C. Nonaka

Hydrodynamical analysis of hadronic spectra in the 130 GeV/nucleon Au + Au collisions

We study one-particle spectra and a two-particle correlation function in the 130 GeV/nucleon

(3+1)-dimensional relativistic hydrodynamical expansion of hot and dense matter in ultra-relativistic nuclear collision

mathrm{Au}+mathrm{Au}

Charge diffusion constant in hot and dense hadronic matter: A hadro-molecular-dynamics calculation

collisions at the Relativistic Heavy Ion Collider by making use of a hydrodynamical model. We calculate the one-particle hadronic spectra and present an analysis of Bose-Einstein correlation functions based on a numerical solution of the hydrodynamical equations which takes both longitudinal and transverse expansion into account appropriately. The hydrodynamical model provides excellent agreement with the experimental data in the pseudorapidity and the transverse momentum spectra of charged hadrons, the rapidity dependence of the antiproton-to-proton ratio, and almost consistent results for the pion Bose-Einstein correlation functions. Our numerical solution with a simple freeze-out picture suggests the formation of a quark-gluon plasma with large volume and low net-baryon density.

Calculation of the baryon diffusion constant in hot and dense hadronic matter based on an ultrarelativistic collision event generator

Abstract. A full (3+1)-dimensional calculation using Lagrangian hydrodynamics is proposed for relativistic nuclear collisions. This calculation enables us to evaluate the anisotropic flow of the hadronic matter which appears in non-central and/or asymmetrical relativistic nuclear collisions. Applying hydrodynamical calculations to the deformed uranium collisions in the AGS energy region, we discuss the nature of the space-time structure and particle distributions in detail.

Monte Carlo study of two-color QCD with finite chemical potential: Status report of Wilson fermion simulation

We evaluate the charge diffusion constant of dense and hot hadronic matter based on the molecular dynamical method by using a hadronic collision generator which describes nuclear collisions at energies 101 − 2 GeV/A and satisfies detailed balance at low temperatures (T ≤ 200 MeV). For the hot and dense hadronic matter in the temperature range T = 80–200 MeV and with baryon number density, nB, from 0.16fm−3 to 0.32fm−3, the charge diffusion constant D gradually increases from 0.5 fmc to 2 fmc with temperature and is almost independent of baryon number density. Based on the obtained diffusion constant, we make simple discussions on the diffusion of charge fluctuation in ultrarelativistic nuclear collisions.

Numerical analysis of a two-pion correlation function based on a hydrodynamical model

We generate the statistical ensembles in equilibrium with fixed temperature and chemical potential by imposing periodic boundary condition to the simulation of URASiMA(Ultra-Relativistic AA collision Simulator based on Multiple Scattering Algorithm). By using the generated ensembles, we investigate the temperature dependence and the chemical potential dependence of the nucleon diffusion constant of a dense and hot hadronic matter.

I = 0 scalar channel

Abstract Using Wilson fermions, we study SU(2) lattice QCD with the chemical potential at β = 1.6. The ratio of fermion determinants is evaluated at each Metropolis link update step. We calculate the baryon number density, the Polyakov loops and the pseudoscalar and vector masses on 4 4 and 4 3 × 8 lattices. Preliminary data show the pseudoscalar meson becomes massive around μ = 0.4, which indicates the chiral symmetry restoration. The calculation is broken down when approaching to the transition region. We analyze the behavior of the fermion determinant and eigen value distributions of the determinant, which shows a peculiar “Shell-and-Bean” pattern near the transition.

Lattice tool kit in Fortran90

We will numerically investigate two-particle correlation function of CERN– SPS 158 A GeV Pb+Pb central collisions in detail based on a (3+1)dimensional relativistic hydrodynamical model with first order phase transition. We use the Yano-Koonin-Podgoretskiuo parametrization as well as the usual Cartesian parametrization and analyze the pair momentum dependence of HBT radii extracted from the parametrizations. We find that the interpretation of the temporal radius parameters as the time duration in YKP parametrization is not available for the hydrodynamical model where the source became opaque naturally because of expansion and surface dominant freeze-out. Finally, effect of the phase transition on the source opacity is also discussed.

Analyses of collective flow and space-time evolution based on relativistic hydrodynamical model

Abstract Using lattice QCD with dynamical Wilson fermions, we study I = 0 and J P = 0 + channel which is constructed by , in order to search for the σ meson. Our preliminary result shows that the connected and disconnected diagrams contribute to the σ meson propagator in the same order.

Analysis of one-and two-particle spectra at RHIC based on a hydrodynamical model

Abstract We report a project to provide a set of free source codes for lattice QCD. The programs may be used as fundamental blocks when one wants to construct his/her own QCD codes. They are written in Fortran 90 with use of MODULE, so that algorithms can transparently be seen. MPI is used for parallelization. We are also constructing a proto-type of QCD-GRID where one can try to run the code.