02 00 9 v 2 7 M ay 2 00 3 The universal ψ ′ ′ / ψ ′ ratio as unambiguous signature for hard physics in nuclear reactions and in decays of beauty hadrons

We suggest the ratio of the ψ′′(3770)/ψ′(3686) production cross sections as an unambiguous probe of the dominance of hard, pointlike physics in charmonium production. If hard physics dominates the charmonium production the ratio : σ(ψ ) σ(ψ) ≈ Γ(ψ→ll) Γ(ψ′→l+l−) ≈ 0.1 is independent of the process. We argue that since the dominant DD̄ decay mode of the ψ′′-meson can be detected with a high efficiency at the current facilities the effective counting rate for the ψ′′ production should be comparable to that of the ψ′ and hence it could be observed at the B-factories. Even in hadron induced processes the ratio will not be changed significantly by final state interactions due to the similar mass and size of these two charmonium states. A possible exception are the charmonium state interactions with low energy particles – comovers – which are especially relevant for the heavy ion collisions. The production of the charmonium states in inclusive hadron-hadron collisions remains one of the challenges for the theory. Understanding of the charmonium production dynamics is important for a number of applications. This includes the dynamics of B → J/ψ+X decays which play an important