The universal psi-prime-prime to psi-prime ratio as unambiguous signature for hard physics in nuclear reactions and in decays of beauty hadrons

Abstract

We suggest the ratio of the ${\psi }^{\prime \prime }(3770)/{\psi }^{\prime }(3686)$ production cross sections as an unambiguous probe of the dominance of hard, point-like physics in charmonium production. If hard physics dominates the charmonium production the ratio : $\frac{\sigma ({\psi }^{\prime \prime })}{\sigma ({\psi }^{\prime })}\approx \frac{\Gamma ({\psi }^{\prime \prime }\to l^{+}{l}^{-})}{\Gamma ({\psi }^{\prime }\to l^{+}{l}^{-})}\approx 0.1$ is independent of the process. We argue that since the dominant $D\bar{D}$ decay mode of the ${\psi }^{\prime \prime }$-meson can be detected with a high efficiency at the current facilities the effective counting rate for the ${\psi }^{\prime \prime }$ production should be comparable to that of the ${\psi }^{\prime }$ 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.

Comments: final version, 9 pages