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Nuclear Theory·nucl-th

Thursday·March 26, 2015

13 papers—6 primary·7 cross-listed

All13Primary6Cross-lists7
  1. 01

    Sub-threshold and production by high mass resonances with UrQMD

    Jan Steinheimer🇩🇪 · Marcus Bleicher🇩🇪

    We present a possible explanation for the deep sub-threshold, and production yields measured with the HADES experiment in Ar+KCl reactions at A GeV and present predictions for Au+Au reactions at A GeV. To explain the surprisingly high yields of and hadrons we propose new decay channels for high mass baryon resonances. These new decay channels are constrained by elementary cross sections, and production in p+Nb. Based on the fits to the elementary reactions one obtains a satisfactorily description of and production in deep sub-threshold Ar+KCl reactions as well as the observed nuclear transparency ratio in proton induced production in cold nuclear matter. The results implicate that no new medium effects are required to describe the rare strange particle production data in low energy nuclear collisions.

    nucl-thnucl-exJ.Phys.G(2016)·74 citations
  2. 02

    Effects of the Inverse Square Potential on Nucleon-Nucleon Elastic Scattering in the Bethe-Salpeter Equation

    Susumu Kinpara🇯🇵

    Bethe-Salpeter equation is applied to nucleon-nucleon elastic scattering at the intermediate energy. The differential cross section and the polarization are calculated in terms of the phase shift analysis method using the two-body potential derived from the Bethe-Salpeter equation. The lowest-order Born approximation for the K-matrix is corrected by including the inverse square part of the potential.

    nucl-th1 citation
  4. 04

    Hydrodynamic modeling of pseudorapidity flow correlations in relativistic heavy-ion collisions and the torque effect

    Piotr Bozek🇵🇱 · Wojciech Broniowski🇵🇱 · Adam Olszewski🇵🇱

    We analyze correlations between the event-plane angles in different intervals of pseudorapidity within the 3+1-dimensional viscous hydrodynamics with the Glauber-model initial conditions. As predicted earlier, the fluctuations in the particle production mechanism in the earliest stage, together with asymmetry of the emission profiles in pseudorapidity from the forward- and backward going wounded nucleons, lead to the torque effect, namely, decorrelation of the event-plane angles in distant pseudorapidity bins. We use two- or three-bin measures of correlation functions to quantify the effect, with the latter compared to the recent data from the CMS collaboration. We find a sizable torque effect, with magnitude larger at RHIC than at the LHC.

    nucl-thhep-phnucl-exPRC(2015)·31 citations
  5. 05

    Vector interaction enhanced bag model for astrophysical applications

    Thomas Klahn🇵🇱 · Tobias Fischer🇵🇱

    For quark matter studies in astrophysics the thermodynamic bag model (tdBAG) has been widely used. Despite its success it fails to account for various phenomena expected from Quantum-Chromo-Dynamics (QCD). We suggest a straightforward extension of tdBAG in order to take the dynamical breaking of chiral symmetry and the influence of vector interactions explicitly into account. As for tdBAG the model mimics confinement in a phenomenological approach. It is based on an analysis of the Nambu--Jona-Lasinio (NJL) model at finite density. Furthermore, we demonstrate how NJL and bag models in this regime follow from the more general and QCD based framework of Dyson-Schwinger (DS) equations in medium by assuming a simple gluon contact interaction. Based on our simple and novel model, we construct quark hadron hybrid equations of state (EoS) and study systematically chiral and deconfinement phase transitions, the appearance of -quarks and the role of vector interaction. We further study these aspects for matter in beta-equilibrium at zero temperature, with particular focus on the current ~2 solar masses maximum mass constraint for neutron stars. Our approach indicates that the currently only theoretical evidence for the hypothesis of stable strange matter is an artifact of tdBAG and results from neglecting the dynamical breaking of chiral symmetry.

    nucl-thastro-ph.HEhep-phApJ(2015)·152 citations
  6. 06

    Nonconformal viscous anisotropic hydrodynamics

    Dennis Bazow🇺🇸 · Ulrich W. Heinz🇺🇸 · Mauricio Martinez🇺🇸

    We generalize the derivation of viscous anisotropic hydrodynamics from kinetic theory to allow for non-zero particle masses. The macroscopic theory is obtained by taking moments of the Boltzmann equation after expanding the distribution function around a spheroidally deformed local momentum distribution whose form has been generalized by the addition of a scalar field that accounts non-perturbatively (i.e. already at leading order) for bulk viscous effects. Hydrodynamic equations for the parameters of the leading-order distribution function and for the residual (next-to-leading order) dissipative flows are obtained from the three lowest moments of the Boltzmann equation. The approach is tested for a system undergoing (0+1)-dimensional boost-invariant expansion for which the exact solution of the Boltzmann equation in relaxation time approximation is known. Nonconformal viscous anisotropic hydrodynamics is shown to approximate this exact solution more accurately than any other known hydrodynamic approximation.

    nucl-thhep-phPRC(2015)·60 citations

Affiliations

first authorsco-authorsvia INSPIRE