2,864 research outputs found

    Topics on Hydrodynamic Model of Nucleus-Nucleus Collisions

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    A survey is given on the applications of hydrodynamic model of nucleus-nucleus collisons, focusing especially on i) the resolution of hydrodynamic equations for arbitrary configurations, by using the smoothed-particle hydrodynamic approach; ii) effects of the event-by-event fluctuation of the initial conditions on the observables; iii) decoupling criteria; iv) analytical solutions; and others.Comment: 30 pages, 29 figures; corrected typo

    On the necessity to include event-by-event fluctuations in experimental evaluation of elliptical flow

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    Elliptic flow at RHIC is computed event-by-event with NeXSPheRIO. We show that when symmetry of the particle distribution in relation to the reaction plane is assumed, as usually done in the experimental extraction of elliptic flow, there is a disagreement between the true and reconstructed elliptic flows (15-30% for η\eta=0, 30% for p⊥p_\perp=0.5 GeV). We suggest a possible way to take into account the asymmetry and get good agreement between these elliptic flows

    Effects of LatticeQCD EoS and Continuous Emission on Some ObseErvables

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    Effects of lattice-QCD-inspired equations of state and continuous emission on some observables are discussed, by solving a 3D hydrodynamics. The particle multiplicity as well as v2 are found to increase in the mid-rapidity. We also discuss the effects of the initial-condition fluctuations.Comment: 6 pages, 10 figures, prepared for Workshop on Particle Correlations and Fentoscopy, Kromeriz (Czech Republic), Aug. 15-17,200

    First results from the VIMOS-IFU survey of gravitationally lensing clusters at z~0.2

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    We present the on-going observational program of a VIMOS Integral Field Unit survey of the central regions of massive, gravitational lensing galaxy clusters at redshift z~0.2. We have observed six clusters using the low-resolution blue grism (R about 200), and the spectroscopic survey is complemented by a wealth of photometric data, including Hubble Space Telescope optical data and near infrared VLT data. The principal scientific aims of this project are: the study of the high-z lensed galaxies, the transformation and evolution of galaxies in cluster cores and the use of multiple images to constrain cosmography. We briefly report here on the first results from this project on the clusters Abell 2667 and Abell 68.Comment: 5 pages, 5 figures. To appear in "Sciences Perspectives for 3D Spectroscopy. ESO Astrophysics Symposia". Ed by M.Kissler-Patig, M.M. Roth and J.R. Wals

    Ψ=We±Φ\rm \Psi= W e^{\pm \Phi} quantum cosmological solutions for Class A Bianchi Models

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    We find solutions for quantum Class A Bianchi models of the form Ψ=We±Φ\rm \Psi=W e^{\pm \Phi} generalizing the results obtained by Moncrief and Ryan in standard quantum cosmology. For the II and IX Bianchi models there are other solutions Φ~2\rm \tilde\Phi_2, Φ~9\rm \tilde\Phi_9 to the Hamilton-Jacobi equation for which Ψ\rm \Psi is necessarely zero, in contrast with solutions found in supersymmetric quantum cosmology.Comment: 15 pages, Late

    Orbital Order Effect of Two-Dimensional Spin Gap System for CaV4O9

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    Effects of possible orbital order in magnetic properties of two-dimensional spin gap system for CaV4_4O9_9 are investigated theoretically. After analyzing experimental data, we show that single orbital models assumed in the literature are insufficient to reproduce the data. To understand the origin of the discrepancy, we assume that in d1d^1 state of V, dxzd_{xz} and dyzd_{yz} orbitals have substantial contributions in the lowest-energy atomic level which leads to a double-degeneracy. We study possible configurations of the orbital order. By exact diagonalization and perturbation expansion, we calculate the susceptibility, wavenumber dependence of low-lying excitations and equal-time spin-spin correlations which is related to integrated intensity of the neutron inelastic scattering. These quantities sensitively depend on the configuration of the orbital order. The calculated results for some configurations of the orbital order reproduce many experimental results much better than the previous single-orbital models. However some discrepancy still remains to completely reproduce all of the reported experimental results. To understand the origin of these discrepancies, we point out the possible importance of the partially occupied dxyd_{xy} orbital in addition to orbital order of partially filled dxzd_{xz} and dyzd_{yz} orbitals.Comment: 19 pages LATEX, 15 postscript figures, using jpsj.sty,to be published in J.Phys.Soc.Jpn. Vol.67 No.2 (1998

    NeXSPheRIO results on elliptic flow at RHIC and connection with thermalization

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    Elliptic flow at RHIC is computed event-by-event with NeXSPheRIO. Reasonable agreement with experimental results on v2(η)v_2(\eta) is obtained. Various effects are studied as well: reconstruction of impact parameter direction, freeze out temperature, equation of state (with or without crossover), emission mecanism.Comment: Contribution to the Proceedings of the Quark-Gluon Plasma Thermalization workshop. Content slightly increase

    Classical instability in Lovelock gravity

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    We introduce a simple method for the investigation of the classical stability of static solutions with a horizon in Lovelock gravity. The method is applicable to the investigation of high angular momentum instabilities, similar to those found by Dotti and Gleiser for Gauss-Bonnet black holes. The method does not require the knowledge of the explicit analytic form of the black hole solution. In this paper we apply our method to a case where the explicit solution is known and show that it identifies correctly the resulting unstable modes.Comment: 13 pages, 2 figure

    Minisuperspace Examples of Quantization Using Canonical Variables of the Ashtekar Type: Structure and Solutions

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    The Ashtekar variables have been use to find a number of exact solutions in quantum gravity and quantum cosmology. We investigate the origin of these solutions in the context of a number of canonical transformations (both complex and real) of the basic Hamiltonian variables of general relativity. We are able to present several new solutions in the minisuperspace (quantum cosmology) sector. The meaning of these solutions is then discussed.Comment: 23 pages, latex, 3 figures (uuencoded, separate file
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