Volume 80, Number 2, October 2007
Article Number 22002
Number of page(s) 6
Section Nuclear Physics
Published online 28 September 2007
EPL, 80 (2007) 22002
DOI: 10.1209/0295-5075/80/22002

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

A. Mekjian

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 in final form 3 September 2007; published October 2007
published online 28 September 2007

A fundamental symmetry of nuclear and particle physics is isospin whose third component is the Gell-Mann/Nishijima expression IZ = Q-(B+S)/2. The role of isospin symmetry in relativistic heavy-ion collisions is studied. An isospin IZ, 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 N = Z and asymmetric N $\ne$ Z systems. By contrast, in a hadron phase, a IZ/S correlation exists as long as the electrostatic charge chemical potential $\mu _{Q}$ $\ne$ 0 as in N $\ne$ Z asymmetric systems. A parallel is drawn with a Zeeman effect which breaks a spin degeneracy.

25.75.-q - Relativistic heavy-ion collisions.
25.75.Gz - Particle correlations.
25.75.Nq - Quark deconfinement, quark-gluon plasma production, and phase transitions.

© Europhysics Letters Association 2007