0.3(model)) MeV/c^2 and \Gamma(\eta_c) = (37.8^{+5.8}_{-5.3}(stat) +- 2.8(syst) +- 1.4(model)) MeV/c^2. The third error is an uncertainty due to possible interference between the \eta_c and a non-resonant component. We also report the first evidence for \eta(1760) decay to \eta' \pi^+ \pi^-; we find two solutions for its parameters, depending on the inclusion or not of the X(1835), whose existence is of marginal significance in our data. From a fit to the mass spectrum using coherent X(1835) and \eta(1760) resonant amplitudes, we set a 90% confidence level upper limit on the product \Gamma_{\gamma\gamma} \BR (\eta' \pi^+ \pi^-) for the X(1835).Comment: 13 pages, 7 figures, submitted to PR

    КООРДИНАЦИЯ ПО ГОРИЗОНТАЛИ

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    The problems of research and educational centers are considered by the authors from the aspect of strategic development of higher education. Using the example of cooperation of Moscow University of Railway Engineering and JSC Russian Railways, the authors study possibilities of extending of R&D on the basis of modernized forms of organization and university traditions. The proposed approach envisages improvement of training of research and academic staff, of students’ stages, of all the system of training of future professionals of railways.Проблемы научно-образовательных центров оцениваются авторами с точки зрения стратегического развития высшего образования. На основе сотрудничества МИИТ с ОАО «РЖД» рассматривается возможность расширения объемов научно-исследовательских и опытно-конструкторских работ (НИОКР) за счет более совершенных организационных форм и сложившихся ранее университетских традиций. Предлагаемый подход предусматривает улучшение качества подготовки научных и преподавательских кадров, студенческой практики, всей системы воспитания будущих специалистов для железнодорожной отрасли.

    Актуальные вопросы подготовки кадров в области беспилотных авиационных систем

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       The legal regulation, and hence, the training system in the field of unmanned aircraft systems (UAS) in the Russian Federation, the European Union and the United States is based on the unmanned aerial vehicles (UAV) rating with respect to UAS maximum take-off weight (MTOW) and their purpose (method of use). In this regard, small-unmanned aircraft (sUAS) are identified – in our country up to 30 kg, in the EU and the USA up to 55 lbs (25 kg) and UAV with larger weight. In the USA and Europe, the training of remote pilots for sUAS is differentiated based on the degree of risk that UAV can represent for public safety. Thus, the training of remote pilots to use UAVs with MTOW less than 25 kg (55 lbs) in a sparsely populated area during daylight hours under the conditions of visual range is conducted in the online format, the result of which is taking tests. In the United States and Europe, the UAV application with MTOW more than 25 kg (55 lbs) or performing UAV operations, presenting a potential risk for public safety, requires more comprehensive and long-term training of remote pilots. In the Russian Federation, UAS personnel training is conducted in educational organizations according to different programs, which vary significantly depending on a specific type of aviation UAVs refers to: State, Civil or Experimental. UAS personnel training programs for various aviation types are not harmonized, which leads to the failure to credit previously received education in training to perform activities in another aviation type. The article describes the analysis results of the international and national experience, perspectives for the development of the UAS personnel training system, as well as formulates the proposals concerning further development of the national system for UAS specialists training.   Правовое регулирование, а значит и система подготовки кадров в области беспилотных авиационных систем, в Российской Федерации, Европейском союзе и США строится исходя из классификации беспилотных воздушных судов по максимальной взлетной массе и назначению (способу использования) беспилотных авиационных систем. В этом смысле выделяют малые беспилотные воздушные суда – у нас в стране до 30 кг, в ЕС и США до 55 фунтов (25 кг) и беспилотные воздушные суда с большим весом. В США и Европе подготовку внешних пилотов для малых беспилотных воздушных судов дифференцируют исходя из степени риска, которую беспилотные воздушные суда могут представлять для окружающих. Так, подготовка внешних пилотов к использованию беспилотных воздушных судов максимальной взлетной массой менее 25 кг (55 фунтов) в малолюдной местности в дневное время в условиях визуальной видимости проводится в виде онлайн-обучения, итогом которого является сдача тестов. Использование беспилотных воздушных судов максимальной взлетной массой более 25 кг (55 фунтов) или выполнение операций с использованием беспилотных воздушных судов, представляющих потенциальный риск для окружающих, в США и Европе требует иной, более сложной и продолжительной подготовки внешних пилотов. В Российской Федерации подготовка кадров в области беспилотных авиационных систем осуществляется в образовательных организациях по разным программам, которые значительно отличаются в зависимости от принадлежности беспилотных воздушных судов к определенному виду авиации: государственной, гражданской или экспериментальной. Программы подготовки кадров в области беспилотных авиационных систем для различных видов авиации не гармонизированы, что приводит к невозможности зачесть ранее полученное образование при подготовке к выполнению деятельности в другом виде авиации. В статье представлены результаты анализа международного и отечественного опыта, перспектив развития системы подготовки кадров в области беспилотных авиационных систем, а также сформулированы предложения по дальнейшему развитию отечественной системы подготовки специалистов в области беспилотных авиационных систем

