Left-right splitting of elliptic flow due to directed flow in heavy ion collisions
Left-right splitting of elliptic flow due to directed flow in heavy ion collisions
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DOI：
10.1103/physrevc.106.054910
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发表时间：
2021-09
影响因子：
3.1
通讯作者：
Chao Zhang;Zi-Wei Lin
中科院分区：
文献类型：
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作者：
Chao Zhang;Zi-Wei Lin
最近，在非中心相对论性重离子碰撞中，由于全局涡度的存在，提出了有限速度下椭圆流v2的分裂。在本研究中，我们发现椭圆流在有限速度下的左右分裂（即在冲击参数轴的相对两侧）是由非零定向流动v 1引起的，其分裂幅度≈8 v 1(1−3 v 2) / (3 π)。我们还使用自动包含涡度场和流动波动的多相输运模型来证实v 2分裂。此外，我们发现，对于原始v2和v1（即，在应用事件平面分辨率之前），相对于一阶或二阶事件平面测量了v2分裂的分析期望。由于v2分裂主要是由v1驱动的，它在零横向动量（p0）时消失，其大小和符号可能与p0、中心性、碰撞能量和强子种类有非显著的依赖关系。
Recently the splitting of elliptic flow v 2 at finite rapidities has been proposed as a result of the global vorticity in non-central relativistic heavy ion collisions. In this study, we find that this left-right (i.e., on opposite sides of the impact parameter axis) splitting of the elliptic flow at finite rapidities is a result of the non-zero directed flow v 1 , with the splitting magnitude ≈ 8 v 1 (1 − 3 v 2 ) / (3 π ). We also use a multi-phase transport model, which automatically includes the vorticity field and flow fluctuations, to confirm the v 2 splitting. In addition, we find that the analytical expectations for the v 2 splitting work for the raw v 2 and v 1 (i.e., before event plane resolutions are applied) measured relative to either the first- or second-order event plane. Since the v 2 splitting is mostly driven by v 1 , it vanishes at zero transverse momentum ( p T ), and its magnitude and sign may have non-trivial dependencies on p T , centrality, collision energy, and hadron species.