φ-enhancement and J/ψ suppression in nuclear collisions by rescattering of secondary hadrons

We point out that recent indications from the NA38 Collaboration for an increase of the φ/(ω+ρ0) ratio in central 200A GeV O+U and S+U collisions at CERN give evidence for an approach to chemical equilibrium in these systems. Under the assumption (which is supported by previous theoretical work) that the J/ψ suppression found in the same experiment under similar kinematic conditions is due to final state absorption via rescattering in the dense collision zone, we solve the rate equations for φ-production and -absorption via secondary collisions in the reaction zone. Eliminating unknown geometrical parameters of the collision zone by using the J/ψ suppression data, we obtain a quantitative description of the measured φ enhancement. (orig.)