191,130 research outputs found
Exploration of Resonant Continuum and Giant Resonance in the Relativistic Approach
Single-particle resonant-states in the continuum are determined by solving
scattering states of the Dirac equation with proper asymptotic conditions in
the relativistic mean field theory (RMF). The regular and irregular solutions
of the Dirac equation at a large radius where the nuclear potentials vanish are
relativistic Coulomb wave functions, which are calculated numerically.
Energies, widths and wave functions of single-particle resonance states in the
continuum for ^{120}Sn are studied in the RMF with the parameter set of NL3.
The isoscalar giant octupole resonance of ^{120}Sn is investigated in a fully
consistent relativistic random phase approximation. Comparing the results with
including full continuum states and only those single-particle resonances we
find that the contributions from those resonant-states dominate in the nuclear
giant resonant processes.Comment: 16 pages, 2 figure
Shifting with
Precision measurements at the resonance agree well with the standard
model. However, there is still a hint of a discrepancy, not so much in by
itself (which has received a great deal of attention in the past several years)
but in the forward-backward asymmetry together with . The two
are of course correlated. We explore the possibilty that these and other
effects are due to the mixing of and with one or more heavy quarks.Comment: 11 pages, 1 Figure, LaTex fil
Numerical framework for transcritical real-fluid reacting flow simulations using the flamelet progress variable approach
An extension to the classical FPV model is developed for transcritical
real-fluid combustion simulations in the context of finite volume, fully
compressible, explicit solvers. A double-flux model is developed for
transcritical flows to eliminate the spurious pressure oscillations. A hybrid
scheme with entropy-stable flux correction is formulated to robustly represent
large density ratios. The thermodynamics for ideal-gas values is modeled by a
linearized specific heat ratio model. Parameters needed for the cubic EoS are
pre-tabulated for the evaluation of departure functions and a quadratic
expression is used to recover the attraction parameter. The novelty of the
proposed approach lies in the ability to account for pressure and temperature
variations from the baseline table. Cryogenic LOX/GH2 mixing and reacting cases
are performed to demonstrate the capability of the proposed approach in
multidimensional simulations. The proposed combustion model and numerical
schemes are directly applicable for LES simulations of real applications under
transcritical conditions.Comment: 55th AIAA Aerospace Sciences Meeting, Dallas, T
A Study of Gluon Propagator on Coarse Lattice
We study gluon propagator in Landau gauge with lattice QCD, where we use an
improved lattice action. The calculation of gluon propagator is performed on
lattices with the lattice spacing from 0.40 fm to 0.24 fm and with the lattice
volume from to . We try to fit our results by two
different ways, in the first one we interpret the calculated gluon propagators
as a function of the continuum momentum, while in the second we interpret the
propagators as a function of the lattice momentum. In the both we use models
which are the same in continuum limit. A qualitative agreement between two
fittings is found.Comment: Revtex 14pages, 11 figure
Does Every Quasar Harbor A Blazar?
Assuming there is a blazar type continuum in every radio-loud quasar, we find
that the free-free heating due to the beamed infrared continuum can greatly
enhance collisionally excited lines, and thus explain the stronger CIV
1549 line emission observed in radio loud quasars. We further predict
that the CIV line should show variability {\it not} associated with observed
continuum or Ly variability.Comment: 15 pages, 3 figures; to appear in Astrophys. J. Let
Dissipate locally, couple globally: a sharp transition from decoupling to infinite range coupling in Josephson arrays with on-site dissipation
We study the T=0 normal to superconducting transition of Josephson arrays
with {\it on-site} dissipation. A perturbative renormalization group solution
is given. Like the previously studied case of {\it bond} dissipation (BD), this
is a "floating" to coupled (FC) phase transition. {\it Unlike} the BD
transition, at which {\it only} nearest-neighbor couplings become relevant,
here {\it all} inter-grain couplings, out to {\it infinitely} large distances,
do so simultaneously. We predict, for the first time in an FC transition, a
diverging spatial correlation length. Our results show the robustness of
floating phases in dissipative quantum systems.Comment: 7+ pages, 3 eps figures, Europhysics Letters preprint format, as
publishe
Decay of the Z Boson into Scalar Particles
In extensions of the standard model, light scalar particles are often
possible because of symmetry considerations. We study the decay of the Z boson
into such particles. In particular, we consider for illustration the scalar
sector of a recently proposed model of the 17-keV neutrino which satisfies all
laboratory, astrophysical, and cosmological constraints.Comment: 11 pages (2 figures, not included) (Revised, Oct 1992). Some
equations have been corrected and 1 figure has been eliminate
Dynamics of the Lyman alpha and C IV emitting gas in 3C 273
In this paper we study the variability properties of the Lyman alpha and C IV
emission lines in 3C273 using archival IUE observations. Our data show for the
first time the existence of variability on time scales of several years. We
study the spatial distribution and the velocity field of the emitting gas by
performing detailed analyses on the line variability using correlations, 1D and
2D response functions, and principal component analysis. In both lines we find
evidence for two components, one which has the dynamic properties of gas in
Keplerian motion around a black hole with a mass of the order of 10^9 Mo, and
one which is characterized by high, blue-shifted velocities at large lag. There
is no indication of the presence of optically thick emission medium neither in
the Lya, nor in the Civ response functions. The component characterized by
blue-shifted velocities, which is comparatively much stronger in Civ than in
Lya, is more or less compatible with being the result of gas falling towards
the central black hole with free-fall acceleration. We propose however that the
line emission at high, blue-shifted velocities is better explained in terms of
entrainment of gas clouds by the jet. This gas is therefore probably
collisionally excited as a result of heating due to the intense infrared
radiation from the jet, which would explain the strength of this component in
Civ relative to Lya. This phenomenon might be a signature of disk-jet
interaction.Comment: 16 pages, 10 figures. Accepted for publication in ApJ. Uses aaste
Energy scale independence of Koide's relation for quark and lepton masses
Koide's mass relation of charged leptons has been extended to quarks and
neutrinos, and we prove here that this relation is independent of energy scale
in a huge energy range from to . By using the
parameters , and to describe the deviations of quarks and
neutrinos from the exact Koide's relation, we also check the quark-lepton
complementarity of masses such as , and show that it is also independent (or insensitive) of energy scale.Comment: 16 Latex pages, 2 figures, final version to appear in PR
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