44,140 research outputs found
Parton Distributions Functions of Pion, Kaon and Eta pseudoscalar mesons in the NJL model
Parton distributions of pseudoscalar pi,K and eta mesons obtained within the
NJL model using the Pauli-Villars regularization method are analyzed in terms
of LO and NLO evolution, and the valence sea quark and gluon parton
distributions for the pion are obtained at Q^2 = 4 GeV^2 and compared to
existing parametrizations at that scale. Surprisingly, the NLO order effects
turn out to be small compared to the LO ones. The valence distributions are in
good agreement with experimental analyses, but the gluon and sea distributions
come out to be softer in the high-x region and harder in the low-x region than
the experimental analyses suggest.Comment: (Latex, epsfig) 17 pages, 7 figure
Stationary configurations of two extreme black holes obtainable from the Kinnersley-Chitre solution
Stationary axisymmetric systems of two extreme Kerr sources separated by a
massless strut, which arise as subfamilies of the well-known Kinnersley-Chitre
solution, are studied. We present explicit analytical formulas for the
individual masses and angular momenta of the constituents and establish the
range of the parameters for which such systems can be regarded as describing
black holes. The mass-angular momentum relations and the interaction force in
the black-hole configurations are also analyzed. Furthermore, we construct a
charging generalization of the Kinnersley-Chitre metric and, as applications of
the general formulas obtained, discuss two special cases describing a pair of
identical co- and counterrotating extreme Kerr-Newman black holes kept apart by
a conical singularity. From our analysis it follows in particular that the
equality relating the mass, angular momentum per unit mass and
electric charge of a single Kerr-Newman extreme black hole is no longer
verified by the analogous extreme black-hole constituents in binary
configurations.Comment: final version revised according to referee's suggestion
Instability of Amorphous Ru-Si-O Thin Films under Thermal Oxidation
Ternary films about 200 nm thick of composition Ru20Si15O65 have been synthesized by reactive rf magnetron sputtering of a Ru1Si1 target in an argon-oxygen gas. As-deposited, the films are X-ray-amorphous. Their atomic density is 8.9 × 10^22/cm^3 (5.1 g/cm^3), and their electrical resistivity is in the range of 2 mOmega cm. After annealing in dry oxygen at 600°C for 30 min, micron-sized grains of RuO2 grow out of the film and volatile RuO4 escapes. The significance of these results is discussed
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