出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We present results of the CERN experiment NA52 which measures Pb+Pb
collisions at 158 A GeV. The topics we address are: 1. strangelet search, 2. nuclei and
antinuclei production and 3. strangeness production. No strangelets have been found. We
set upper limits which stretch down to the minimal values of 2 10−10 for negatively and
3 10−9 for positively charged strangelets. We observed 5 3He near midrapidity. Nuclei
and antinuclei cross sections suggest production mainly through coalescence, out of a
thermalised particle source, at the time of the thermal freeze-out as witnessed by their
temperature of 100-120 MeV. Charged kaons per participant nucleon (Np) show an onset
of enhancement followed by saturation at Np 80, corresponding approximately to an
initial energy density of i 1.3 GeV/fm3. This onset may be connected to the onset of
the QCD phase transition.
