arXiv subjects
Publications and source records attributed to T. S. Biro.
Hadron multiplicities are calculated in the ALCOR model for the Pb+Pb collisions at CERN SPS energy. Considering the newest experimental results, we display our prediction obtained from the ALCOR model for stable hadrons including strange baryons and anti-baryons.
We introduce the Transchemistry Model as a dynamical extension of the Algebraic Coalescence Rehadronization (ALCOR) model in describing the hadronization of quark matter which is expected to be produced in relativistic heavy ion collisions. Results are presented for CERN SPS NA49 Pb+Pb experiment calculating hadron multiplicities and momentum spectra. The freeze-out properties of different hadrons are characterized by similar temperature, density and flow profiles in cylindrically symmetric geometry.
The relativistic mean field model, the Zimányi - Moszkowski (ZM) Lagrangian describes nuclear matter and stable finite nuclei even in the non-relativistic limit. It fails, however, to predict the correct non-relativistic spin-orbit (SO) coupling. In this paper we improve on this matter by an additional tensor coupling analogous to the anomalous gyromagnetic ratio. It can be adjusted to describe the SO-term without changing the mean field solution of the ZM-Lagrangian for nuclear matter.
The damping rate of a Higgs field at zero momentum is calculated using the Braaten-Pisarski method and compared to the Lyapunov exponent of the classical SU(2) Yang-Mills Higgs system.
It is unlikely to reach at high temperatures the state which is used as the starting point of DCC formation in the quenched approximation. The chiral symmetry is restored in the linear sigma model by Goldstone modes (pions), because such isospin-p-wave states carry more entropy. In this paper we estimate this effect of isospin-angular motion in the mean field approximation assuming equipartition of the energy.
A dynamical model of confinement based on a transport theoretical description of the Friedberg-Lee model is extended to explicit color degrees of freedom. The string tension is reproduced by an adiabatic string formation from the nucleon ground state. Color isovector oscillation modes of a $q\bar{q}$-system are investigated for a wide range of relative $q\bar{q}$-momenta and the dynamical impact of color confinement on the quark motion is shown.
We have found in numerical simulations that the chaoticity of the classical hamiltonian lattice SU(2) gauge theory is reduced in the presence of static charges at the same total energy. The transition from strongly to weakly chaotic behavior is rather sudden at a critical charge strength.
We argue on a basis of a simple few mode model of SU(2) Yang-Mills theory that the color off-diagonal coupling of the soft plasmon to hard thermal excitations of the gauge field drives the collective plasma oscillations into chaotic motion despite the presence of the plasmon mass.
Hadron multiplicities --- especially for strange particles --- are calculated in the framework of the algebraic coalescence rehadronization model (ALCOR), which counts for redistribution of quarks into hadrons for relativistic heavy-ion collisions. The influence of Bjorken flow on the final hadronic composition are incorporated in the model. A comparison is made with the CERN SPS NA35 $S+S$ and $p+p$ experiments. The analysis of these experiments with ALCOR shows a strangeness enhancement for S+S collisions and a possible formation of a sort of semi-deconfined state of the matter. Predictions for Pb+Pb collisions (NA49) are also presented.
We explain why the maximal positive Lyapunov exponent of classical SU($N$) gauge theory coincides with (twice) the damping rate of a plasmon at rest in the leading order of thermal gauge theory. [This is a substantially revised and expanded version of the manuscript.]
On the basis of the Friedberg-Lee model we formulate a semiclassical transport theory to describe the phase-space evolution of nucleon-nucleon collisions on the quark level. The time evolution is given by a Vlasov-equation for the quark phase-space distribution and a Klein-Gordon equation for the mean-field describing the nucleon as a soliton bag. The Vlasov equation is solved numerically using an extended testparticle method. We test the confinement mechanism and mean-field effects in 1+1 dimensional simulations.
We speculate about a heavy bottom-charm six-quark baryon. A semiclassical and a gaussian estimate reveal that the octet-octet bbb-ccc configuration can be energetically favored with respect to the singlet-singlet one. This result suggests that a confined bbb-ccc six-quark state may exist. Such objects may be produced in appreciable amount in heavy ion collisions at LHC energies.
Applying a variational method to a Gaussian wave ansatz, we have derived a set of semi-classical evolution equations for SU(2) lattice gauge fields, which take the classical form in the limit of a vanishing width of the Gaussian wave packet. These equations are used to study the quantum effects on the classical evolutions of the lattice gauge fields.
We investigate the processes leading to phase-space equilibration of parton distributions in nuclear interactions at collider energies. We derive a set of rate equations describing the chemical equilibration of gluons and quarks including medium effects on the relevant QCD transport coefficients, and discuss their consequences for parton equilibration in heavy ion collisions.
We develop a semiclassical method to calculate the density of magnetic monopoles in non-abelian gauge theories at finite temperature in the dilute gas approximation. This quantity is related to the inverse magnetic screening length for which we obtain $μ_M = 0.255 g^2T$ in SU(2).