Large SU（3） Symmetry Breaking in J／ψ→BB Decays

Large SU(3) symmetry breaking effects in J/ψ→BB decay processes are discussed using the Mark I,Mark II,DM2 and the recent data from BES Collaboration.     

Thied—Order Approximation of 0^＋＋ Glueball Mass and Wavefunction of （2＋1）—Dimensional SU（3） Lattice Gauge Theory

The random phase approximation is applied to the coupled-cluster expansions of lattice gauge theory (LGT) Using this method,wavefuctions are approximated by linear combination of graplh consisting of only one connected wilson loop.We study the excited state energy and wavelunction in (2 1)-D SU(3) LGT up to the thired order,The glueball mass shows a good scaling behavior.     

Vector and Spinor Decomposition of SU（2） Gauge Potential, Their Equivalence, and Knot Structure in SU（2） Chern-Simons Theory

In this paper, spinor and vector decompositions of SU（2） gauge potential are presented and their equivalence is constructed using a simply proposal. We also obtain the action of Faddeev nonlinear 0（3） sigma model from the SU（2） mass/ve gauge field theory, which is proposed according to the gauge invariant principle. At last, the knot structure in SU（2） Chern-Simons filed theory is discussed in terms of the Φ-mapping topological current theory, The topological charge of the knot is characterized by the Hopf indices and the Brouwer degrees of Φ-mapping.     

利用SU（2）_（q，s）量子代数的两参数变形振子实现讨论SU（2）_（q，s）相干态

利用ＳＵ（２）ｑ，ｓ量子代数的两参数变形振子实现构造出与Ｐｅｒｅｌｏｍｏｖ相干态形式不同的ＳＵ（２）ｑ，ｓ相干态．证明了ＳＵ（２）ｑ，ｓ，量子代数的表示基是正交的，并讨论了它的相干态的归一性和完备性．指出ＳＵ（２）ｑ，ｓ相干态的相干性受参数ｑ，ｓ的影响，它比单参数变形ＳＵ（２）ｑ相干态更具一般性．     

Energy Level Statistics of SO（5） Limit of Super-symmetry U（6/4） in Interacting Boson-Fermion Model

We study the energy level statistics of the SO（5） limit of super-symmetry U（6/4） in odd-A nucleus using the interacting boson-fermion model. The nearest neighbor spacing distribution （NSD） and the spectral rigidity （Δ3） are investigated, and the factors that affect the properties of level statistics are also discussed. The results show that the boson number N is a dominant factor. If N is small, both the interaction strengths of subgroups SO^B（5） and SO^BF （5） and the spin play important roles in the energy level statistics, however, along with the increase of N, the statistics distribution would tend to be in Poisson form.     

格点变模SU（2）－Higgs模型的解析计算

在四维空间对格点ＳＵ（２）－Ｈｉｇｇｓ模型的序参量Ｅｐ＝〈ｔｒＵｐ〉〉用累积展开计算到四级近似．Ｈｉｇｇｓ场为基础表示．发展了定双变分参数的办法．得到的相图与蒙特卡罗结果有好的符合．     

SU（3） Simple Group Model and New Z＇ Properties in Future Linear Colliders

In the SU（3） simple group model, the new neutral gauge boson Z＇ couples to pairs of SM fermions with couplings fixed in terms of the SM gauge couplings and depending only on the choice of the fermion embedding. In this paper, we calculate the contributions of this new particle to the processes e^＋e^-→l^＋l^-, bb^-, and cc^- and study the possibility of detecting this new particle via these processes in the future high-energy linear e^＋e^- collider（LC） experiments with √s= 500 GeV and ￡int= 340 fb^-1. We find that the new gauge boson Z＇ is most sensitive to the process e^＋e^-→b^＋b^-. As long as Mz,≤2 TeV , the absolute values of the relative correction parameter are larger than 5%. We calculate the forward-backward asymmetries and left-right asymmetries for the process e^＋e^-→c^＋c^-, with both the universal and anomaly-free fermion embeddings. Bounds on Z＇ masses are also estimated within 95% confidence level.     

