Production of K+ and of K- Mesons in Heavy-Ion Collisions from 0.6 to 2.0 AGeV Incident Energy
A. Foerster, F. Uhlig, I. Boettcher, D. Brill, M. Debowski, F. Dohrmann, E. Grosse, P. Koczon, B. Kohlmeyer, S. Lang, F. Laue, M. Mang, M. Menzel, C. Muentz, L. Naumann, H. Oeschler, M. Ploskon, W. Scheinast, A. Schmah, T. J. Schuck, E. Schwab, P. Senger, Y. Shin, J. Speer, H. Stroebele, C. Sturm, G. Surowka, A. Wagner, W. Walus
Abstract
This paper summarizes the yields and the emission patterns of K+ and of K- mesons measured in inclusive C+C, Ni+Ni and Au+Au collisions at incident energies from 0.6 AGeV to 2.0 AGeV using the Kaon Spectrometer KaoS at GSI. For Ni+Ni collisions at 1.5 and at 1.93 AGeV as well as for Au+Au at 1.5 AGeV detailed results of the multiplicities, of the inverse slope parameters of the energy distributions and of the anisotropies in the angular emission patterns as a function of the collision centrality are presented. When comparing transport-model calculations to the measured K+ production yields an agreement is only obtained for a soft nuclear equation of state (compression modulus KN ~ 200 MeV). The production of K- mesons at energies around 1 to 2 AGeV is dominated by the strangeness-exchange reaction K- N <-> pi Y (Y = Lambda, Sigma) which leads to a coupling between the K- and the K+ yields. However, both particle species show distinct differences in their emission patterns suggesting different freeze-out conditions for K+ and for K- mesons.