Probing QCD phase structure using baryon multiplicity distribution
Probing QCD phase structure using baryon multiplicity distribution
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DOI：
10.1093/ptep/ptw013
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发表时间：
2013-05
影响因子：
3.5
通讯作者：
A. Nakamura;K. Nagata
中科院分区：
文献类型：
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作者：
A. Nakamura;K. Nagata
提出了一种仅利用CP对称从净重子、净电荷和净奇异度等净数分布构造量子色动力学正则配分函数的新方法。为了证明该方法，我们将其应用于最近在相对论重离子对撞机上测量的净质子数分布Pn。我们证明了μ/T和正则配分函数Zn都是由CP不变性Zn = Z−n决定的。将净质子分布的μ/T与热统计模型的μ/T进行比较，我们发现在很宽的束流能量范围内，μ/T是非常一致的。我们构造了一个大正则配分函数Z (μ，T) = n Zn(T)ξ n，研究了RHIC数据的矩和李-杨零，并讨论了QCD中相变线的可能区域。这是首次获得RHIC数据的Lee-Yang零图，这有助于我们看到大净质子数据对探索QCD相图的贡献。我们还通过晶格QCD模拟计算了Zn，并发现了夸克-胶子等离子体相中Roberge - Weiss相变的明显迹象。该方法不依赖泰勒展开式，因为泰勒展开式会阻止我们得到大的μ/T。
We propose a new method to construct canonical partition functions of quantum chromodynamics (QCD) from net number distributions, such as net baryon, net charge, and net strangeness, by using only the CP symmetry. To demonstrate the method, we apply it to the net-proton number distribution Pn recently measured at the Relativistic Heavy Ion Collider. We show that both μ/T and the canonical partition functions Zn are determined by using the CP invariance Zn = Z−n. Comparing μ/T obtained from the present analysis for the net-proton distribution and that obtained from a thermal statistical model, we find remarkable agreement for a wide range of beam energies. Constructing a grand canonical partition function Z (μ,T ) = n Zn(T )ξ n ,w e study moments and Lee–Yang zeros for RHIC data, and discuss the possible regions of a phasetransition line in QCD. This is the first Lee–Yang zero diagram obtained for RHIC data, which helps us to see contributions of large net-proton data for exploring the QCD phase diagram. We also calculate Zn by the lattice QCD simulations, and find a clear indication of a Roberge– Weiss phase transition in the quark–gluon plasma phase. The method does not rely on Taylor expansions, which prevent us going to large μ/T.