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arXiv · hep-ph/9507395

Partial $U(1)_A$ Restoration and $η$ Enhancement in High-Energy Heavy-Ion Collisions

Zheng Huang·Xin-Nian Wang
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Abstract

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.

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Zheng Huang, Xin-Nian Wang. 1995-08-01. Partial $U(1)_A$ Restoration and $η$ Enhancement in High-Energy Heavy-Ion Collisions. https://doi.org/10.1103/physrevd.53.5034

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