Dynamical Freeze-Out Phenomena: The Case of K±, φ Transverse Momentum Spectra in Collisions of Au(1.23 A GeV) + Au

Abstract

We argue on a continuous (dynamical) kinetic freeze-out of K ± , φ observed at midrapidity in collisions Au(1.23 A GeV) + Au. The simulations by means of a transport model of BUU type point to time independent transverse momentum slope parameters after 20 fm/c. The complex interplay of expansion dynamics and strangeness production/exchange/absorption as well as elastic scatterings involved in the reaction network does not support the previous interpretation of a late freeze-out of K − due to larger cross sections. 25.75.Dw; 25.75.Ld