arXiv 1702.011032017-02-03hep-phhep-exnucl-exnucl-th

重离子碰撞中粒子多重性熵产生率的上界

On the upper bound of entropy production rate from particle multiplicity in heavy ion collisions

Mateusz Ploskon, Martin Veselsky

摘要：

我们提供了一个简单的推导过程，在重离子碰撞中，粒子的产生与熵产生率成正比。我们发现粒子的产生只取决于质心碰撞能量$\sqrt{s_{\rm NN}}$的幂和有效相空间/体积（例如，碰撞的几何形状近似于参与碰撞的核子数$N_{\rm part}$）.我们发现，在低能量下，每个参与核子对的粒子的赝快度密度与$\sqrt{s_{\rm NN}}$成线性比例，而在高能量下与$\sqrt{s_{\rm NN}}^{1/3}$成线性比例。$\sqrt{s_{\rm NN}}^{1/3}$区域与亚核子自由度和夸克-胶子等离子体（QGP）的产生直接相关。这幅图解释了实验观察到的带电粒子的每个核子对的赝快度-密度分布的形状在大的碰撞能量跨度上不依赖于$\sqrt{s_{\rm NN}}$。我们提供了一个缩放的解释，并将其与熵产生的每单位时间的最大速率。最后，我们对强子-部分子相变进行了评述。特别是，我们的考虑表明，每$N_{\rm part}/2$产生的粒子的伪快速密度大于约1（不包括来自喷流碎裂的粒子）是QGP形成的标志。

英文摘要：

We provide a simple derivation for particle production in heavy-ion collisions that is proportional to the rate of entropy production. We find that the particle production depends only on the power of the centre-of-mass collision energy $\sqrt{s_{\rm NN}}$ and the effective phase-space/volume (e.g. geometry of the collision approximated by the number of nucleons participating in the collision $N_{\rm part}$). We show that at low-energies the pseudo-rapidity density of particles per participating nucleon pair scales linearly with $\sqrt{s_{\rm NN}}$ while at high-energies with $\sqrt{s_{\rm NN}}^{1/3}$. The $\sqrt{s_{\rm NN}}^{1/3}$ region is directly related to sub-nucleon degrees of freedom and creation of a quark-gluon plasma (QGP). This picture explains experimental observation that the shape of the distributions of pseudorapidity-density per nucleon pair of charged particles does not depend on $\sqrt{s_{\rm NN}}$ over a large span of collision energies. We provide an explanation of the scaling and connect it with the maximum rate per unit time of entropy production. We conclude with remarks on the hadron-parton phase transition. In particular, our considerations suggest that the pseudo-rapitidy density of the produced particles per $N_{\rm part}/2$ larger than approximately 1 (excluding particles from jet fragmentation) is a signature of a QGP formation.

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。

摘要：

英文摘要：

相关论文