%0 Generic
%A Zinyuk, Victoria
%D 2016
%F heidok:20725
%R 10.11588/heidok.00020725
%T Systematic study of strangeness production and   dynamic behaviour with the FOPI experiment  at SIS-18
%U https://archiv.ub.uni-heidelberg.de/volltextserver/20725/
%X This work is dedicated to the investigation of in-medium behaviour of strange particles.       In-medium production and propagation of $K^+$  and $K^-$ mesons is studied with the FOPI apparatus    in $^{58}$Ni\,+\,$^{58}$Ni collisions at the incident beam energy of $E_{beam}$= 1.91 AGeV, i.e.     near the strangeness production threshold energies.   Weak in-plane `anti\,-\,flow'  with respect to protons and a slight `squeeze-out'   is found in the azimuthal emission pattern of $K^{+}$ mesons.   $K^{-}$ mesons exhibit an isotropic emission pattern within large statistic uncertainties.   The comparison to the predictions of two independent transport calculations, HSD and IQMD, suggests   a weakly repulsive $KN$ in-medium potential of $U_{KN} = 20 \pm 5$\,MeV and an attractive   $\bar{K}N$ in\,-\,medium potential of $U_{K^{-}N} = -40 \pm 10$\,MeV.       Production of $K^{+/-/0}$, $\phi$ mesons and the $\Lambda$ baryon at normal nuclear matter density     is studied in $\pi^-+A$ reactions with C, Cu and Pb targets at incident beam momentum of $p_{\pi^-}$= 1.7 GeV/$c$.    Differences in the final state phase space distributions measured in heavy and light targets point to     repulsion for $K^+$ and $K^0_S$ mesons in nuclear medium. The latter is solely attributed to the strong interaction.    The corresponding comparison for $K^-$ mesons suggests a strong absorption in nuclear medium.    Observed  $\phi$ meson yields  support the hypothesis of $Z^{\alpha}$\,-\,scaling of the production cross section.