Strangeness in ultrarelativistic nuclear collisions
  A model for description of the s_{NN}^{1/2} dependence of K+/pi+ ratio at the CERN SPS and upper AGS energies is proposed. It uses hadronic degrees of freedom and the amount of produced strangeness is mainly controlled by the total lifetime of the fireball. Decreasing lifetime with increasing collision energy is conjectured. 
Boris Tomasik