200 research outputs found
Towards azimuthal anisotropy of direct photons
Intensive radiation of magnetic bremsstrahlung type (synchrotron radiation)
resulting from the interaction of escaping quarks with the collective confining
colour field is discussed as a new possible mechanism of observed direct photon
anisotropy.Comment: 3 pages, Comments and references added, accepted to JETP Letters
(Pis'ma v ZhETF
CABARET in the ocean gyres
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Ocean Modelling 30 (2009): 155-168, doi:10.1016/j.ocemod.2009.06.009.A new high-resolution Eulerian numerical method is proposed for modelling quasigeostrophic ocean
dynamics in eddying regimes. The method is based on a novel, second-order non-dissipative and lowdispersive
conservative advection scheme called CABARET. The properties of the new method are
compared with those of several high-resolution Eulerian methods for linear advection and gas
dynamics. Then, the CABARET method is applied to the classical model of the double-gyre ocean
circulation and its performance is contrasted against that of the common vorticity-preserving Arakawa
method. In turbulent regimes, the new method permits credible numerical simulations on much coarser
computational grids.Supports from the Royal Society of London and from the Mary Sears Visitor Grant are
acknowledged by SK with gratitude. The work of VG was supported by the Russian Foundation for
Basic Research (RFBR), grant 06-01-00819a. Funding for PB was provided by the NSF grant 0725796
Probing confinement by direct photons and dileptons
The intensive synchrotron radiation resulting from quarks interacting with
the collective confining color field in relativistic heavy ion collisions is
discussed. The spectrum of photons with large transverse momentum is calculated
and compared with the experimental data to demonstrate the feasibility of this
type of radiation. A study of the earlier predicted azimuthal anisotropy in the
angular distribution of dileptons with respect to the three-momentum of the
pair is performed as well. This boundary-induced mechanism of lepton pair
production is shown to possess the features that are distinctly different from
the standard mechanisms and can potentially provide an efficient probe of
quark-gluon plasma formation.Comment: 7 pages, 3 figures, Fig., Refs. and explanations added, typos
corrected, text revise
Comments on quasiparticle models of quark-gluon plasma
Here we comment on the thermodynamic inconsistency problem and the
reformulation of statistical mechanics of widely studied quasiparticle models
of quark-gluon plasma. Their starting relation, the expression for pressure
itself is a wrong choice and lead to thermodynamic inconsistency and the
requirements of the reformulation of statistical mechanics. Hence we revise the
model using the standard statistical mechanics and is thermodynamically
consistent. We also show that the other quasiparticle models may be obtained
from our general formalism as a special case under certain restrictive
condition. Further, as an example, we applied our model to explain the nonideal
behaviour of gluon plasma and obtained a remarkable good fit to the lattice
results by adjusting just a single parameter.Comment: 7 pages, 2 figure, article (revised
Small-angle approximation in the description of radiative collective effects within an ultrarelativistic electron bunch
The problem of the evaluation of radiative collective effects accompanying accelerated motion of a short ultrarelativistic electron bunch in vacuum is considered within the framework of the small-angle approximation; second order expansion in the transverse velocity of electrons is performed in order to obtain an analytical expression for energy spread within the bunch. Comparison with earlier results by other authors shows good agreement
Strange quark matter: mapping QCD lattice results to finite baryon density by a quasi-particle model
A quasi-particle model is presented which describes QCD lattice results for
the 0, 2 and 4 quark-flavor equation of state. The results are mapped to finite
baryo-chemical potentials. As an application of the model we make a prediction
of deconfined matter with appropriate inclusion of strange quarks and consider
pure quark stars.Comment: invited talk at Strangeness 2000, Berkeley; prepared version for the
proceedings, 5 page
A new regime of anomalous penetration of relativistically strong laser radiation into an overdense plasma
It is shown that penetration of relativistically intense laser light into an
overdense plasma, accessible by self-induced transparency, occurs over a finite
length only. The penetration length depends crucially on the overdense plasma
parameter and increases with increasing incident intensity after exceeding the
threshold for self-induced transparency. Exact analytical solutions describing
the plasma-field distributions are presented.Comment: 6 pages, 2 figures in 2 separate eps files; submitted to JETP Letter
Gluon Quasiparticles and the Polyakov Loop
A synthesis of Polyakov loop models of the deconfinement transition and
quasiparticle models of gluon plasma thermodynamics leads to a class of models
in which gluon quasiparticles move in a non-trivial Polyakov loop background.
These models are successful candidates for explaining both critical behavior
and the equation of state for the SU(3) gauge theory at temperatures above the
deconfinement temperature T_c. Polyakov loops effects are most important at
intermediate temperatures from T_c up to roughly 2.5 T_c, while quasiparticle
mass effects provide the dominant correction to blackbody behavior at higher
temperatures.Comment: 6 pages, 7 eps figures, revtex
- …