Search for the Critical Point of Quantum Chromodynamics (QCD)

相对论性核-核碰撞产生了一个短暂的融合高能量密度物质的复合系统（哈格多恩火球），其性质反映在嵌入实验观察到的最终状态中的大量可观察物理学中。最近在非微扰格子量子色动力学（QCD）中的一个突破导致了关于QCD相图中的部分子-强子共存线的详细预言，特别是在（，T-图中似乎显示出一个临界点。此外（有待进一步的晶格技术改进），这一点似乎出现在间隔300（B（450 MeV），对应于2002年结束的CERN SPS实验（7（10 GeV）的较低能量域。在这个能量区间的新的兴趣，使我们建议修订相应的NA 49数据（铅+铅在各种SPS能量），要么没有以前分析，或尚未在其最终形式。临界点（和发生在（&gt;（crit））的一阶部分子强子相变的物理学表明了逐事件的涨落分析，例如逐事件的横动量< pT >，π介子和K介子多重数密度，以及非奇异粒子与奇异粒子产生的几个比率，如逐事件的K/（和K/p比率。NA 49（运行到2002年）的大接受度和高强子分辨能力使这些数据分析特别有希望。

Relativistic nucleus-nucleus collisions create a short-lived compound system (the Hagedorn fireball) of fused, high energy density matter, the properties of which being reflected in a multitude of physics observable as imbedded in the experimentally observed final state. A recent breakthrough in non-perturbative lattice Quantum Chrome-dynamics (QCD) has led to detailed predictions concerning the parton-hadron coexistence line in the QCD phase diagram which, in particular, seems to exhibit a critical point in the (, T-diagram. Moreover (pending further lattice technical refinement) this point appears to occur in the interval 300 ( (B ( 450 MeV that corresponds to the lower energy domain of the CERN SPS experiments (7 ( ( 10 GeV) that ended in 2002. The renewed interest in this energy interval leads us to propose revisting the corresponding NA49 data (Pb+Pb at various SPS energies) which either have not been previously analyzed, or are not yet in their final form. The physics of the critical point (and the first order parton hadron phase transition occurring at ( > (crit) suggest event by event fluctuation analysis, e.g. of the eventwise transverse momentum < pT >, the pion and kaon multiplicity density, as well as several ratios of nonstrange to strange particle production like the eventwise K/( and K/p ratios. The large acceptance and the high hadron discrimination power of NA49 (which ran until 2002) make these data analysis particularly promising.