Stable solutions for qq bound states with a regularized Breit potential

The Breit interaction contains singular terms which may lead to an instability in quark-antiquark bound state calculations. We regularize the Breit interaction by multiplying the singular terms in momentum space by the form factor μ^2/（q^2＋μ^2） such that the interaction is not singular at the origin and the intermediate-and long-range parts of the interaction remain unchanged. The singular terms in the Breit potential find their stable contributions in the calculations after being multiplied by the form factor with different powers. Such a regularized Breit potential with a linear and a relativistically corrected confining potential are applied to the study of qq^- bound states. The spectra for most familiar mesons are consistently obtained and agree well with the experimental data.     

对光滑粒子流体动力学模型π源的视像分析

∈利用光滑粒子流体动力学模型，研究了NN=200 GeV Au+Au碰撞产生的介子发射源的视像结果。 碰撞后的演化图显示， 系统在演化过程中呈现出明显的非均匀性颗粒集团分布。 这种发射源所得到的视像分析结果表明， 即使在相同的碰撞参数下， 不同事件的相对发射源函数也会存在差异。 这种差异在大碰撞参数下表现得尤为明显。 We investigate the imaging of pion emitting source produced in NN=200 GeV Au+Au collisions with NeXSPheRIO model. The pictures of the system evolution show that there is obvious inhomogeneous structure of granular lumps. The results of imaging analysis indicate that the relative source functions for the various events of the granular sources are different even though the events are with the same impact parameter. This difference is more evident for the events with large impact parameter.     

Two-pion interferometry for viscous hydrodynamic sources

The space-time evolution of the (1+1)-dimensional viscous hydrodynamics with an initial quark-gluon plasma (QGP) produced in ultrarelativistic heavy ion collisions is studied numerically. The particle-emitting sources undergo a crossover transition from the QGP to hadronic gas. We take into account a usual shear viscosity for the strongly coupled QGP as well as the bulk viscosity which increases significantly in the crossover region. The two-pion Hanbury-Brown-Twiss (HBT) interferometry for the viscous hydrodynamic sources is performed. The HBT analyses indicate that the viscosity effect on the two-pion HBT results is small if only the shear viscosity is taken into consideration in the calculations. The bulk viscosity leads to a larger transverse freeze-out configuration of the pion-emitting sources, and thus increases the transverse HBT radii. The results of the longitudinal HBT radius for the source with Bjorken longitudinal scaling are consistent with the experimental data.     

Two-pion interferometry for a partially coherent evolution source

We give the formulas of two-pion Hanbury-Brown-Twiss (HBT) correlation function for a partially coherent evolution pion-emitting source, using quantum probability amplitudes in a path-integral formalism. The multiple scattering of the particles in the source is taken into consideration based on Glauber scattering theory. Two-pion interferometry with effects of the multiple scattering and source collective expansion is examined for a partially coherent source of hadronic gas with a finite baryon density and evolving hydrodynamically. We do not find observable effect of either the multiple scattering or the source collective expansion on HBT chaotic parameter.     

高能重离子碰撞中的横向非对称流

对末态粒子方位角分布的研究可以获得反应中有关横向非对称流的信息.研究了碰撞中侧向流与椭圆流间的方位角关联,给出了一种定量测量反应中椭圆流大小的方法,该方法的计算结果可以有效地消除估计反应平面离散的影响.     

RHIC能区Au+Au碰撞中集合径向流的研究

利用相对论量子分子动力学模型RQMD,对RHIC能区s=200A GeV Au+Au碰撞的集体膨胀效应进行了研究,对散射粒子的横质量谱进行了分析.研究表明,在RHIC能区的重离子反应中存在有强的集合径向流.对单粒子谱的拟合结果给出Au+Au的源冻结温度为160MeV,平均径向流速度为0.6c.     

高能重离子碰撞中末态粒子分布的非对称性

对Bevalac1.2A GeV Au+Au碰撞实验,根据以流方向为z轴的质心坐标系中末态粒子方位角分布的非对称性为极小的条件,确定了事件中五种质量范围(A=1,2,3,4,5-8)末态粒子的集合侧向流流角.在以流方向为z轴的质心坐标系中研究了不同质量末态粒子极角分布,结果表明质量越大的粒子在流方向分布得越集中,侧向流的“流”值越大.     

2π干涉学分析的源空间参数

本文通过直接比较相应于不同密度分布源的关联函数,指出源的平均半径是2π干涉学分析中描述源空间线度的好物理量.比较不同关联函数分析获得的源空间参量时,选取源的平均半径为判别标准不仅优于Bartke和Kowalski提出的均方根半径,也优于Goldhaber等人提出的GGLP因子.对不同碰撞实验的2π干涉学结果的系统分析表明,使用我们提出的比较标准给出的结果更加合理.     

HBT参数对π源空间分布的敏感性研究(英文)

利用理想高斯源的两粒子关联函数，对单高斯源和双高斯源的两π介子HBT关联效应进行了研究，得出了相应的半径参数和A参数．结果表明，半径参数主要取决于高能重离子碰撞中多数π介子产生的中间区域；对产生π介子的边缘区域的空间分布形状不敏感．在边缘区域内产生的π介子主要影响A参数的变化．π介子源空间分布的非高斯形是导致λ参数减少的一个重要因素．The HBT radius parameters and the HBT λ-parameters of single Gaussian source and double Gaussian source are investigated by using two-pion correlation function in HBT intensity interferometry. It is indicated that the radius parameter is insensitive to the spatial shape of the edge zone of source and is mainly affected by the size of the central zone of pions emitted in high energy heavy-ion collisions. The pions produced at the edge of source influence the λ parameter. The non-Gaus...     

高温下夸克场真空图中的红外发散

用热传播子的实时形式对高温条件下夸克(忽略质量)场三圈真空图进行了详细地计算,找出了其中和费米–狄拉克统计因子有关的红外发散积分的类型,并对这种发散积分进行了正规化,进一步把真空图中的红外发散全部孤立出来了.