Origin of the mass splitting of elliptic anisotropy in a multiphase transport model
Origin of the mass splitting of elliptic anisotropy in a multiphase transport model
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DOI：
10.1103/physrevc.93.051901
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发表时间：
2016-01
影响因子：
3.1
通讯作者：
Hanlin Li;Liang He;Zi-Wei Lin;D. Molnár;Fuqiang Wang;W. Xie
中科院分区：
文献类型：
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作者：
Hanlin Li;Liang He;Zi-Wei Lin;D. Molnár;Fuqiang Wang;W. Xie
椭圆各向异性$({v}_{2})$在低横动量下的质量分裂被认为是流体动力集体流动的标志。我们研究了一个多相输运（AMPT）模型，其中${v}_{2}$主要由各向异性逃逸机制产生，而不是流体动力流动性质，并且还观察到质量分裂。我们证明了AMPT在强子化后的${v}_{2}$质量分裂很小（特别是当包括共振衰减时）；质量分裂主要来自强子重散射，尽管它们对整个带电强子${v}_{2}$的贡献很小。这些发现在性质上与结合了流体动力学和强子级联的混合模型相同。我们进一步证明重离子碰撞和小系统碰撞没有质的区别。我们的研究结果表明，${v}_{2}$质量分裂并不是流体动力集体流动的唯一特征，因此不能区分椭圆流主要是由流体动力还是各向异性的部分子逃逸产生的。
The mass splitting of elliptic anisotropy $({v}_{2})$ at low transverse momentum is considered as a hallmark of hydrodynamic collective flow. We investigate a multiphase transport (AMPT) model where the ${v}_{2}$ is mainly generated by an anisotropic escape mechanism, not of the hydrodynamic flow nature, and where mass splitting is also observed. We demonstrate that the ${v}_{2}$ mass splitting in AMPT is small right after hadronization (especially when resonance decays are included); the mass splitting mainly comes from hadronic rescatterings, even though their contribution to the overall charged hadron ${v}_{2}$ is small. These findings are qualitatively the same as those from hybrid models that combine hydrodynamics with a hadron cascade. We further show that there is no qualitative difference between heavy ion collisions and small system collisions. Our results indicate that the ${v}_{2}$ mass splitting is not a unique signature of hydrodynamic collective flow and thus cannot distinguish whether the elliptic flow is generated mainly from hydrodynamics or the anisotropic parton escape.