1,186 research outputs found
Aerodynamic Theory of the Oscillating Wing of Finite Span
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
The DONuT experiment collected data in 1997 and published first results in
2000 based on four observed charged-current (CC) interactions. The
final analysis of the data collected in the experiment is presented in this
paper, based on protons on target using the 800 GeV
Tevatron beam at Fermilab. The number of observed 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 (), relative to the well-known and cross sections. The
ratio / was found to be
. The CC cross section was found to be cm. Both results are in
agreement the Standard Model.Comment: 37 pages, 15 figure
A New Upper Limit for the Tau-Neutrino Magnetic Moment
Using a prompt neutrino beam in which a nu_tau component was identified for
the first time, the nu_tau magnetic moment was measured based on a search for
an anomalous increase in the number of neutrino-electron interactions. One such
event was observed when 2.3 were expected from background processes, giving an
upper 90% confidence limit of 3.9x10^-7 Bohr magnetons.Comment: 9 pages; 1 figur
QCD Corrections to the Top Decay Mode t \ra \tilde{t} \chi^0
In supersymmetric theories, the top quark can decay into its scalar partner
plus a neutralino, with an appreciable rate. We calculate the 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
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
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First Direct Observation of Muon Antineutrino Disappearance
This Letter reports the first direct observation of muon antineutrino disappearance. The MINOS experiment has taken data with an accelerator beam optimized for ν̅ _μ production, accumulating an exposure of 1.71×10^(20) protons on target. In the Far Detector, 97 charged current ν̅ _μ events are observed. The no-oscillation hypothesis predicts 156 events and is excluded at 6.3σ. The best fit to oscillation yields |Δm̅ 2|= [3.36=_(-0.40)^(+0.46)(stat)±0.06(syst)]x10^(-3)eV^2,sin^2(2θ̅)=0.86 _(-0.12)^(+0.11)(stat)±0.01(syst). The MINOS ν̅ _μ and ν̅ _μ measurements are consistent at the 2.0% confidence level, assuming identical underlying oscillation parameters
Study of Zγ events and limits on anomalous ZZγ and Zγγ couplings in pp̄ collisions at s=1.96TeV
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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