标题： 奇异粒子比值在核碰撞中的快速度依赖性 显示英文标题

标题： Rapidity Dependence of Strange Particle Ratios in Nuclear Collisions

摘要： 最近发现，在200 A GeV的硫诱导核碰撞中，观察到的奇异强子丰度可以在一个热力学模型中得到解释，其中重子和介子分别处于相对化学平衡状态，整体奇异性略微未饱和，但根据相对化学平衡在奇异强子通道中分布，奇异夸克化学势为零。 我们发展了一个相对化学平衡概念的一致热力学公式，并展示了如何将偏离绝对化学平衡的偏差引入配分函数，例如整体奇异性未饱和或介子与重子之间化学平衡的破坏。 然后，我们利用现有数据检验假设，即奇异夸克化学势处处为零，且所有观测到的强子的快度分布仅能用一个与快度相关的函数$\mu_{\rm q}(\eta)$来解释重子化学势。 本研究的目的是阐明NA36实验中观测到的奇异重子比的强烈快度依赖性。 显示英文摘要

摘要： It was recently found that in sulphur-induced nuclear collisions at 200 A GeV the observed strange hadron abundances can be explained within a thermodynamic model where baryons and mesons separately are in a state of relative chemical equilibrium, with overall strangeness being slightly undersaturated, but distributed among the strange hadron channels according to relative chemical equilibrium with a vanishing strange quark chemical potential. We develop a consistent thermodynamic formulation of the concept of relative chemical equilibrium and show how to introduce into the partition function deviations from absolute chemical equilibrium, e.~g.~an undersaturation of overall strangeness or the breaking of chemical equilibrium between mesons and baryons. We then proceed to test on the available data the hypothesis that the strange quark chemical potential vanishes everywhere, and that the rapidity distributions of all the observed hadrons can be explained in terms of one common, rapidity-dependent function $\mu_{\rm q}(\eta)$ for the baryon chemical potential only. The aim of this study is to shed light on the observed strong rapidity dependence of the strange baryon ratios in the NA36 experiment.