Quarks in cosmos and in heavy ion collisions

宇宙学和粒子物理学之间存在着基本的联系，这种联系在所有尺度上都得到了很好的确立。特别是，早期宇宙的物理学，重子生成，宇宙核合成等是基于我们对粒子物理学的现代理解。这种认识使早期的宇宙成为研究基础物理学的奇妙实验室，特别是研究理论的真空结构。相反，对高温下基础物理行为的了解，提供了大爆炸后不久发生的事情的信息。更值得注意的是，原则上，QCD尺度上的这些现象可以在RHIC（相对论重离子对撞机），布鲁克海文国家实验室的重离子碰撞中进行实验测试，并在不久的将来在大型强子对撞机（瑞士日内瓦）进行实验，在那里可以实现这种不寻常的环境。该项目的目标是：在温度T、化学势和所谓的θ参数非零的异常环境下，研究QCD作为标准模型的一部分。这一知识为140亿年前宇宙大爆炸后不久在温度T = 170兆电子伏特下发生的事情提供了可靠的信息。对相图（作为这些外部参数的函数）的理解是QCD中最具挑战性的问题之一。这个非零参数的问题在以前的文献中从未被研究过，尽管在大爆炸后不久的QCD相变期间，theta参数很可能是非零的。由于存在θ参数时夸克和反夸克之间相互作用的差异，重子电荷的局部分离可能发生。这种现象可以在RHIC上进行测试。事实上，电荷分离现象已经在我们最近与D. Kharzeev的论文中进行了研究。更重要的是：这种效应已经在RHIC上进行了实验测试。初步结果支持我们的发现。如果得到证实，这将是有史以来第一次在强相互作用中观察到P和CP的破坏。该项目的第二部分是将上述思想应用于天体物理学和宇宙学的需要。

There are fundamental links between cosmology and particle physics, which have been well established at all scales. In particular, the physics of the early Universe, baryogenesis, cosmological nucleosynthesis, etc. is based on our modern understanding of particle physics. This realization has made the early Universe a marvelous laboratory for studying fundamental physics, in particular the vacuum structure of the theory. Conversely, knowledge of the behavior of fundamental physics at high temperature gives information about what happened shortly after the Big Bang. What is more remarkable is the fact that these phenomena at the QCD scale can be, in principle, experimentally tested in heavy ion collisions at RHIC (relativistic heavy ion collider), Brookhaven National Labaratory, and in the nearest future at LHC (Geneva, Switzerland) where such unusual environment can be achieved. The goal of the project is: the study of QCD as part of the standard model in an unusual environment when temperature T, chemical potential and the so-called theta- parameter are non-zero. This knowledge gives a reliable information about what have happened 14 billion years ago soon after the Big Bang at the temperature T = 170 MeV. The understanding of the corresponding phase diagram (as a function of these external parameters) is one of the most challenging problems in QCD. This problem with nonzero theta parameter has never been studied previously in the literature, though it is likely that theta parameter was non-zero during the QCD phase transition few moments after the Big Bang. Due to the differences in interactions between quarks and antiquarks in the presence of the theta parameter the local separation of baryon charges may take place. This phenomenon can be tested at RHIC. In fact, the phenomenon of charge separation has been studied in our recent paper with D. Kharzeev. What is more important: this effect has been experimentally tested at RHIC. Preliminary results support our findings. If confirmed, it would be the first ever observation of the P and CP violation in strong interactions. Second part of the project is the application of the ideas mentioned above for needs of astrophysics and cosmology.