20 research outputs found
Lambda Polarization in an Exact Rotating and Expanding fluid dynamical model for peripheral heavy ion reactions
We calculate the Lambda polarization in an exact analytical, rotating model
based on parameters extracted from a high resolution (3+1)D Particle-in-Cell
Relativistic hydrodynamics calculation. The polarization is attributed to
effects from thermal vorticity and for the first time the effects of the radial
and axial acceleration are also studied separatel
Pion Mass Shift and the Kinetic Freeze Out Process
The kinetic Freeze Out process of a pion gas through a finite layer with
time-like normal is considered. The pion gas is described by a Boltzmann gas
with elastic collisions among the pions. Within this model, the impact of the
in-medium pion mass modification on the Freeze Out process is studied. A
marginal change of the Freeze Out variables temperature and flow velocity and
an insignificant modification of the frozen out particle distribution function
has been found.Comment: European Physical Journal A (2009), in pres
Fluctuations in Hadronizing QGP
The dynamical development of the cooling and hadronizing quark-gluon Plasma
(QGP) is studied in a simple model assuming critical fluctuations in the QGP to
Hadronic Matter (HM) and a first order transition in a small finite system. We
consider an earlier determined free-energy density curve in the neighbourhood
of the critical point, with two local minima corresponding to the equilibrium
hadronic and QGP configurations. In this approach the divergence at e = 0
eliminates fluctuations with negative or zero energy. The barrier between the
equilibrium states is obtained from an estimated value of the surface tension
between the two phases. We obtain a characteristic behavior for the skewness
and the kurtosis of energy density fluctuations, which can be studied via a
beam energy scan program.Comment: 5 pages, 5 figure
Freeze Out Process with In-Medium Nucleon Mass
We investigate the kinetic freeze out scenario of a nucleon gas through a
finite layer. The in-medium mass modification of nucleons and it's impact on
the freeze out process is studied. A considerable modification of the
thermodynamical parameters temperature, flow-velocity, energy density and
particle density has been found in comparison with evaluations which use a
constant vacuum nucleon mass.Comment: 6 pages, 4 figures, Proceeding of the Conference "Quark Matter 2005",
4th - 9th August 2005, Budapest/Hungar
Higher moment singularities explored by the net proton non-statistical fluctuations
We use the non-statistical fluctuation instead of the full one to explore the
higher moment singularities of net proton event distributions in the
relativistic Au+Au collisions at from 11.5 to 200 GeV
calculated by the parton and hadron cascade model PACIAE. The PACIAE results of
mean (), variance (), skewness (), and kurtosis () are
consistent with the corresponding STAR data. Non-statistical moments are
calculated as the difference between the moments derived from real events and
the ones from mixed events, which are constructed by combining particles
randomly selected from different real events. An evidence of singularity at
60 GeV is first seen in the energy dependent
non-statistical and .Comment: 5 pages,5 figure
Correlations among elliptic flow parameter, impact parameter, and multiplicity
The elliptic flow parameter, v2, in the Fourier expansion of the event-by-event charged-particle multiplicity azimuthal distribution in the momentum space is studied by taking into account the multiplicity fluctuations. The correlations among measurable variables of v2, charged multiplicity, and impact parameter are investigated using a multiple phase transport model with string melting. It turned out that the charged multiplicity and impact parameter are negatively correlated. This correlation results in the peak structure in v2 as a function of the participant nucleon number (charged multiplicity, impact parameter) measured in RHIC experiments. It is suggested that v2 calculated in the event-wise average is about 20% larger than in the particle-wise average, so event-wise average should be used in the theoretical calculations.publishedVersio