Figure 1

Ratio of the $\psi({\rm 2S})$ and J/$\psi$ cross sections as a function of $\langle N_{\rm part}\rangle$. To remove the contamination from photoproduced charmonium, only $\psi({\rm 2S})$ and J/$\psi$ having $p_{\rm T}>0.3$ GeV/$c$ are considered in the two most peripheral classes. The vertical error bars and the filled boxes represent statistical and systematic uncertainties, respectively. In the lower panel the ratios are normalized to the corresponding pp value (double ratio) Data are compared to predictions of the TAMU  and SHMc  models and to results of the SPS NA50 experiment . The filled boxes around the line at unity indicate the global systematic uncertainties.