$J/\psi$ reaction mechanisms and suppression in the nuclear medium

TL;DR

This paper investigates the interaction mechanisms and suppression effects of $J/$ mesons in nuclear matter, highlighting specific reaction channels, resonance effects, and absorption rates relevant to understanding $J/$ suppression in nuclear environments.

Contribution

It introduces detailed reaction mechanisms and resonance effects influencing $J/$ interactions with nuclei, providing new insights into suppression phenomena.

Findings

The inelastic cross section peaks around 4415 MeV due to resonance coupling.

Approximately 30-35% of $J/$ are absorbed in heavy nuclei.

The observed suppression aligns with experimental depletions in nuclear matter.

Abstract

Recent studies of the interaction of vector mesons with nuclei make possible and opportune the study of the interaction of the $J/\psi$ with nuclei and the investigation of the origin of the $J/\psi$ suppression in its propagation thorough a nuclear medium. We observe that the transition of $J/\psi N$ to $VN$ with $V$ being a light vector, $\rho, \omega,\phi$, together with the inelastic channels, $J/\psi N \to \bar D \Lambda_c$ and $J/\psi N \to \bar D \Sigma_c$ 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 $\pi \Lambda_c$ or $\pi \Sigma_c$. The cross section has a peak around $\sqrt s=4415$ MeV, where the $J/\psi N$ couples to a resonance predicted recently. We study the transparency ratio for electron induced $J/\psi$ production in nuclei at about 10 GeV and find that 30 - 35% of the $J/\psi$ produced in heavy nuclei are absorbed inside the nucleus. This ratio is in line with depletions of $J/\psi$ though matter observed in other reactions.