Isospin and isospin/strangeness correlations in relativistic heavy-ion collisions

Rutgers University, Department of Physics and Astronomy - Piscataway, NJ 08854, USA and California Institute of Technology, Kellogg Radiation Lab 106-38 - Pasadena, CA 91125, USA

Received: 3 July 2007
Accepted: 3 September 2007

Abstract

A fundamental symmetry of nuclear and particle physics is isospin whose third component is the Gell-Mann/Nishijima expression . The role of isospin symmetry in relativistic heavy-ion collisions is studied. An isospin I_Z, strangeness S correlation is shown to be a direct and simple measure of flavor correlations, vanishing in a Qg phase of uncorrelated flavors in both symmetric and asymmetric N Z systems. By contrast, in a hadron phase, a correlation exists as long as the electrostatic charge chemical potential   0 as in N  Z asymmetric systems. A parallel is drawn with a Zeeman effect which breaks a spin degeneracy.