System Size and Centrality Dependence of the Balance Function in A + A   Collisions at s(NN)^(1/2) = 17.2 GeV
  Electric charge correlations were studied for p+p, C+C, Si+Si and centrality selected Pb+Pb collisions at $\sqrt{s_{NN}} = 17.2$ GeV with the NA49 large acceptance detector at the CERN-SPS. In particular, long range pseudo-rapidity correlations of oppositely charged particles were measured using the Balance Function method. The width of the Balance Function decreases with increasing system size and centrality of the reactions. This decrease could be related to an increasing delay of hadronization in central Pb+Pb collisions. 
NA49 Collaboration