1,186 research outputs found

    Aerodynamic Theory of the Oscillating Wing of Finite Span

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    The theory of the oscillating airfoil of infinite span with two-dimensional flow has been developed to a high degree of completeness (ref. 4, 7) In the present theory the oscillating airfoil of finite span is considered with the purpose of introducing the effect, of the trailing vortices and the three dimensional characters of the velocity field, on the aerodynamics forces. General formulae are established for the lift and moment on an elliptic airfoil oscillating in both translation and rotation and the numerical results are presented in tabular and graphical form

    A first measurement of the interaction cross section of the tau neutrino

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    The DONuT experiment collected data in 1997 and published first results in 2000 based on four observed ντ\nu_\tau charged-current (CC) interactions. The final analysis of the data collected in the experiment is presented in this paper, based on 3.6×10173.6 \times 10^{17} protons on target using the 800 GeV Tevatron beam at Fermilab. The number of observed ντ\nu_\tau CC interactions is 9, from a total of 578 observed neutrino interactions. We calculated the energy-independent part of the tau-neutrino CC cross section (ν+νˉ\nu + \bar \nu), relative to the well-known νe\nu_e and νμ\nu_\mu cross sections. The ratio σ(ντ)\sigma(\nu_\tau)/σ(νe,μ)\sigma(\nu_{e,\mu}) was found to be 1.37±0.35±0.771.37\pm0.35\pm0.77. The ντ\nu_\tau CC cross section was found to be 0.72±0.24±0.36×10380.72 \pm 0.24\pm0.36 \times 10^{-38} cm2GeV1^{2}\rm{GeV}^{-1}. Both results are in agreement the Standard Model.Comment: 37 pages, 15 figure

    QCD Corrections to the Top Decay Mode t \ra \tilde{t} \chi^0

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    In supersymmetric theories, the top quark can decay into its scalar partner plus a neutralino, with an appreciable rate. We calculate the O(αs)O(\alpha_s) QCD corrections to this decay mode in the minimal supersymmetric extension of the Standard Model. These corrections can be either positive or negative and increase logarithmically with the gluino mass. For gluino masses below 1 TeV, they are at most of the order of ten percent and therefore, well under control.Comment: 15 pages including 4 figs (using psfig.sty). A few typos have been corrected and some references added. The results for Figs. 3 and 4 are now presented in the dimensional reduction scheme. Version to appear in Phys. Rev.

    Measurement of the Atmospheric Muon Charge Ratio at TeV Energies with MINOS

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    The 5.4 kton MINOS far detector has been taking charge-separated cosmic ray muon data since the beginning of August, 2003 at a depth of 2070 meters-water-equivalent in the Soudan Underground Laboratory, Minnesota, USA. The data with both forward and reversed magnetic field running configurations were combined to minimize systematic errors in the determination of the underground muon charge ratio. When averaged, two independent analyses find the charge ratio underground to be 1.374 +/- 0.004 (stat.) +0.012 -0.010(sys.). Using the map of the Soudan rock overburden, the muon momenta as measured underground were projected to the corresponding values at the surface in the energy range 1-7 TeV. Within this range of energies at the surface, the MINOS data are consistent with the charge ratio being energy independent at the two standard deviation level. When the MINOS results are compared with measurements at lower energies, a clear rise in the charge ratio in the energy range 0.3 -- 1.0 TeV is apparent. A qualitative model shows that the rise is consistent with an increasing contribution of kaon decays to the muon charge ratio.Comment: 16 pages, 17 figure

    Study of Zγ events and limits on anomalous ZZγ and Zγγ couplings in pp̄ collisions at s=1.96TeV

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    We present a measurement of the Zγ production cross section and limits on anomalous ZZγ and Zγγ couplings for form-factor scales of Λ=750 and 1000 GeV. The measurement is based on 138 (152) candidates in the eeγ (μμγ) final state using 320(290)pb-1 of pp̄ collisions at s=1.96TeV. The 95% C.L. limits on real and imaginary parts of individual anomalous couplings are |h10,30Z|<0.23, |h20,40Z|<0.020, |h10,30γ|<0.23, and |h20,40γ|<0.019 for Λ=1000GeV. © 2005 The American Physical Society
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