arXiv 1902.062542019-02nucl-th

LHC核-核碰撞中夸克质量对重夸克观测量的影响

Impact of Glasma on heavy quark observables in nucleus-nucleus collisions at LHC

Yifeng Sun, Gabriele Coci, Santosh Kumar Das, Salvatore Plumari, Marco Ruggieri, Vincenzo Greco

备注：: 7 pages, 4 figures
DOI：: 10.1016/j.physletb.2019.134933

摘要：

在相对论重离子碰撞的热平衡前阶段，在$τ_0 \simeq 0.1 \, \rm fm/c$附近产生一个强的准经典横胶子场，并与它们的纵胶子场一起按照经典Yang-Mills（CYM）方程演化.最近，它已被证明，这些领域引起的扩散的魅力夸克在动量空间中导致倾斜的频谱没有显着的阻力。我们发现，在LHC的核-核碰撞中，这种新的动力学的魅力夸克导致的初始增强的核修改因子（$R_{AA}$）在$p_T$大于2 GeV的$/c$与标准的传说。此外，相同的动力学导致更大的最终椭圆流（$v_2$），从而导致$R_{AA}$和$v_2$之间的关系非常接近实验测量。我们的研究还表明，这样一个初始的预热阶段是不可能被描述的标准阻力和扩散动力学，因为即使一个调整这样的系数，以重现相同的$R_{AA}(p_T)$，这将意味着一个显着较小的$v_2$。

英文摘要：

In the pre-thermal equilibrium stage of relativistic heavy-ion collisions, a strong quasi-classical transverse gluon field emerges at about $τ_0 \simeq 0.1 \, \rm fm/c$ and evolves together with their longitudinal counterparts according to the classical Yang-Mills (CYM) equations. Recently it has been shown that these fields induce a diffusion of charm quarks in momentum space resulting in a tilt of their spectrum without a significant drag. We find that in nucleus-nucleus collisions at LHC such a novel dynamics of charm quarks leads to an initial enhancement of the nuclear modification factor ($R_{AA}$) at $p_T$ larger than 2 GeV$/c$ contrary to the standard lore. Moreover, the same dynamics leads to a larger final elliptic flow ($v_2$) inducing a relation between $R_{AA}$ and $v_2$ that is quite close to the experimental measurements. Our study also shows that such an initial pre-thermal stage is unlikely to be described in terms of a standard drag and diffusion dynamics, because even if one tune such coefficients to reproduce the same $R_{AA}(p_T)$ this would imply a significantly smaller $v_2$.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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