相对论重离子碰撞中多粲夸克重子的产生

发布时间：2018-06-07 11:33

本文选题：相对论重离子碰撞 + 夸克胶子等离子体　；参考：《清华大学》2016年博士论文

【摘要】：本文研究了相对论重离子碰撞中,由三个粲味夸克组成的重子?++ccc以及两个粲味夸克与一个轻夸克组成的重子Ξ+cc的产生。首先,我们在势模型的框架下,研究了三夸克束缚态的运动方程,通过超球坐标的方法将三维空间的三体运动方程转换为九维空间的单体运动方程,求解了?++ccc的波函数、质量、熔解温度等基本特征;针对含有轻夸克组份的Ξ+cc,我们将其波函数按照超球谐函数展开,并对其质量和波函数进行了相对论修正。其次,基于求解三体演化方程得到的多粲夸克重子基态波函数,我们计算了相应的Wigner函数并将其参数化。再利用夸克并合模型计算了?++ccc和Ξ+cc的产额与动量分布。在研究手段上,我们求解三夸克束缚态运动方程得到重子波函数作为Wigner函数的输入,这与传统的的夸克并合模型相比更加自然适用性也更广。我们发现,LHC中碰撞能量√sN N=2.76 T eV时,Pb+Pb碰撞中一次有效p+p碰撞?++ccc和Ξ+cc的产生截面就比相同能量下p+p碰撞截面分别至少高两个和一个数量级,这意味着在LHC的核碰撞中极有可能发现?++ccc和Ξ+cc,是夸克模型正确性的一个重要证明。如果在实验上被观测到,?++ccc和Ξ+cc不仅是夸克模型所预言的粲味重子家族的新成员,也将是一种新的干净且独特的夸克胶子等离子形成的信号探针粒子。
[Abstract]:In the relativistic heavy ion collisions, the production of baryon-ccc, which consists of three charmed quarks and two charmed quarks and one light quark-cc, is studied. Firstly, in the framework of potential model, we study the equations of motion of three-quark bound states. By using the method of hyperspherical coordinates, we transform the three-body motion equations in three-dimensional space into the single motion equations in nine-dimensional space, and solve the wave function of? ccc. Mass, melting temperature and so on. For the cc-containing light quark component, the wave function is expanded according to the hyperspherical harmonic function, and its mass and wave function are modified by relativistic method. Secondly, based on the ground state wave function of the multi-charm quark baryon obtained by solving the three-body evolution equation, we calculate the corresponding Wigner function and parameterize it. The yield and momentum distributions of? ccc and-cc are calculated by using the quark combination model. On the other hand, we obtain baryon wave function as the input of Wigner function by solving the three-quark bound state equation of motion, which is more natural and applicable than the traditional quark combination model. We find that the generation cross sections of ccc and cc are at least two and one orders of magnitude higher than those of p-p collision at the same energy, respectively, when the collision energy in the LHC is 2. 76 T EV, and the effective p p collision in the Pb Pb collision is at least two and one orders of magnitude higher than that of the p p collision cross section at the same energy. This means that it is very likely to be discovered in LHC nuclear collisions? ccc and cc-which are an important proof of the correctness of quark model. If it is observed experimentally that ccc and cc are not only new members of the charm baryon family predicted by the quark model, but also a new and unique signal probe particle formed by quark gluon plasma.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O571.6;O572.2

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