正则形式的SU（N）规范理论的约束关联动力学（I）关联Green函数的运动方程

在关联动力学思想框架内，运用生成泛函技术，在时性规范和正则量子化形式下，建立起ＳＵ（Ｎ）规范理论的约束关联动力学的完整体系，得到了关联Ｇｒｅｅｎ函数的运动方程组系列．     

高能物理学面临的两大难题

 一、物质结构历史简述大家知道,物质结构的研究已从早先的原子层次深入到夸克和轻子这一新层次。１９１１年,卢瑟福实验证实了原子中原子核的存在并发现了质子,１９３２年查德威克的实验发现了中子．中子的发现开创了人类认识物质结构从原子核进到质子、中子这一层次．海森伯和伊凡宁柯立即提出了原子核由质子和中子组成的假说．不久,这一假说获得验证并得到了有关原子核的正确认识．原子是由原子核和绕核运动的电子组成的,而原子核由质子和中子通过强相互作用结合而成．这样,随着核物理的发展,人类对物质结构的认识进入到基本粒子这一层次,即认识到自然界万物是由质子、中子、电子这些基本粒子构成的．     

Topological Quantization of Instantons in SU（2） Yang-Mills Theory

By decomposing SU（2） gauge potential in four-dimensional Euclidean SU（2） Yang-Mills theory in a new way, we find that the instanton number related to the isospin defects of a doublet order parameter can be topologically quantized by the Hopf index and Brouwer degree. It is also shown that the instanton number is just the sum of the topological charges of the isospin defects in the non-trivial sector of Yang-Mills theory.     

Isospin and mixed symmetry structure in ~(26)Mg

The isospin excitation states and electromagnetic transitions of the ²⁶Mg nucleus are studied with the isospin-dependent interacting boson model (IBM-3). The mixed symmetry states at low spin and the main components of the wave function for some states are also analyzed. The results show good agreement with the available experimental data. From the IBM-3 Hamiltonian expressed in Casimir operator form, the ²⁶Mg is also proved to be a transition nuclei from U(5) to SU(3).     

强子作为非拓扑孤粒子的SU（5）大统—模型（Ⅰ）

提出一种新的包含三代已知轻子与夸克的ＳＵ（５）大统—模型．按本模型，强子可看作由夸克形成的非拓扑孤粒子；轻子与夸克本质上是相同的，它们之间的差别是由对称性自发破缺造成的；在强子内部，夸克质量很小，其性质与已知夸克相同；在强子外部，夸克的性质与已知轻子相同，只是质量很重，并将很快衰变．本文除了定义严格守恒的电荷Ｑ０、费米子数Ｆ０外，还在孤粒子内部定义了近似守恒的内色荷、内电荷、内费米子数．已知ＳＵ（５）大统—模型的（Ｌ－Ｂ）守恒相应于本模型的Ｆ０守恒。     

LHC实验中超对称粒子及暗物质的寻找

1.引言英国诗人艾略特(T.S.Eliot)在《四个四重奏》中写到:"我们叫作开始的往往就是结束,而宣告结束也就是着手开始。终点是我们出发的地方。"这不禁让我们想到古希腊神话里的一个怪物Uroboros——一条吞吃自己尾巴的蛇。其实,宇宙何尝不像一个Uroboros呢?——时空的起点和终点咬在了一起(图1)。     

中间玻色子及其发现后的十年

 十年前,1983年1月25日,西欧中心（CERN）向全世界宣布了一项重大发现:该中心的UA1和UA2两个实验组在正-反质子对撞机上发现了带电中间玻色子W⁺和W^-,这一捷报引起的科学界的激动尚未平复,两个实验组又分别于同年6月和7月宣告了W粒子的电中性伙伴--中性中间玻色子Z°的发现。这两种传递弱相互作用的媒介子的发现,直接有力地证实了电-弱统一理论的正确性。当时,西欧中心所长索培尔评价说:“这是三十五年前发明晶体管以来物理学领域中最重要的发现”。这项举世瞩目的物理成果,马上赢得了科学界的最高荣誉。两位领头人,一位是促使西欧中心将超级质子同步加速器（SPS）改建成质子-反质子对撞机,并负责这个反质子课题的意大利物理学家卢比亚,一位是发明随机冷却技术,从而使反质于便于处理的荷兰物理学家范德梅尔,荣获1984年诺贝尔物理学奖。     

Analytical Solution for the SU（2） Hedgehog Skyrmion and Static Properties of Nucleons

An analytical solution for symmetric Skyrmion is proposed for the SU（2） Skyrme model, which takes the form of the hybrid form of a kink-like solution, given by the instanton method. The static properties of nucleons is then computed within the framework of collective quantization of the Skyrme model, in a good agreement with that given by the exact numeric solution. The comparisons with the previous results as well as the experimental values are also presented.     

