“…The multiplicity detector of the NA50 experiment, with its good granularity, allows to measure the charged particle multiplicity as a function of pseudorapidity, providing in particular the particle density at midrapidity. This observable gives information about initial conditions such as the energy density, whose knowledge is relevant for the interpretation of the anomalous J/ψ suppression, observed by the NA50 experiment in Pb-Pb collisions [1,2,3], in terms of the threshold for the creation of a new state of matter.…”