Does non-monotonic behavior of directed flow signal the onset of deconfinement?

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• 作者：Yasushi Nara^a ; Akira Ohnishi^b
• 关键词：relativistic heavy-ion collisions ; quark-gluon plasma ; transport approach
• 刊名：Nuclear Physics A
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：956
• 期：Complete
• 页码：284-287
• 全文大小：172 K

文摘

We investigate the effects of nuclear mean-field as well as the formation and decay of nuclear clusters on the directed flow 37b9bfda5f5b87985fe4a525d6" title="Click to view the MathML source">v₁$v_1$ in high energy nucleus-nucleus collisions from $\sqrt{s_{NN}}=7.7\text{GeV}$ to 27 GeV incident energies within a transport model. Specifically, we use the JAM transport model in which potentials are implemented based on the framework of the relativistic quantum molecular dynamics. Our approach reproduces the rapidity dependence of directed flow data up to 7b45a99b8a9c10fa7b05b972c192c">$\sqrt{s_{NN}}\approx 8\text{GeV}$ showing the significant importance of mean-field. However, the slopes of dv₁/dy$d{v}_1/dy$ at mid-rapidity are calculated to be positive at $\sqrt{s_{NN}}11.7$ and 19.6 GeV, and become negative above 27 GeV. Thus the result from the JAM hadronic transport model with nuclear mean-field approach is incompatible with the data. Therefore within our approach, we conclude that the excitation function of the directed flow cannot be explained by the hadronic degree of freedom alone.