Hydrodynamics with spontaneous symmetry breaking: application to relativistic heavy ion collisions

In this paper we apply hydrodynamics for systems with continuous broken symmetries to heavy ion collisions in the framework of (1+1) dimensional Bjorken model. The temperature profile with respect to proper time determined in that context exhibits no differences with the ideal fluid. On the contrary, it is shown that the profile obtained when M\"{u}ller-Israel-Stewart second order theory of dissipation is included on top of standard hydrodynamics indicates a slower cooling of the system.Comment: 5 pages, 2 figures, version accepted for publication as a Brief Report in Physical Review

Introduction aux incertitudes de mesures

Les incertitudes évaluées en utilisant les normes internationales sont entrées dans les programmes de terminales scientifiques. Les livres de physique, destinés aux élèves, sont un peu justes pour les enseignants. Cet article a pour objectif de présenter les notions nécessaires à une bonne application des formules utiles

200 ans après Laplace, l’essor des méthodes bayésiennes d’analyse des données

International audienceInitiée par Pierre-Simon de Laplace il y a deux cents ans, l’analyse bayésienne des données expérimentales est en plein essor. Elle a fait son entrée dans certaines normes internationales de métrologie. Le but de cet article est d’introduire simplement le changement philosophique sous-jacent.Des applications à différents types de mesurages sont présentées

Nuclear response for the Skyrme effective interaction with zero-range tensor terms. II. Sum rules and instabilities

The formalism of linear response theory for Skyrme forces including tensor terms presented in article [1] is generalized for the case of a Skyrme energy density functional in infinite matter. We also present analytical results for the odd-power sum rules, with particular attention to the inverse energy weighted sum rule, $M_{-1}$, as a tool to detect instabilities in Skyrme functionals.Comment: Submitted to Phys. Rev.

200 ans après Laplace, l’essor des méthodes bayésiennes d’analyse des données

International audienceInitiée par Pierre-Simon de Laplace il y a deux cents ans, l’analyse bayésienne des données expérimentales est en plein essor. Elle a fait son entrée dans certaines normes internationales de métrologie. Le but de cet article est d’introduire simplement le changement philosophique sous-jacent.Des applications à différents types de mesurages sont présentées

Surface energy coefficient of a N2LO Skyrme energy functional : a semiclassical Extended Thomas-Fermi approach

We generalize to N2LO Skyrme functionals the semi-classical approach of Grammaticos and Voros in order to calculate the Extended Thomas Fermi expressions of the new densities and currents appearing at the N2LO level. Within a one dimensional symmetric semi infinite nuclear matter model and using a simple Fermi-like density profile, we obtain an easy-to-use formula for the surface energy including the contributions of the central, density-dependent and spin-orbit terms up to $\hbar^2$. Such a formula can be easily used as a first attempt to constrain the surface properties of new N2LO Skyrme parametrizations. The N2LO parametrization tested in this paper is shown to exhibit a shift (compared to a full Hartree-Fock calculation) which is quantitatively similar to the one obtained with the traditional Skyrme parametrizations.Comment: 19 pages, 3 figures, to be publishe

Surface energy coefficient of a N2LO Skyrme energy functional : a semiclassical Extended Thomas-Fermi approach

We generalize to N2LO Skyrme functionals the semi-classical approach of Grammaticos and Voros in order to calculate the Extended Thomas Fermi expressions of the new densities and currents appearing at the N2LO level. Within a one dimensional symmetric semi infinite nuclear matter model and using a simple Fermi-like density profile, we obtain an easy-to-use formula for the surface energy including the contributions of the central, density-dependent and spin-orbit terms up to $\hbar^2$. Such a formula can be easily used as a first attempt to constrain the surface properties of new N2LO Skyrme parametrizations. The N2LO parametrization tested in this paper is shown to exhibit a shift (compared to a full Hartree-Fock calculation) which is quantitatively similar to the one obtained with the traditional Skyrme parametrizations

What can we learn from the fission time of the super-heavy elements?

International audienceRecent experiments performed at GANIL with a crystal blocking technique have shown direct evidences of long fission times in the Super-Heavy Elements (SHE) region. Aimed to localize the SHE island of stability, can these experiments give access to the fission barrier and then to the shell-correction energy? In this paper, we calculate the fission time of heavy elements by using a new code, KEWPIE2, devoted to the study of the SHE.We also investigate the effect of potential structure beyond the saddle on the fission time