Transverse energy, charged particle pseudorapidity distributions and photon transverse momentum spectra have been studied as a function of the number of participants (N_{ part}) and the number of binary nucleon-nucleon collisions (N_{ coll}) in 158 A GeV Pb+Pb collisions over a wide impact parameter range. A scaling of the transverse energy pseudorapidity density at midrapidity as N_{ part}^{ 1.08 \pm 0.06} and N_{ coll}^{ 0.83 \pm 0.05} is observed. For the charged particle pseudorapidity density at midrapidity we find a scaling as N_{ part}^{ 1.07 \pm 0.04} and N_{ coll}^{ 0.82 \pm 0.03}. This faster than linear scaling with N_{ part} indicates a violation of the naive Wounded Nucleon Model.
Categories: nucl-ex