Excitation function of K+ and π+ production in Au+Au reactions at 2–10 AGeV

Positive pion and kaon production from Au+Au reactions have been measured as a function of beam energy over the range 2.0–10.7 AGeV. Both the kaon and the pion production cross-sections at mid-rapidity are observed to increase steadily with beam kinetic energy. The ratio of K+ to π+ mid-rapidity yields increases from 0.0271±0.0015±0.0014 at 2.0 AGeV to 0.202±0.005±0.010 at 10.7 AGeV and is larger than the K+/π+ ratio from p+p reactions over the same beam energy region. There is no indication of a strong onset of any new production mechanism in heavy-ion reactions in this energy range beyond rescattering of hadrons.