Isospin dependence of relative yields of K + and K 0 mesons at 1.528 AGeV
Abstract
Results on
K
+
and
K
0
meson production in
96
44
Ru +
96
44
Ru and
96
40
Zr +
96
40
Zr collisions at a beam kinetic energy of 1.528
A
GeV, measured with the FOPI detector at GSI-Darmstadt, are investigated as a possible probe of isospin effects in high density nuclear matter. The measured double ratio (
K
+
/
K
0
)
Ru
/(
K
+
/
K
0
)
Zr
is compared to the predictions of a thermal model and a Relativistic Mean Field transport model using two different collision scenarios and under different assumptions on the stiffness of the symmetry energy. We find a good agreement with the thermal model prediction and the assumption of a soft symmetry energy for infinite nuclear matter while more realistic transport simulations of the collisions show a similar agreement with the data but also exhibit a reduced sensitivity to the symmetry term.