    Evidence for Direct CP Violation in B±ηh±B^\pm \to \eta h^\pm and Observation of B0ηK0B^0 \to \eta K^0

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    We report measurements of the branching fractions and CP asymmetries for B^+- -> eta h^+- (h = K or pi) and the observation of the decay B^0 -> eta K^0 from the final data sample of 772x10^6 BBbar pairs collected with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. The measured branching fractions are Br(B^+- -> eta K^+-) = (2.12 +- 0.23 +- 0.11)x10^-6}, Br(B^+- -> eta pi^+-) = (4.07 +- 0.26 +- 0.21)x10^{-6} and Br(B^0 -> eta K^0) = (1.27^{+0.33}_{-0.29} +- 0.08)x10^-6, where the last decay is observed for the first time with a significance of 5.4 standard deviations (\sigma). We also find evidence for CP violation in the charged B modes, A_{CP}(B^+- -> eta K^+-) = -0.38 +- 0.11 +- 0.01 and A_{CP}(B^+- -> eta pi^+- = -0.19 +- 0.06 +- 0.01 with significances of 3.8 sigma and 3.0 sigma, respectively. For all measurements, the first and second uncertainties are statistical and systematic, respectively.Comment: 6 pages, 3 figures, 1 tabl

    Precision measurement of charged pion and kaon differential cross sections in electron-positron annihilation at Q = 10.52 GeV

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    Measurements of inclusive differential cross sections for charged pion and kaon production in electron-positron annihilation have been carried out at a center-of-mass energy of Q = 10.52 GeV. The measurements were performed with the Belle detector at the KEKB electron-positron collider using a data sample containing 113 million e+e- -> qqbar events, where q={u,d,s,c}. We present charge-integrated differential cross sections d\sigma_h+-/dz for h+- = pi+-, K+- as a function of the relative hadron energy z = 2*E_h / sqrt{s} from 0.2 to 0.98. The combined statistical and systematic uncertainties for pi+- (K+-) are 4% (4%) at z ~ 0.6 and 15% (24%) at z ~ 0.9. The cross sections are the first measurements of the z-dependence of pion and kaon production for z > 0.7 as well as the first precision cross section measurements at a center-of-mass energy far below the Z^0 resonance used by the experiments at LEP and SLC.Comment: 7 pages, 3 figures. Ancillary file including all cross section and uncertainty values with 10 pages, 5 figure

    Search for leptonic decays of D0 mesons

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    We search for the flavor-changing neutral current decays D0\to mu+mu- and D0\to e+e-, and for the lepton-flavor violating decays D0\to e\pm mu\mp using 660 fb^-1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. We find no evidence for any of these decays. We obtain significantly improved upper limits on the branching fractions: B(D0\to mu+mu-)<1.4x10-7, B(D0\to e+e-)<7.9x10-8, and B(D0\to e+mu-)+B(D0\to mu+e-)<2.6x10-7 at 90% confidence level.Comment: 6 pages, 3 figure
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