中能重离子碰撞输运模型计算中的双峰现象
Bimodality emerges from transport model calculations of heavy ion collisions at intermediate energy
摘要：
这项工作是我们努力的延续[Phys. Rev. C 91，034616（2015）]，以检查是否可以从中能重离子碰撞的输运模型计算中提取相变的特征。一阶相变的特征是在有限系统中出现$P_m(k)$的双峰分布。这里P_m（k）是多重性分布的最大值出现在质量数k处的概率。使用一个著名的事件生成模型（BUU加上波动），我们做了两种情况下的中心碰撞：质量40对质量40和质量120对质量120。在这两种情况下都可以看到双峰。结果与统计模型计算结果十分相似。一个有趣的特征被发现了。我们观察到，在双峰出现的能量处。出现其它类似相变的特征。在某些一阶导数中存在间断。然后，我们检查，如果出现这样的突破标准Botzmann-Uehling-Uhlenbeck（BUU）计算没有波动。他们会去的而且其含义很有趣。如果发生一阶相变，则可以从普通BUU计算中识别。可能是因为这方面以前没有研究过，所以现在还没有看到。
英文摘要：
This work is a continuation of our effort [Phys. Rev. C 91, 034616 (2015)] to examine if signatures of a phase transition can be extracted from transport model calculations of heavy ion collisions at intermediate energy. A signature of first order phase transition is the appearance of a bimodal distribution in $P_m(k)$ in finite systems. Here P_m(k) is the probability that the maximum of the multiplicity distribution occurs at mass number k. Using a well-known model for event generation (BUU plus fluctuation), we do two cases of central collision: mass 40 on mass 40 and mass 120 on mass 120. Bimodality is seen in both the cases. The results are quite similar to those obtained in statistical model calculations. An intriguing feature is seen. We observe that at the energy where bimodality occurs. other phase transition like signatures appear. There are breaks in certain first order derivatives. We then examine if such breaks appear in standard Botzmann-Uehling-Uhlenbeck (BUU) calculations without fluctuations. They do. The implication is interesting. If first order phase transition occurs, it may be possible to recognise that from ordinary BUU calculation. Probably the reason this was not seen already is because this aspect was not investigated before.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
