重离子碰撞中的定向流及其天体物理意义
Directed flow in heavy-ion collisions and its implications for astrophysics
摘要：
在碰撞能量$\sqrt{s_{NN}}$ = 2.7- 39 GeV范围内，对重离子碰撞中质子、反质子和π介子的定向流（$v_1$）进行了分析。模拟已经完成了一个三流体模型采用纯强子状态方程（EoS）和两个版本的EoS与解除禁闭过渡：一阶相变和平滑的交叉过渡。的交叉EoS是明确优选的实验数据在较低的碰撞能量$\sqrt{s_{NN}}\leq$ 20 GeV的描述。然而，在更高的碰撞能量$\sqrt{s_{NN}}\geq$ 20 GeV的纯强子EoS再次成为有利的。这表明在重子密度较高的情况下，夸克-胶子扇区的解除禁闭EoS应该比计算中使用的更硬。后一个发现与天体物理学中讨论的质量可达两个太阳质量的混合恒星的存在是一致的。
英文摘要：
Analysis of directed flow ($v_1$) of protons, antiprotons and pions in heavy-ion collisions is performed in the range of collision energies $\sqrt{s_{NN}}$ = 2.7--39 GeV. Simulations have been done within a three-fluid model employing a purely hadronic equation of state (EoS) and two versions of the EoS with deconfinement transitions: a first-order phase transition and a smooth crossover transition. The crossover EoS is unambiguously preferable for the description of experimental data at lower collision energies $\sqrt{s_{NN}}\leq$ 20 GeV. However, at higher collision energies $\sqrt{s_{NN}}\geq$ 20 GeV the purely hadronic EoS again becomes advantageous. This indicates that the deconfinement EoS in the quark-gluon sector should be stiffer at high baryon densities than those used in the calculation. The latter finding is in agreement with that discussed in astrophysics in connection with existence of hybrid stars with masses up to about two solar masses.
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。
