Interplay between core and corona components in high-energy nuclear collisions
Interplay between core and corona components in high-energy nuclear collisions
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DOI：
10.1103/physrevc.105.024905
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发表时间：
2021-08
影响因子：
3.1
通讯作者：
Y. Kanakubo;Y. Tachibana;Tetsufumi Hirano
中科院分区：
文献类型：
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作者：
Y. Kanakubo;Y. Tachibana;Tetsufumi Hirano
我们建立了更新版本的动态核-电晕初始化框架（DCCI2），作为从小到大的碰撞系统和从低到高的横向动量（pT）区域的统一描述。利用DCCI2，我们研究了高能核碰撞中局部平衡和非平衡系统，即核心和日冕组分之间相互作用的影响。以实验多重分布和Ω重子与带电介子的产率比作为输入，我们提取了√s = 7 TeV时p+p碰撞和√sNN = 2.76 TeV时Pb+Pb碰撞的核心和电晕组分的比例。我们发现无论碰撞系统或能量如何，当多重度< dNch/dη > |η|<0.5 ~ 18以上时，核心贡献大于日冕贡献。我们还看到，在p+p碰撞中，只有在0.0-0.95%的多重性类别中，核心的贡献才超过日冕的贡献。值得注意的是，即使在最小偏置Pb+Pb碰撞中，日冕贡献也有较小的增强，低于pT ~ 1 GeV约20%。我们发现低pT下的日冕贡献对Nch下的v2{2}有~ 15- 38%的修正。370. 这在传统的流体动力学分析中提出了一个问题，即低pT软强子仅来自核心部件。最后，我们从基于弦模型的事件发生器中详细分析了弦断裂和纵向膨胀在单位速度横向能量中的作用，这对于流体力学的初始条件至关重要。
We establish the updated version of dynamical core–corona initialization framework (DCCI2) as a unified description from small to large colliding systems and from low to high transverse momentum (pT ) regions. Using DCCI2, we investigate effects of interplay between locally equilibrated and non-equilibrated systems, in other words, core and corona components in high-energy nuclear collisions. Given experimental multiplicity distributions and yield ratios of Ω baryons to charged pions as inputs, we extract the fraction of core and corona components in p+p collisions at √ s = 7 TeV and Pb+Pb collisions at √ sNN = 2.76 TeV. We find core contribution overtakes corona contribution as increasing multiplicity above 〈dNch/dη〉|η|<0.5 ∼ 18 regardless of the collision system or energy. We also see that the core contribution exceeds the corona contribution only in 0.0-0.95% multiplicity class in p+p collisions. Notably, there is a small enhancement of corona contribution with ∼ 20% below pT ∼ 1 GeV even in minimum bias Pb+Pb collisions. We find that the corona contribution at low pT gives ∼ 15-38 % correction on v2{2} at Nch . 370. This raises a problem in conventional hydrodynamic analyses in which low pT soft hadrons originate solely from core components. We finally scrutinize the roles of string fragmentation and the longitudinal expansion in the transverse energy per unit rapidity, which is crucial in initial conditions for hydrodynamics from event generators based on string models.