95 07 39 5 v 3 1 A ug 1 99 5 LBL - 37539 Partial U ( 1 ) A Restoration and η Enhancement in High - Energy Heavy - Ion Collisions
نویسنده
چکیده
We calculate the thermally averaged rates for the η-π conversion and η scattering using the Di Vecchia-Veneziano model and t’ Hooft model, which incorporate explicitly the U(1)A anomaly. Assuming an exponential suppression of the U(1)A anomaly, we also take into account the partial restoration of U(1)A symmetry at high temperatures. We find that the chemical equilibrium between η and π breaks up considerably earlier than the thermal equilibrium. Two distinct scenarios for the η freeze-out are discussed and the corresponding chemical potentials are calculated. We predict an enhancement of the thermal η-production as a possible signal of the partial U(1)A restoration in high-energy heavy-ion collisions. 11.30.Rd, 11.30.Qc, 12.38.Mh Typeset using REVTEX ∗Address after August 1, 1995: Department of Physics, University of Arizona, Tucson, AZ 85721. 1
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