1,922 research outputs found
Nuclear and Quark Matter at High Temperature
We review important ideas on nuclear and quark matter description on the
basis of high- temperature field theory concepts, like resummation, dimensional
reduction, interaction scale separation and spectral function modification in
media. Statistical and thermodynamical concepts are spotted in the light of
these methods concentrating on the - partially still open - problems of the
hadronization process.Comment: Review intended for EPJ A Topical Issu
Thermalization of gluons at RHIC including gg <-> ggg interactions in a parton cascade
Employing a newly developed pQCD inspired parton cascade we simulate the
space time evolution of gluons which are produced initially in a heavy ion
collision at RHIC energy. The inelastic interactions
are for the first time implemented obeying full detailed balance. The numerical
results show that thermalization of gluons is mainly driven by the inelastic
gluonic interactions and reaches equilibrium at fm/c. In simulations
for noncentral collisions considerable partonic elliptic flow is
generated being comparable with the experimental data.Comment: 4 pages, 3 figures; Contribution to proceedings of Quark Matter 2005,
Budapest, Hungary, Aug 4-9 200
Transcriptional and functional analysis of the gene for factor C, an extracellular signal protein involved in cytodifferentiation of Streptomyces griseus
Metals in Catalysis, Biomimetics & Inorganic Material
Equation of state and initial temperature of quark gluon plasma at RHIC
In gold-gold collisions of the Relativistic Heavy Ion Collider (RHIC) a
perfect fluid of quarks, sometimes called the strongly interacting quark gluon
plasma (sQGP) is created for an extremely short time. The time evolution of
this fluid can be described by hydrodynamical models. After expansion and
cooling, the freeze-out happens and hadrons are created. Their distribution
reveals information about the final state of the fluid. To investigate the time
evolution one needs to analyze penetrating probes, such as direct photon
observables. Transverse momentum distributions of low energy direct photons
were mesured in 2010 by PHENIX, while azimuthal asymmetry in 2011. These
measurements can be compared to hydrodynamics to determine the equation of
state and the initial temperature of sQGP. In this paper we analyze an 1+3
dimensional solution of relativistic hydrodynamics. We calculate momentum
distribution, azimuthal asymmetry and momentum correlations of direct photons.
Based on earlier fits to hadronic spectra, we compare photon calculations to
measurements to determine the equation of state and the initial temperature of
sQGP. We find that the initial temperature in the center of the fireball is
507+-12 MeV, while for the sound speed we get a speed of sound of 0.36+-0.02.
We also estimate a systematic error of these results. We find that the measured
azimuthal asymmetry is also not incompatible with this model, and predict a
photon source that is significantly larger in the out direction than in the
side direction.Comment: 12 pages, 4 figures. This work was supported by the OTKA grant
NK-73143 and NK-101438 and M. Csanad's Bolyai scholarshi
Nuclear mitochondrial DNA sequences in the rabbit genome
Numtogenesis is observable in the mammalian genomes resulting in the integration of mitochondrial segments into the nuclear genomes (numts). To identify numts in rabbit, we aligned mitochondrial and nuclear genomes. Alignment significance threshold was calculated and individual characteristics of numts were analysed. We found 153 numts in the nuclear genome. The GC content of numts were significantly lower than the GC content of their genomic flanking regions or the genome itself. The frequency of three mammalian-wide interspersed repeats were increased in the proximity of numts. The decreased GC content around numts strengthen the theory which supposes a link between DNA structural instability and numt integration
Energy loss in perturbative QCD
We review the properties of energetic parton propagation in hot or cold QCD
matter, as obtained in recent works. Advances in understanding the energy loss
- collisional and radiative - are summarized, with emphasis on the latter: it
features very interesting properties which may help to detect the quark-gluon
plasma produced in heavy ion collisions. We describe two different theoretical
approaches, which lead to the same radiated gluon energy spectrum. The case of
a longitudinally expanding QCD plasma is investigated. The energy lost by a jet
with given opening angle is calculated in view of making predictions for the
suppression (quenching) of hard jet production. Phenomenological implications
for the difference between hot and cold matter are discussed. Numerical
estimates of the loss suggest that it may be significantly enhanced in hot
compared to cold matter.Comment: 49 pages latex file with 11 embedded PS figures. Uses ar.sty
(included), one equation revised. submitted to Annual Review of Nuclear and
Particle Scienc
DCC dynamics with the SU(3) linear sigma model
The SU(3) extension of the linear sigma model is employed to elucidate the
effect of including strangeness on the formation of disoriented chiral
condensates. By means of a Hartree factorization, approximate dispersion
relations for the 18 scalar and pseudoscalar meson species are derived and
their self-consistent solution makes it possible to trace out the thermal path
of the two order parameters as well as delineate the region of instability
within which spontaneous pair creation becomes possible. The results depend
significantly on the employed sigma mass, with the highest values yielding the
largest regions of instability. An approximate solution of the equations of
motion for the order parameter in scenarios emulating uniform scaling
expansions show that even with a rapid quench only the pionic modes grow
unstable. Nevertheless, the rapid and oscillatory relaxation of the order
parameters leads to enhanced production of both pions and (to a lesser degree)
kaons.Comment: 29 pages, RevTeX, 11 postscript figures, discussion about anomaly
term adde
The System of Multi Color-flux-tubes in the Dual Ginzburg-Landau Theory
We study the system of multi color-flux-tubes in terms of the dual Ginzburg
-Landau theory. We consider two ideal cases, where the directions of all the
color-flux-tubes are the same in one case and alternative in the other case for
neighboring flux-tubes. We formulate the system of multi color-flux -tubes by
regarding it as the system of two color-flux-tubes penetrating through a two
dimensional sphere surface. We find the multi flux-tube configuration becomes
uniform above some critical flux-tube number density . On the other hand, the inhomogeneity on the color electric
distribution appears when the flux-tube density is smaller than . We
discuss the relation between the inhomogeneity in the color-electric
distribution and the flux-tube number density in the multi-flux-tube system
created during the QGP formation process in the ultra-relativistic heavy-ion
collision.Comment: 17 pages, Revtex, ( 7 figures - available on request from
[email protected]
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