The thermal fit to preliminary HADES data of Au+Au collisions at $\sqrt{s_{{}_{NN}}}=2.4$ GeV shows two degenerate solutions at $T\approx 50$ MeV and $T\approx 70$ MeV. The analysis of the same particle yields in a transport simulation of the UrQMD model yields the same features, i.e. two distinct temperatures for the chemical freeze-out. While both solutions yield the same number of hadrons after resonance decays, the feeddown contribution is very different for both cases. This highlights that two systems with different chemical composition can yield the same multiplicities after resonance decays. The nature of these two minima is further investigated by studying the time-dependent particle yields and extracted thermodynamic properties of the UrQMD model. It is confirmed, that the evolution of the high temperature solution resembles cooling and expansion of a hot and dense fireball. The low temperature solution displays an unphysical evolution: heating and compression of matter with a decrease of entropy. These results imply that the thermal model analysis of systems produced in low energy nuclear collisions is ambiguous but can be interpreted by taking also the time evolution and resonance contributions into account.

Au+Au 碰撞的初步 HADES 数据的热拟合 $\sqrt{{秒}_{{}_{NN}}}=2.4$ GeV 显示了两个退化的解决方案 $吨\approx 50$ MeV 和 $吨\approx 70$兆伏。在 UrQMD 模型的传输模拟中对相同粒子产量的分析产生相同的特征，即化学冻结的两个不同温度。虽然两种解决方案在共振衰减后产生相同数量的强子，但两种情况下的反馈贡献非常不同。这突出表明，在共振衰减后，具有不同化学成分的两个系统可以产生相同的多重性。通过研究 UrQMD 模型的时间相关粒子产率和提取的热力学特性，进一步研究了这两个最小值的性质。经证实，高温溶液的演化类似于炽热致密火球的冷却和膨胀。低温解决方案显示出非物理演化：物质加热和压缩，熵减少。