arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0901.2407hep-phhep-latnucl-th
收藏

热稠密QCD中的U_A（1）反常与临界面

U_A(1) Anomaly in Hot and Dense QCD and the Critical Surface

Jiunn-Wei Chen, Kenji Fukushima, Hiroaki Kohyama, Kazuaki Ohnishi, Udit Raha

备注：
8 pages, 5 figures
发表信息：
Phys.Rev.D80:054012,2009
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

讨论了热稠密QCD中三种轻味的手征相变。受U_A（1）反常能引起一级相变这一众所周知的事实的启发，我们研究了有限密度下U_A（1）对称性可能恢复的效应。特别地，我们探讨了U_A（1）恢复与de Forcrand和Philipsen最近的格点量子色动力学结果之间的联系，其中当μ增大时，在夸克质量和μ空间中，零化学势（μ）附近的一级相变区域缩小。从Ginzburg-Landau理论出发进行一般性讨论，然后使用Nambu-Jona-Lasinio模型进行定量研究。用密度依赖的t Hooft相互作用模型的部分U_A（1）恢复，拟合了de Forcrand和Philipsen的晶格计算中发现的低μ下临界面的收缩。在较高的mu下，临界表面可能会收缩或膨胀，这取决于场景。这就提出了这样一种可能性，即尽管临界面在较低的μ下收缩，但由于在较高的μ下膨胀，QCD临界端点可能仍然存在。在这种情况下，将需要非常高精度的晶格数据来检测临界表面的后弯，与目前可用的解析延拓或泰勒展开方法。然而，格点计算可以通过计算η '质量或小μ处的拓扑磁化率来检验U_A（1）恢复是否是临界表面收缩的原因。

英文摘要：

We discuss the chiral phase transition in hot and dense QCD with three light flavors. Inspired by the well known fact that the U_A(1) anomaly could induce first order phase transitions, we study the effect of the possible restoration of the U_A(1) symmetry at finite density. In particular, we explore the link between the U_A(1) restoration and the recent lattice QCD results of de Forcrand and Philipsen, in which the first order phase transition region near zero chemical potential (mu) shrinks in the quark mass and mu space when mu is increased. Starting from the Ginzburg-Landau theory for general discussions, we then use the Nambu--Jona-Lasinio model for quantitative studies. With the partial U_A(1) restoration modeled by the density dependent 't Hooft interaction, we fit the shrinking of the critical surface found in de Forcrand and Philipsen's lattice calculation at low mu. At higher mu, the critical surface might shrink or expand, depending on the scenarios. This raises the possibility that despite the shrinking of the critical surface at lower mu, the QCD critical end point might still exist due to the expansion at higher mu. In this case, very high precision lattice data will be needed to detect the back-bending of the critical surface with the currently available analytic continuation or Taylor expansion approaches. Lattice computations could, however, test whether the U_A(1) restoration is responsible for the shrinking of the critical surface by computing eta' mass or the topological susceptibility at small mu.

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。

↑