Energy dependence of pion and kaon production in central Pb+Pb collisions
Abstract
Measurements of charged pion and kaon production in central Pb+Pb collisions at 40, 80, and 158 A GeV are presented. These are compared with data at lower and higher energies as well as with results from p+p interactions. The mean pion multiplicity per wounded nucleon increases approximately linearly with s1/4NN with a change of slope starting in the region 15-40 A GeV. The change from pion suppression with respect to p+p interactions, as observed at low collision energies, to pion enhancement at high energies occurs at about 40A GeV. A nonmonotonic energy dependence of the ratio of K+ to π+ yields is observed, with a maximum close to 40A GeV and an indication of a nearly constant value at higher energies. The measured dependences may be related to an increase of the entropy production and a decrease of the strangeness to entropy ratio in central Pb+Pb collisions in the low SPS energy range, which is consistent with the hypothesis that a transient state of deconfined matter is created above these energies. Other interpretations of the data are also discussed.
- Publication:
-
Physical Review C
- Pub Date:
- November 2002
- DOI:
- arXiv:
- arXiv:nucl-ex/0205002
- Bibcode:
- 2002PhRvC..66e4902A
- Keywords:
-
- 25.75.-q;
- Relativistic heavy-ion collisions;
- Nuclear Experiment;
- High Energy Physics - Experiment;
- High Energy Physics - Phenomenology
- E-Print:
- revised version to appear in Phys. Rev. C, 33 pages including 11 figures