同位旋守恒对奇异性产生的约束

考虑同位旋守恒约束和奇异夸克的产生压低,研究了高能pp碰撞中的K/π比值,给出了K⁺/π⁺和K^－/π^－与末态产生粒子多重数之间的关系,并提出采用一个近似与参数无关的(K⁺/π⁺)/(K^－/π^－)比值来反映这一过程中同位旋守恒的约束.     

Medium Density and Parton Energy Loss in Gold-Gold Collisions from the Recombination Model

The pion production at mid-rapidity in gold-gold collisions at √s = 200 GeV is investigated by the parton recombination model. The density of the hot medium produced in the collisions and the hard parton energy loss effect are obtained by fitting the experimental data. Both of them are found to have power-law dependence on the number of binary collisions. The implication of such dependence on the nuclear modification factor is discussed.     

π-J/ψ correlation and elliptic flow parameter v2 of charmed mesons at RHIC energy

We study the correlation between the trigger π and the associated J/ψ on near and away sides in Au+Au collisions at √s_NN=200 GeV. In the region of trigger momentum p_t>4 GeV/c, the π spectrum is composed of thermal-shower and shower-shower recombinations in the frame work of the recombination model. We consider the azimuthal anisotropy in the quenched hard parton distribution and then calculate the elliptic flow parameter v₂ of charmed mesons (J/ψ, D⁰ and D_s) for different centralities.     

高能诱发核反应中粒子产生的相对信息熵

在本实验中，引用了一个新的特征量，相对信息熵Ｒ，研究了能量为１４．６，６０，２００ＡＧｅＶ的氧离子和２００ＡＧｅＶ的硫离子诱发核反应的产生粒子多重数分布．在目前的能区中，Ｒ近似地能量无关．Ｒ对快度窗口大小依赖的饱和性，揭示了中心区的熵集中产生．实验结果与Ｌｕｎｄ模型的ＦＲＩＴＩＯＦ模拟计算的预言一致．     

重味展开下的0－重介子束缚态

用瞬时近似下的Bethe-Salpeter(B-S)方程,讨论了0^－重介子束缚态.运用重味质量展开方法求解方程,计算了一级近似下D^±,D⁰,B^±,B⁰介子的质量,与实验数据和其它求解方法的计算结果作了比较.     

Parton Distributions of Pions in the Valon Model

Based on the universality of the parton distributions inside valons, parton distributions of pions are investigated and parametrized from the experimentally given parton distributions of proton within the valon model. The structure function F2(x) is given at fixed scale Q0^2=1 GeV^2. Due to the abundance of the pair numbers of sea quarks at a very small x region, the structure function decreases rapidly for small x to a local minimum. Then from the contribution of the valence quarks, F2(x) increases to a local maximum at x≌0.5.     

A Possible Origin of Power—Law Distribution in Stock Markets

The origin of the power-law distribution in stock markets is discussed from the point of view of self-organized criticality.An analytical expression for the distribution is given from a simple model consideration.We see that power-law increasing or decreasing distribution functions can have the same origin,depending on the values of the parameters.     

Comparative study of the forward and backward methods for calculating jet properties in pp collisions at s~(1/2)=7 TeV

We propose a forward method based on PYTHIA6.4 to study the jet properties in ultra-relativistic pp collisions.In the forward method,the partonic initial states are first generated with PYTHIA6.4 and then hadronized in the Lund string fragmentation model,and finally the hadronic jets are constructed from the created hadrons.Jet properties calculated with the forward method for pp collisions at √s=7 TeV are comparable to those calculated with the usual anti-kt algorithm(backward method)in PYTHIA6.4.The comparison between the backward and forward methods may contribute to the understanding of the partonic origin of jets in the backward method.     

QGP相变中的强子多重数分布与动力学起伏 *

利用Ginzburg Landau模型研究了夸克 强子相变中小间隔内的强子多重数分布 ,将多重数分布与有相同平均多重数的Poisson分布直接比较 ,定义分布的动力学因子dq 及其比值D_q≡d_q/d₁,发现了D_q 间的标度行为 ,该行为可用于判断夸克胶子等离子体是否形成 .同样的方法可用于非相变的过程的研究 .     

重味展开下的0~－重介子束缚态

用瞬时近似下的Ｂｅｔｈｅ－Ｓａｌｐｅｔｅｒ（Ｂ－Ｓ）方程，讨论了０－重介子束缚态．运用重味质量展开方法求解方程，计算了一级近似下Ｄ±，Ｄ０，Ｂ±，Ｂ０介子的质量，与实验数据和其它求解方法的计算结果作了比较．