arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2004.00690nucl-th
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核碰撞中横向动量涨落及其与椭圆流的关联

Transverse momentum fluctuations and their correlation with elliptic flow in nuclear collision

Björn Schenke, Chun Shen, Derek Teaney

摘要:

我们提出了观测$v_0$和$v_0(p_T)$,它量化了在固定多重性的总横向动量的相对波动。我们首先研究了在真实的流体动力学模拟中,将固定多重数动量相关的两粒子关联函数分解为$v_0(p_T^a)$和$v_0(p_T^b)$的乘积。然后,我们提出了计算的$v_0(p_T)$为不同的粒子类型。我们确定的集成$v_0$和以前测得的观测值之间的关系,并比较结果从混合流体动力学为基础的模型的实验数据。体相粘度和初始预平衡阶段对结果的影响被量化。我们发现,$v_0$是强烈相关的初始状态熵每椭圆形面积,$S/A$。利用这一结果,我们解释了如何观察到的椭圆流和横向动量之间的相关性(无论是在模拟和实验)反映$1/A$和椭圆度$\varepsilon_2$在固定的多重性之间的初始状态的相关性。我们认为,系统的实验研究$v_0$,与用于其他$v_n$相同的复杂性,可以大大有助于我们的理解夸克-胶子等离子体的性质。

英文摘要:

We propose observables $v_0$ and $v_0(p_T)$ which quantify the relative fluctuations in the total transverse momentum at fixed multiplicity. We first study the factorization of the fixed multiplicity momentum dependent two particle correlation function into a product of $v_0(p_T^a)$ and $v_0(p_T^b)$ within realistic hydrodynamic simulations. Then we present computations of $v_0(p_T)$ for different particle types. We determine the relation between the integrated $v_0$ and previously measured observables, and compare results from a hybrid hydrodynamics based model to experimental data. The effects of bulk viscosity and an initial pre-equilibrium stage on the results are quantified. We find that $v_0$ is strongly correlated with the initial state entropy per elliptic area, $S/A$. Using this result, we explain how the observed correlations between the elliptic flow and the transverse momentum (both in simulations and experiment) reflect the initial state correlations between $1/A$ and ellipticity $\varepsilon_2$ at fixed multiplicity. We argue that the systematic experimental study of $v_0$, with the same sophistication as used for the other $v_n$, can contribute significantly to our understanding of quark gluon plasma properties.

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