14,885 research outputs found
Anomalous diffusion of pions at RHIC
After pointing out the difference between normal and anomalous diffusion, we
consider a hadron resonance cascade (HRC) model simulation for particle
emission at RHIC and point out, that rescattering in an expanding hadron
resonance gas leads to a heavy tail in the source distribution. The results are
compared to recent PHENIX measurements of the tail of the particle emitting
source in Au+Au collisions at RHIC. In this context, we show, how can one
distinguish experimentally the anomalous diffusion of hadrons from a second
order QCD phase transition.Comment: 12 pages, 26 figures. Presented by T. Csorgo at the 2nd Workshop on
Particle Femtoscopy and Correlations - WPCF in Sao Paulo, sept 2006.
Brazilian Journal of Physics in press, minor misprints fixe
Simple solutions of fireball hydrodynamics for rotating and expanding triaxial ellipsoids and final state observables
We present a class of analytic solutions of non-relativistic fireball
hydrodynamics for a fairly general class of equation of state. The presented
solution describes the expansion of a triaxial ellipsoid that rotates around
one of the principal axes. We calculate the hadronic final state observables
such as single-particle spectra, directed, elliptic and third flows, as well as
HBT correlations and corresponding radius parameters, utilizing simple analytic
formulas. We call attention to the fact that the final tilt angle of the
fireball, an important observable quantity, is not independent on the exact
definition of it: one gets different angles from the single-particle spectra
and from HBT measurements. Taken together, it is pointed out that these
observables may be sufficient for the determination of the magnitude of the
rotation of the fireball. We argue that observing this rotation and its
dependence on collision energy would reveal the softness of the equation of
state. Thus determining the rotation may be a powerful tool for the
experimental search for the critical point in the phase diagram of strongly
interacting matter.Comment: 17 pages, 12 figure panel
A new family of exact and rotating solutions of fireball hydrodynamics
A new class of analytic, exact, rotating, self-similar and surprisingly
simple solutions of non-relativistic hydrodynamics are presented for a
three-dimensionally expanding, spheroidally symmetric fireball. These results
generalize earlier, non-rotating solutions for ellipsoidally symmetric
fireballs with directional, three-dimensional Hubble flows. The solutions are
presented for a general class of equations of state that includes the lattice
QCD equations of state and may feature inhomogeneous temperature and
corresponding density profiles.Comment: Dedicated to T. Kodama on the occasion of his 70th birthday. 15
pages, no figures. Accepted for publication at Phys. Rev. C. Minor rewritings
from previous versio
A New Family of Simple Solutions of Perfect Fluid Hydrodynamics
A new class of accelerating, exact and explicit solutions of relativistic
hydrodynamics is found - more than 50 years after the previous similar result,
the Landau-Khalatnikov solution. Surprisingly, the new solutions have a simple
form, that generalizes the renowned, but accelerationless, Hwa-Bjorken
solution. These new solutions take into account the work done by the fluid
elements on each other, and work not only in one temporal and one spatial
dimensions, but also in arbitrary number of spatial dimensions. They are
applied here for an advanced estimation of initial energy density and life-time
of the reaction in ultra-relativistic heavy ion collisions.Comment: 10 pages, 5 figures. EOS is generalized to include a bag constant,
clarity of the presentation is improved and a misprinted label is corrected
in Fig. 2.
Similar final states from different initial states using new exact solutions of relativistic hydrodynamics
We present exact, analytic and simple solutions of relativistic perfect fluid
hydrodynamics. The solutions allow us to calculate the rapidity distribution of
the particles produced at the freeze-out, and fit them to the measured rapidity
distribution data. We also give an advanced estimation of the energy density
reached in heavy ion collisions, and an improved estimation of the life-time of
the reaction.Comment: This article is a written-up version of the talk given by M. Csanad
on the Zimanyi '75 Memorial Workshop held in Budapest, June 200
Accelerating Solutions of Perfect Fluid Hydrodynamics for Initial Energy Density and Life-Time Measurements in Heavy Ion Collisions
A new class of accelerating, exact, explicit and simple solutions of
relativistic hydrodynamics is presented. Since these new solutions yield a
finite rapidity distribution, they lead to an advanced estimate of the initial
energy density and life-time of high energy heavy ion reactions. Accelerating
solutions are also given for spherical expansions in arbitrary number of
spatial dimensions.Comment: 3 pages, labels in Fig.2b corrected. Based on T. Csorgo's talk at the
XXXVIth Int. Symp. Multiparticle Dynamics (ISMD 2006), Paraty, RJ, Brazil.
Submitted to the Brazilian Journal of Physic
Ordering variable for parton showers
The parton splittings in a parton shower are ordered according to an ordering
variable, for example the transverse momentum of the daughter partons relative
to the direction of the mother, the virtuality of the splitting, or the angle
between the daughter partons. We analyze the choice of the ordering variable
and conclude that one particular choice has the advantage of factoring softer
splittings from harder splittings graph by graph in a physical gauge.Comment: 28 pages, 5 figure
From Quark Gluon Plasma to a Perfect Fluid of Quarks and Beyond
With high energy heavy ion collisions one tries to create a new forms of
matter that is similar to the one present at the birth of our Universe. Recent
development on flow pattern, initial energy-density and freeze-out temperature
shows that most likely this new form of matter is in a deconfined state, has
colored degrees of freedom and is more fluid-like than gas-like. In present
paper we calculate estimations on the physical properties of this new-old
matter.Comment: 10 pages, 5 figures, to appear in the proceedings of the 44th
International School of Subnuclear Physics, Erice, Sicily, 29 August - 7
September 200
Precursors of an upcoming solar cycle at high latitudes from coronal green line data
After reviewing potential early indicators of an upcoming solar cycle at high
latitudes, we focus attention on the rush-to-the-poles (RTTP) phenomenon in
coronal green line emission. Considering various correlations between
properties of the RTTP with the upcoming solar cycle we find a correlation
between the rate of the RTTP and the time delay until the maximum of the next
solar cycle. On the basis of this correlation and the known internal
regularities of the sunspot number series we predict that, following a minimum
in 2019, cycle 25 will peak in late 2024 at an amplitude of about 130 (in terms
of smoothed monthly revised sunspot numbers). This slightly exceeds the
amplitude of cycle 24 but it would still make cycle 25 a fairly weak cycle.Comment: 17 pages, 5 figures J. Atm. Sol.-Terr. Phys., in pres
Hydrocarbons in the banana leaf, Musa sapientum
Mass spectrometry, spectroscopy, and thin layer and gas chromatography studies of hydrocarbons in banana leave
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