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arXiv · 1601.05390

Origin of the mass splitting of elliptic anisotropy in a multiphase transport model

Hanlin Li·Liang He·Zi-Wei Lin·Denes Molnar·Fuqiang Wang·Wei Xie
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Abstract

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.

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Hanlin Li, Liang He, Zi-Wei Lin, Denes Molnar, Fuqiang Wang, Wei Xie. 2016-05-02. Origin of the mass splitting of elliptic anisotropy in a multiphase transport model. https://doi.org/10.1103/physrevc.93.051901

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