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91.
The ratio of the B+ B- and B0B0 production rates in e+ e- annihilation is computed as a function of the B meson velocity and BB*pi coupling constant, using a nonrelativistic effective field theory. 相似文献
92.
J. Heber C. Mühlig W. Triebel N. Danz R. Thielsch N. Kaiser 《Applied Physics A: Materials Science & Processing》2003,76(1):123-128
Fluorescence experiments have been performed to study the interaction of 193-nm laser radiation with dielectric thin films
of LaF3, AlF3, and MgF2. Spectral- and time-resolved measurements reveal the presence of cerium in LaF3 and the influence of hydrocarbons in MgF2 and LaF3. Virtually no fluorescence response is observable in the case of AlF3. Supplementary measurements on multilayer stacks confirm the contribution of hydrocarbon and cerium emission in high-reflective
UV mirrors upon ArF excimer laser irradiation. Energy density dependent measurements indicate a linear absorption process
as the origin of UV laser induced fluorescence in LaF3. Luminescence calculations are applied as a helpful tool in order to account for interference effects that are inherently
to be found in the multilayer emission spectra.
Received: 21 May 2002 / Accepted: 23 May 2002 / Published online: 10 September 2002
RID="*"
ID="*"Corresponding author. Fax: +49-3641/807-601, E-mail: heber@iof.fraunhofer.de 相似文献
93.
Tokarev Yu. V. Alimov V. A. Komrakov G. P. Boiko G. N. Rietveld M. T. Rodriguez P. Bougeret J.-L. Kaiser M. L. Goetz K. 《Radiophysics and Quantum Electronics》2001,44(10):751-762
Results of the 1999 experiments on receiving radio-frequency signals from the SURA and EISCAT facilities on the WIND spacecraft at 5475 kHz are presented. Power and frequency distortions imposed by near-Earth plasmas on the response of SURA-EISCAT, an active decameter radio interferometer with a superlong baseline of 2000 km, are studied. Quasi-oscillatory variations in the intensity of the received radiation with a period of several tenths of a second and the corresponding maximum in the intensity fluctuation spectrum are observed during synchronized operation of the facilities under both quiet and perturbed geophysical conditions including the occurrence of mid-latitude F spread. Variations in the mean frequency of the spectral line both because of the motion of the spacecraft and the large-scale traveling ionospheric disturbances are detected. The obtained results are compared with the modern theoretical concept of propagation of short radio waves in a randomly irregular ionospheric plasma. The possibility to realize the limiting angular resolution of a ground-based decameter interferometer with a superlong baseline for observations of discrete space radio sources is discussed. 相似文献
94.
Ralf Kaiser 《Czechoslovak Journal of Physics》2000,50(5):693-695
Volume Contents
Contents of the Supplement S1 to Vol. 50 (2000) 相似文献95.
Yaouanc A Dalmas De Reotier P Gygax FN Schenck A Amato A Baines C Gubbens PC Kaiser CT de Visser A Keizer RJ Huxley A Menovsky AA 《Physical review letters》2000,84(12):2702-2705
The magnetic response of the heavy fermion superconductor UPt3 has been investigated on a microscopic scale by muon Knight shift studies. Two distinct and isotropic Knight shifts have been found for the field in the basal plane. While the volume fractions associated with the two Knight shifts are approximately equal at low and high temperatures, they show a dramatic and opposite temperature dependence around T(N). Our results are independent on the precise muon localization site. We conclude that UPt3 is characterized by a two component magnetic response. 相似文献
96.
P. Rose T. Richter B. Terhalle J. Imbrock F. Kaiser C. Denz 《Applied physics. B, Lasers and optics》2007,89(4):521-526
We investigate the formation of fundamental discrete solitons and dipole-mode gap solitons in triangular photonic lattices
imprinted in photorefractive nonlinear media. These lattices are strongly affected by the photorefractive anisotropy, resulting
in orientation-dependent refractive index structures with reduced symmetry. It is demonstrated that two different orientations
of the lattice wave enable the formation of fundamental discrete solitons in the total internal reflection gap. Furthermore,
it is shown that one lattice orientation additionally supports dipole-mode solitons in the Bragg reflection gap. The experimental
results are corroborated by numerical simulations using the full anisotropic model.
PACS 42.65.Tg; 42.65.Wi; 42.70.Qs 相似文献
97.
Scales in nuclear matter: Chiral dynamics with pion nucleon form factors<Superscript>⋆</Superscript>
N. Kaiser M. Mühlbauer W. Weise 《The European Physical Journal A - Hadrons and Nuclei》2007,31(1):53-60
A systematic calculation of nuclear matter is performed which includes the long-range correlations between nucleons arising
from one- and two-pion exchange. Three-body effects from 2π exchange with excitations of virtual Δ(1232)-isobars are also
taken into account in our diagrammatic calculation of the energy per particle ˉ(k
f). In order to eliminate possible high-momentum components from the interactions we introduce at each pion-baryon vertex a
form factor of monopole type. The empirical nuclear matter saturation point, ρ0 ≃ 0.16fm^-3, ˉ0 ≃ - 16MeV, is well reproduced with a monopole mass of Λ ≃ 4πf
π ≃ 1.16GeV. As in the recent approach based on the universal low-momentum NN potential V
low-k, the inclusion of three-body effects is crucial in order to achieve saturation of nuclear matter. We demonstrate that the
dependence of the pion exchange contributions to ˉ(k
f) on the “resolution” scale Λ can be compensated over a wide range of Λ by counterterms with two “running” contact couplings.
As a further application we study the in-medium chiral condensate 〈ˉq〉(ρ) beyond the linear density approximation. For ρ ⩽ 1.5ρ0 we find small corrections from the derivative dˉ(k
f)/dm
π, which are stable against variations of the monopole regulator mass Λ. 相似文献
98.
99.
M. Chevrollier N. Mercadier W. Guerin R. Kaiser 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,58(2):161-165
The multiple scattering of photons in a hot, resonant, atomic vapor is investigated and shown to exhibit a Lévy flight-like
behavior. Monte Carlo simulations give insights into the frequency redistribution process that originates the long steps characteristic
of this class of random walk phenomena. 相似文献
100.
We construct an effective Lagrangian involving pions,ρ andω mesons. We calculate the bulk properties of hedgehog Skyrmions in this model. Canonical quantization is performed to project onto states of good spin and isospin, and various approximations going into the calculation of the moment of inertia are discussed in extensio. We find that theω-excitations are clearly dominating the excitations of theρ field. 相似文献