$J/ψ$ suppression in Pb+Pb collisions and $p_T$ broadening

Abstract

We have analysed the NA50 data, on the centrality dependence of $p_T$ broadening of $J/ψ$'s, in Pb+Pb collisions, at the CERN-SPS. The data were analysed in a QCD based model, where $J/ψ$'s are suppressed in 'nuclear' medium. Without any free parameter, the model could explain the NA50 $p_T$ broadening data. The data were also analysed in a QGP based threshold model, where $J/ψ$ suppression is 100% above a critical density. The QGP based model could not explain the NA50 $p_T$ broadening data. We have also predicted the centrality dependence of $J/ψ$ suppression and $p_T$ broadening at RHIC energy. Both the models, the QGP based threshold model and the QCD based nuclear absorption model, predict $p_T$ broadening very close to each other.