Effective Restoration of the U_A(1) symmetry in the SU(3) linear sigma model

Abstract

The effective restoration of the chiral U(A)(1) symmetry in strong interactions is studied using the linear chiral SU(3)xSU(3) model at finite temperatures. We find that the disappearance of the chiral anomaly causes a considerable change in the meson mass spectrum. We propose several signals for detecting this chiral phase in ultrarelativistic heavy-ion collisions: The eta/pi0 ratio is enhanced by an order of magnitude, the a0 is suppressed in the K+K- mass spectrum, and the scalar kappa meson appears as a peak just below the K*(892) in the invariant piK mass spectrum.

Comments: 4 pages, RevTeX, 3 postscript figures, new figure with spectral function, references to NJL model added, discussion about scalar meson mass spectrum and lattice data modified, editorially approved for publication in Phys. Rev. Lett