Stopping: from peripheral to central nuclear collisions at the SPS

New results on baryon stopping at the CERN SPS, measured by the inclusive net proton ($p$-$p$) rapidity distribution, are presented for centrality selected Pb+Pb and $p$+Pb, as well as minimum bias $p$+$p$ collisions. A smooth evolution in the degree of stopping is observed when going from small to large systems, with the greatest stopping in the most central $p$+Pb collisions. On the other hand, longitudinal distributions of produced particles vary little with the size of the system, and the total yield of pions scales approximately with the number of participating nucleons. (9 refs).