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arXiv 2408.07563nucl-thnucl-ex
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高重子密度区中介子的反流现象

Anti-flow of Mesons in the High Baryon Density Region

Zuo-Wen Liu, Shusu Shi

AI总结:

本文利用 JAM 输运模型研究高重子密度区 Au+Au 碰撞中介子定向流的反流现象,发现旁观者遮蔽效应是低横动量下介子反流产生的关键机制。

摘要:

E895 和 STAR 实验表明,在 Au + Au 碰撞中,当质心能量为 $\sqrt{s_{NN}} = 3.0 - 3.9$ GeV 时,介子相对于快度的定向流斜率($dv_1/dy|_{y=0}$)在低横动量($p_T$)区域($p_T < 0.8$ GeV/$c$)为负值。利用输运模型 JAM,我们在与 E895 和 STAR 实验相同的能量下,研究了 Au + Au 碰撞中 $π^{\pm}$、$K^{\pm}$ 和 $K^0$ 的定向流随快度、$p_T$ 和碰撞能量的变化。我们发现 JAM 模型能够定性重现 E895 实验中观测到的 $K^0_S$ 反流现象。通过分析 π 介子和 K 介子的 $v_1$ 斜率随 $p_T$ 窗口的变化,揭示了 $v_1$ 斜率对 $p_T$ 的强烈依赖性。在低 $p_T$ 区域($p_T < 0.8$ GeV/$c$)观测到负的 $v_1$ 斜率,而在较高 $p_T$ 区域则呈现正的斜率。我们发现,来自旁观者的遮蔽效应对于在高重子密度区低 $p_T$ 下产生介子反流至关重要。

英文摘要:

The E895 and STAR experiments demonstrate that the slopes of directed flow with respect to rapidity ($dv_1/dy|_{y=0}$) of mesons are negative in the low transverse momentum ($p_T$) region, $p_T < 0.8$ GeV/$c$, in Au + Au collisions at $\sqrt{s_{NN}} = 3.0 - 3.9$ GeV. Using the transport model JAM, we investigate the directed flow of $π^{\pm}$, $K^{\pm}$, and $K^0$ as functions of rapidity, $p_T$, and collision energy in Au + Au collisions at the same energies as those in the E895 and STAR experiments. We find that the JAM model can qualitatively reproduce the anti-flow of $K^0_S$ observed in the E895 experiment. The $v_1$ slopes of pions and kaons are analyzed as functions of the $p_T$ window, revealing a strong $p_T$ dependence of the $v_1$ slopes. Negative $v_1$ slopes are observed in the low $p_T$ region, $p_T < 0.8$ GeV/$c$, while positive slopes are shown in the higher $p_T$ region. We find that the shadowing effect from spectators is crucial in generating the anti-flow of mesons at low $p_T$ in the high baryon density region.

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。

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