Strangeness production in nuclear interactions at 200AGeV and the number of nucleon- nucleon collisions

Data on mean numbers of Λ, Λ̄, K’s and on the total number < ss̄ > of pairs of strange valence quarks in final state hadrons in hadronic and nuclear collisions at CERNSPS energies are studied as a function of the mean number < ncoll > of nucleonnucleon collisions. Results give indications of an almost linear dependence over most of the region of < ncoll >. This in turn points out to strangeness being produced mostly in the central rapidity region of nucleonnucleon collisions by a mechanism similar to a hard or semihard process. The available data are extrapolated to Pb+Pb interactions by two simple models, leading to < ss̄ >Pb+Pb≈ 300 ± 30. Observations exceeding these values of < ss̄ >Pb+Pb would give evidence of the onset of a new dynamical regime in Pb+Pb interactions.