4,863 research outputs found
Testing the Space-Time Structure of Event Generators
We report on work done in collaboration with Klaus Kinder-Geiger and John
Ellis which aims at connecting the space-time structure of event generator
simulations with observable output.Comment: 16 pages LaTeX, including 5 postscript figures. To appear in the
Proceedings of ``RHIC Physics and Beyond - Kay Kay Gee Day'' (Brookhaven
National Laboratory, 23 Oct 1998), ed. by B. Muller and R.D. Pisarski, AIP
Conference Proceeding
Equation of State and Collective Dynamics
This talk summarizes the present status of a program to quantitatively relate
data from the Relativistic Heavy Ion Collider (RHIC) on collective expansion
flow to the Equation of State (EOS) of hot and dense strongly interacting
matter, including the quark-gluon plasma and the quark-hadron phase transition.
The limits reached with the present state of the art and the next steps
required to make further progress will both be discussed.Comment: 8 pages, 6 two-part figures. Invited talk given at the 5th
International Conference on the Physics and Astrophysics of Quark-Gluon
Plasma (ICPAQGP 2005), Kolkata (India), Feb 8-12, 2005. Proceedings to be
published in Journal of Physics: Conference Series (Jan-E Alam et al., eds.
Thermal hadron production in pp and p{\bar p} collisions
It is shown that the hadron production in high energy pp and p{\bar p}
collisions, calculated by assuming that particles originate in hadron gas
fireballs at thermal and partial chemical equilibrium, agrees very well with
the data. The temperature of the hadron gas fireballs, determined by fitting
hadron abundances, does not seem to depend on the centre of mass energy, having
a nearly constant value of about 170 MeV. This value is in agreement with that
obtained in e^+e^- collisions and supports a universal hadronization mechanism
in all kinds of reactions consisting in a parton-hadron transition at critical
values of temperature and pressure.Comment: 41 pages, 11 .eps figures, published in Z. Phys. C Revision -
Corrections of two formulae in Sect.
Three-Point Spectral Density in QED and the Ward Identity at Finite Temperature
We derive the spectral representations of QED 3-point functions and then
explicitly calculate the 3-point spectral densities in hard thermal loop
approximation within the real time formalism. The Ward identities obeyed by the
retarded and advanced 2- and 3-point functions are discussed. We compare our
results with those for hot QCD .Comment: 16 pages, 1 figure, some corrections in sec1, sec.
Relativistic Quantum Transport Theory for Electrodynamics
We investigate the relationship between the covariant and the
three-dimensional (equal-time) formulations of quantum kinetic theory. We show
that the three-dimensional approach can be obtained as the energy average of
the covariant formulation. We illustrate this statement in scalar and spinor
QED. For scalar QED we derive Lorentz covariant transport and constraint
equations directly from the Klein-Gordon equation rather than through the
previously used Feshbach-Villars representation. We then consider pair
production in a spatially homogeneous but time-dependent electric field and
show that the pair density is derived much more easily via the energy averaging
method than in the equal-time representation. Proceeding to spinor QED, we
derive the covariant version of the equal-time equation derived by
Bialynicki-Birula et al. We show that it must be supplemented by another
self-adjoint equation to obtain a complete description of the covariant spinor
Wigner operator. After spinor decomposition and energy average we study the
classical limit of the resulting three-dimensional kinetic equations. There are
only two independent spinor components in this limit, the mass density and the
spin density, and we derive also their covariant equations of motion. We then
show that the equal-time kinetic equation provides a complete description only
for constant external electromagnetic fields, but is in general incomplete. It
must be supplemented by additional constraints which we derive explicitly from
the covariant formulation.Comment: 32 pages, no figures, standard Late
Three-Point Functions at Finite Temperature
We study 3-point functions at finite temperature in the closed time path
formalism. We give a general decomposition of the eight component tensor in
terms of seven vertex functions. We derive a spectral representation for these
seven functions in terms of two independent real spectral functions. We derive
relationships between the seven functions and obtain a representation of the
vertex tensor that greatly simplifies calculations in real time.Comment: 21 pages LaTeX; one ps-figure; Revised version, contains more
references and discussio
What can we learn from three-pion interferometry ?
We address the question which additional information on the source shape and
dynamics can be extracted from three-particle Bose-Einstein correlations. For
chaotic sources the true three-particle correlation term is shown to be
sensitive to the momentum dependence of the saddle point of the source and to
its asymmetries around that point. For partially coherent sources the
three-pion correlator allows to measure the degree of coherence without
contamination from resonance decays. We derive the most general Gaussian
parametrization of the two- and three-particle correlator for this case and
discuss the space-time interpretation of the corresponding parameters.Comment: 16 pages, to be published in Phys. Rev.
Bose-Einstein Final State Symmetrization for Event Generators of Heavy Ion Collisions
We discuss algorithms which allow to calculate identical two-particle
correlations from numerical simulations of relativistic heavy ion collisions. A
toy model is used to illustrate their properties.Comment: Talk given at CRIS'98 (Catania, June 8-12, 1998), to appear in
"CRIS'98: Measuring the size of things in the Universe: HBT interferometry
and heavy ion physics", (S. Costa et al., eds.), World Scientific, Singapore,
1998. (10 pages Latex, 1 eps-figure, extended version of conference
proceedings, Fig1 a,b added and corresponding discussion enlarged
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