Hadronic scattering effects on ψ(2S) suppression in relativistic heavy-ion collisions

Abstract

In this work we estimate the $N_{\psi \left(2S\right)}/N_{J/\psi }$ yield ratio in heavy-ion collisions, considering the interactions of the $\psi \left(2S\right)$ and $J/\psi$ states with light mesons in the hadron gas formed at the late stages of these collisions. Starting from the appropriate effective Lagrangians, we first compute the thermally-averaged cross sections for the production and absorption of the mentioned states, and then use them as input in the rate equations to determine the time evolution of $N_{\psi \left(2S\right)}$, $N_{J/\psi }$ and $N_{\psi \left(2S\right)}/N_{J/\psi }$. The main conclusion of our study is that the $\psi \left(2S\right)$ and $J/\psi$ multiplicities do not change much in the hadron gas phase and that the $\psi \left(2S\right)$ is more absorbed than the $J/\psi$. The obtained final ratio is in agreement with recent experimental data.