标准模型及其扩充

 不论是刀耕火种的远古,还是星际遨游的现代,人类总是以无限的激情和不尽的欲望来从事所有可能的智力活动。而智力活动的方式,却是人类根据不同时期所能感悟到的物质的尺度而刻意选取的。因此,物质的尺度可以用来衡量人类在各个时期的智力水平。     

富勒烯衍生物C60（CF3）n（n=2，4，6，10）几何结构和电子性质变化规律的密度泛函研究

采用密度泛函理论中的广义梯度近似对C₆₀（CF₃）_n （n=2,4,6,10）几何结构和电子性质的变化规律进行了计算研究.发现在C₆₀（CF₃）₄可能稳定存在的三种同分异构体中,具有p p p加成方式的衍生物热力学性质最为稳定;在C₆₀（CF₃）₆可能稳定存在的三种同分异构体中,具有p p p m p加成方式的衍生物热力学性质最为稳定.对C₆₀（CF₃）₂,C₆₀（CF₃）₄,C₆₀（CF₃）₆和C₆₀（CF₃）₁₀四种加成衍生物的几何结构分析可知：随着CF₃加成个数的增加,C₆₀中的C—C平均键长逐渐变大,笼子与CF₃之间连接键C_C60—C_CF3逐渐变大.对它们的电子结构分析可知,随着CF₃加成数目的增多,反应热几乎是线性增加.而C₆₀（CF₃）_n（n=2,4,6,10）分子的平均反应热在n=6处为极大值,说明C₆₀（CF₃）₆应该是最容易得到的加成产物.由Mulliken电荷可知,加成的CF₃个数越多,CF₃与笼子的相互作用也就越强,每个CF₃转移到笼子上电荷数也就越多.C₆₀（CF₃）_n的自旋聚居数分布表明它们均为闭壳层结构.最后,从CF₃对分子的前线轨道贡献可知,四种分子的得电子情况和失电子情况均发生在碳笼本身,并不随着CF₃个数的增加而发生明显的改变. 关键词： 60（CF₃）_n （n=2')" href="#">C₆₀（CF₃）_n （n=2 10） 几何结构和电子性质 密度泛函     

Searching for Flavor-Changing Neutral-Current Signals via e＋e-（γγ） →tcht0 in Topcolor-Assisted Technicolor Model

In the context of the top-color-assisted technicolor （TC2） model, the flavor-changing neutral-current （FCNC） interaction induced by the top-higgs （hOt） are predicted at tree level. We study the relevant processes of e＋e-（γγ）→tcht0 at the International Linear Collider （ILC）. It is found that these rare processes production rates can be enhanced significantly in the TC2 model. Especially for the process γγ→tcht0, the total cross section will reach a few fb in the reasonable parameter space. We also calculate the distributions of transverse momenta, pseudo-rapid and invariant mass of the top-higgs. In view of the main decay modes of top-higgs for mho 〈 2mr, we find that there will be several hundreds FCNC events produced at the ILC with annually integral luminosity of 500 fb-1. Due to the clean background, such FCNC signals can possibly be detected at the ILC.     

Crystal growth of β’—Gd2（Mo4）3 and in situ observation of its domain structure by the microscope and the synchrotron X—ray topography

We report that β’-Gd2(MoO4)3 crystals have been grown by the Czochralski(CZ) method.We studied the growth conditions fo β’-Gd2(MoO4)3 crystal.A compatison between the resistance-heated method and radio frequency induction-heated method is described.Also,the in situ observation of the domain structure by the microscope and by synchrotron radiation X-ray topography under the conditions of DC polarization voltage and tempertature change were carried out.Experiments showed that multidomain structure including ferroelectric and ferroelastic domains occurred in β’-Gd2(MoO4)3 cystal.Usually ferroeletiric domains appeared in the as-grown crystal and ferroelastic domains appeared in the polished thinner piece.Both ferroelectric and ferroelastic domains disappeared when the temperature of the crystal piece was higher than the Curie tempperature Tc and they could be reproduced when the temperature of the crystal piece was lowered below TC.When a DC polarization voltage ranging from 150 to 500V was applied on a c-axis β’-Gd2(MoO4)3 piece having a thickness of 0.5mm ,the multidomain would gradually transform to a single domain.This resual means that it is possible to make a periodically poled β’-Gd2(MoO4)3 crystal.2001 Elsevier Science B.V.All rights reserved.