120 research outputs found
Multi Module Model for Ultra-Relativistic Heavy Ion Collisions
The Multi Module Model for Ultra-Relativistic Heavy Ion Collisions at RHIC
and LHC energies is presented. It uses the Effective String Rope Model for the
calculation of the initial stages of the reaction; the output of this model is
used as the initial state for the subsequent one-fluid calculations. It is
shown that such an initial state leads to the creation of the third flow
component. The hydrodynamical evolution of the energy density distribution is
also presented.Comment: Talk given at the New Trend in High-Energy Physics, Yalta, Crimea,
Ukraine, September 22-29, 2001. To be published in the Proceedings. 8 pages,
2 figures The Fig. 2 has been update
The source of elliptic flow and initial conditions for hydrodynamical calculations
A model for energy, pressure and flow velocity distributions at the beginning
of relativistic heavy ion collisions is presented, which can be used as initial
condition for hydrodynamical calculations. The results show that QGP forms a
tilted disk, such that the direction of the largest pressure gradient stays in
the reaction plane, but deviates from both the beam and the usual transverse
flow directions. Such initial condition may lead to the creation of "antiflow"
or "third flow component".Comment: Talk given at the New Trends in High-Energy Physics, Yalta (Crimea),
Ukraine, May 27 - June 4, 2000. 8 pages, 2 figures. The misprint t_0 instead
of x_0 has been corrected in several place
Covariant description of kinetic freeze out through a finite time-like layer
The Freeze Out (FO) problem is addressed for a covariant FO probability and a
finite FO layer with a time-like normal vector continuing the line of studies
introduced in Ref. [1]. The resulting post FO momentum distribution functions
are presented and discussed. We show that in general the post FO distributions
are non-thermal and asymmetric distributions even for time-like FO situations.Comment: 10 pages, 12 figures, major rewrite with changed content, corrected
typos and new references adde
Dual-Regge Approach to High-Energy, Low-Mass Diffraction Dissociation
A dual-Regge model with a nonlinear proton Regge trajectory in the missing
mass channel, describing the experimental data on low-mass single diffraction
dissociation, is constructed. Predictions for the LHC energies are given.Comment: 14 pages, 12 figure
Effective String Rope Model for the initial stages of Ultra-Relativistic Heavy Ion Collisions
Different approaches to describe initial stages of relativistic heavy ion
collisions are discussed qualitatively and quantitatively. An Effective String
Rope Model is presented for heavy ion collisions at RHIC energies. Our model
takes into account baryon recoil for both target and projectile, arising from
the acceleration of partons in an effective field, produced in the collision.
The typical field strength (string tension) for RHIC energies is about 5-12
GeV/fm, what allows us to talk about ``string ropes''. The results show that a
QGP forms a tilted disk, such that the direction of the largest pressure
gradient stays in the reaction plane, but deviates from both the beam and the
usual transverse flow directions. The produced initial state can be used as an
initial condition for further hydrodynamical calculations. Such initial
conditions lead to the creation of third flow component.Comment: 47 pages, 14 figures. Minor changes were made, style was changed to
"elsart". Paper is accepted to Nucl. Phys.
Covariant description of kinetic freeze out through a finite space-like layer
The problem of Freeze Out (FO) in relativistic heavy ion reactions is
addressed. We develop and analyze an idealized one-dimensional model of FO in a
finite layer, based on the covariant FO probability. The resulting post FO
phase-space distributions are discussed for different FO probabilities and
layer thicknesses.Comment: 16 pages, 19 figures, changed content, references adde
The 3rd Flow Component as a QGP Signal
Earlier fluid dynamical calculations with QGP show a softening of the
directed flow while with hadronic matter this effect is absent. On the other
hand, we indicated that a third flow component shows up in the reaction plane
as an enhanced emission, which is orthogonal to the directed flow. This is not
shadowed by the deflected projectile and target, and shows up at measurable
rapidities, . To study the formation of this effect initial stages
of relativistic heavy ion collisions are studied. An effective string rope
model is presented for heavy ion collisions at RHIC energies. Our model takes
into account baryon recoil for both target and projectile, arising from the
acceleration of partons in an effective field. The typical field strength
(string tension) for RHIC energies is about 5-12 GeV/fm, what allows us to talk
about "string ropes". The results show that QGP forms a tilted disk, such that
the direction of the largest pressure gradient stays in the reaction plane, but
deviates from both the beam and the usual transverse flow directions. The
produced initial state can be used as an initial condition for further
hydrodynamical calculations. Such initial conditions lead to the creation of
third flow component. Recent measurements are promising that this effect
can be used as a diagnostic tool of the QGP
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