123291698
Equilibration in intermediate-energy heavy-ion collisions within a relativistic mean-field two-fluid model
A two-fluid model with meanσ- andω-fields is formulated for the treatment of heavy-ion collisions at incident energies around 1 GeV/u. In this energy range Fermi and Bose statistics for baryons and pions, respectively, cannot be replaced by Boltzmann statistics. The collisional coupling between the two fluids is formulated in terms of the effective nucleon-nucleon cross-sections in nuclear medium taking Pauli blocking into account. For two counterstreaming nuclear fluids the comparison of results obtained from our relativistic mean-field two-fluid model (RMF-TFM) and the relativistic Landau-Vlasov equation shows good agreement in the gross properties of the equilibration process.
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.
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.
115321070
On the relationship between Boltzmann-Langevin and Boltzmann-Uehling-Uhlenbeck models
195334493
Quantum simulations of strongly coupled quark-gluon plasma
A strongly coupled quark-gluon plasma (QGP) of heavy constituent quasi-particles is studied by a path-integral Monte-Carlo method. This approach is a quantum generalization of the classical molecular dynamics by Gelman, Shuryak, and Zahed. It is shown that this method is able to reproduce the QCD lattice equation of state. The results indicate that the QGP reveals liquid-like rather than gaslike properties. Quantum effects turned out to be of prime importance in these simulations.
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)
126372642
Logarithmic and Power Scaling Violation in Lepton Deep Inelastic Scattering. Data {QCD} Analysis
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.
9894980
Transverse QCD dynamics near the light cone
Starting from the QCD Hamiltonian in near-light cone coordinates, we study the dynamics of the gluonic zero modes. Euclidean 2+1 dimensional lattice simulations show that the gap at strong coupling vanishes at intermediate coupling. This result opens the possibility to synchronize the continuum limit with the approach to the light cone.
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.
124036154
ON INFLUENCE OF TWIST CORRECTIONS UPON SIN**2-theta-w