Correlations among elliptic flow parameter, impact parameter, and multiplicity
Correlations among elliptic flow parameter, impact parameter, and multiplicity
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DOI：
10.1140/epja/i2010-11013-2
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发表时间：
2010-09
期刊：
影响因子：
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通讯作者：
D. Zhou;Yun Cheng;Yu-Liang Yan;B. Dong;B. Sa;Laszlo P. Csernai
中科院分区：
文献类型：
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作者：
D. Zhou;Yun Cheng;Yu-Liang Yan;B. Dong;B. Sa;Laszlo P. Csernai
考虑多重性起伏，研究了动量空间中单个事件带电粒子多重性方位分布的傅里叶展开式中的椭圆流参数v2。采用带熔炼的多相输运模型，研究了可测变量v2、带电倍数和冲击参数之间的相关性。结果表明，载荷数与冲击参数呈负相关。这种相关性导致了v2的峰结构作为RHIC实验中测量的参与核子数（带电倍数，冲击参数）的函数。结果表明，事件平均计算得到的v2比粒子平均计算得到的v2大20%左右，因此在理论计算中应采用事件平均计算。
The elliptic flow parameter, v2, in the Fourier expansion of the event-by-event charged-particle multiplicity azimuthal distribution in the momentum space is studied by taking into account the multiplicity fluctuations. The correlations among measurable variables of v2, charged multiplicity, and impact parameter are investigated using a multiple phase transport model with string melting. It turned out that the charged multiplicity and impact parameter are negatively correlated. This correlation results in the peak structure in v2as a function of the participant nucleon number (charged multiplicity, impact parameter) measured in RHIC experiments. It is suggested that v2calculated in the event-wise average is about 20% larger than in the particle-wise average, so event-wise average should be used in the theoretical calculations.