INDICATIONS FOR THE ONSET OF DECONFINEMENT IN Pb + Pb COLLISIONS AT THE CERN SPS FROM NA49

摘要

Particle production in central Pb+Pb collisions was studied with the NA49 large acceptance spectrometer at the CERN SPS at beam energies of 20, 30, 40, 80, and 158 GeV per nucleon. A change of the energy dependence is observed around 30A GeV for the yields of pions and strange particles as well as for the shapes of the transverse mass spectra. At present only a reaction scenario with onset of deconfmement is able to reproduce the measurements.