$J/\ddot{I}ˆ$ reaction mechanisms and suppression in the nuclear medium

Abstract

Recent studies of the interaction of vector mesons with nuclei make possible and opportune the study of the interaction of the $J/\ddot{I}ˆ$ with nuclei and the investigation of the origin of the $J/\ddot{I}ˆ$ suppression in its propagation thorough a nuclear medium. We observe that the transition of $J/\ddot{I}ˆN$ to $VN$ with $V$ being a light vector, $\ddot{I},\ddot{I}‰,\ddot{I}•$, together with the inelastic channels, $J/\ddot{I}ˆN\to \bar{D}\hat{I}{›}_c$ and $J/\ddot{I}ˆN\to \bar{D}\hat{I}{\pounds }_c$ leads to a particular shape of the inelastic cross section. Analogously, we consider the mechanisms where the exchanged $D$ collides with a nucleon and gives $\ddot{I}€\hat{I}{›}_c$ or $\ddot{I}€\hat{I}{\pounds }_c$. The cross section has a peak around $\sqrt{s}=4415$ MeV, where the $J/\ddot{I}ˆN$ couples to a resonance predicted recently. We study the transparency ratio for electron induced $J/\ddot{I}ˆ$ production in nuclei at about 10 GeV and find that 30 - 35% of the $J/\ddot{I}ˆ$ produced in heavy nuclei are absorbed inside the nucleus. This ratio is in line with depletions of $J/\ddot{I}ˆ$ though matter observed in other reactions.

17 pages, 11 figures, this is the new version after replacement action