标题： $K^+$和$K^0$介子在1.528 AGeV下的相对产率的同位旋依赖性 显示英文标题

标题： Isospin dependence of relative yields of $K^+$ and $K^0$ mesons at 1.528 AGeV

摘要： $K^+$和$K^0$介子在入射动能为1.528$A$GeV 的$^{96}_{44}$Ru +$^{96}_{44}$Ru 和$^{96}_{40}$Zr +$^{96}_{40}$Zr 碰撞中的实验结果，利用GSI-Darmstadt的FOPI探测器进行测量，被研究作为高密度核物质中同位旋效应的可能探针。 测量的双比值 ($K^+/K^0$)$_{Ru}$/($K^+/K^0$)$_{Zr}$与热模型和相对论平均场输运模型的预测进行了比较，使用了两种不同的碰撞情景，并在对对称能量刚度的不同假设下进行。 我们发现与热模型预测和无限核物质对称能量较软的假设有良好的一致性，而更现实的碰撞输运模拟与数据也表现出相似的一致性，但也显示出对对称项的敏感性降低。 显示英文摘要

摘要： 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.