121066263
Space-time picture of high-energy heavy-ion collisions and scaling properties of proton spectra
Abstract A comparative analysis of predictions of three typical models of relativistic nucleus-nucleus collisions is performed. It includes the model of partial transparency, the hydrodynamical model and the intranuclear cascade model. The results of proton and pion spectra calculations are compared with the experimental data available at incident energies of 0.8, 2.1 and 3.6 GeV nucleon . The effects of deviation from thermodynamical equilibrium due to mutual transparency of projectile and target nuclei are studied. The importance of the transition layer arising on the boundary of the overlapping parts of interacting nuclei has been demonstrated. The emission from this layer gives the main contribution to inclusive proton spectra in the target fragmentation region. In this region all the three models are in good agreement with experiment and, in particular, reproduce the scaling properties of proton inclusive cross sections satisfactorily. Considerable difference in the models' predictions takes place in the central rapidity region, especially in central collisions of identical nuclei. Experiments are suggested to study the mechanisms of the transition layer formation and the nature of scaling behaviour of proton spectra.
115321070
On the relationship between Boltzmann-Langevin and Boltzmann-Uehling-Uhlenbeck models
118142337
Partial-transparency effects in high-energy collisions of heavy ions
A model is proposed for heavy-ion collisions at E/sub lab/approx.1 GeV/nucleon for the case of an incomplete statistical equilibrium in the highly excited nuclear matter. This approach can reproduce the characteristic double-humped structure of the experimental rapidity distributions of secondary particles.
14791019
Lattice QCD constraints on hybrid and quark stars
A QCD-motivated dynamical-quasiparticle model with parameters adjusted to reproduce the lattice-QCD equation of state is extrapolated from the region of high temperatures and moderate baryonic densities to the domain of high baryonic densities and zero temperature. The resulting equation of state matched with realistic hadronic equations of state predicts a phase transition into the quark phase at higher densities than those reachable in neutron star interiors. This excludes the possibility of the existence of hybrid (hadron-quark) stars. Pure quark stars are possible and have low masses, small radii, and very high central densities. Similar results are obtained for a simple bag model with massive quarks, fitted to reproduce the same lattice results. Self-bound quark matter is also excluded within these models. Uncertainties in the present extrapolation are discussed. Comparison with standard bag models is made.
18368050
Equation of State of Strongly Coupled Quark–Gluon Plasma – Path Integral Monte Carlo Results
A strongly coupled plasma of quark and gluon quasiparticles at temperatures from 1.1Tc to 3Tc is studied by path integral Monte Carlo simulations. This method extends previous classical nonrelativistic simulations based on a color Coulomb interaction to the quantum regime. We present the equation of state and find good agreement with lattice results. Further, pair distribution functions and color correlation functions are computed indicating strong correlations and liquid-like behavior (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
119351822
Equation of state of deconfined matter within a dynamical quasiparticle description
A simple quasiparticle model, motivated by lowest-order perturbative QCD, is proposed. It is applied to interpret the lattice QCD equation of state. A reasonable reproduction of the lattice data is obtained. In contrast to existing quasiparticle models, the present model is formulated in dynamical rather than thermodynamical terms, and is easily applicable to a system with finite baryon density. In particular, the model simulates the confinement property.
12114990
Pion Observables in the Extended NJL Model with Vector and Axial-Vector Mesons☆
Abstract The momentum-space bosonization method of a Nambu and Jona-Lasinio type model with vector and axial-vector mesons is applied to ππ scattering. Unlike the case in earlier published papers, we obtain the ππ scattering amplitude using the linear and nonlinear realizations of chiral symmetry and fully taking into account the momentum dependence of meson vertices. We show the full physical equivalence between these two approaches. The chiral expansion procedure in this model is discussed in detail. Chiral expansions of the quark mass, pion mass and constant f π are obtained. The low-energy ππ phase shifts are compared to the available data. We also study the scalar form factor of the pion.
119426627
Prompt contributions to the dilepton yield in heavy ion collisions

Abstract: The mass spectrum is calculated for those dileptons which are produced in the early phase of a heavy ion collisions via the direct production NN → l+l−X and via the Compton process GN → l+l−X with prompt gluons radiated in preceding NN interactions. Both mechanisms produce a mass spectrum which decreases steeply with invariant mass of the l+l− pair and which is below the CERES data for Pb-Au collisions by about one order of magnitude.
896237
Electroproduction of charmonia off nuclei
In a recent publication we have calculated elastic charmonium production in ep collisions employing realistic charmonia wave functions and dipole cross sections and have found good agreement with the data in a wide range of s and Q^2. Using the ingredients from those calculations we calculate exclusive electroproduction of charmonia off nuclei. Here new effects become important, (i) color filtering of the c-cbar pair on its trajectory through nuclear matter, (ii) dependence on the finite lifetime of the c-cbar fluctuation (coherence length) and (iii) gluon shadowing in a nucleus compared to the one in a nucleon. Total coherent and incoherent cross sections for C, Cu and Pb as functions of s and Q^2 are presented together with some differential cross sections. The results can be tested with future electron-nucleus colliders or in peripheral collisions of ultrarelativistic heavy ions.
182081169
PHOTON PROPAGATOR ASYMPTOTICS AT Q**2 ---> infinity IN THE SOURCE THEORY
126455257
A1 MESON IN THE DECAY tau ---> tau-neutrino 3 pi