1999 Vol. 23, No. 02

Display Method:          |     

J/ψ Physics at BES
BES Collaboration
1999, 23(02): 97-102.
Based on 9.0×106 J/ψ data collected at BES, a systematic physics analysis has been Performed. We confirmed the existence of ξ(2230) in J/ψ→γKK and observed for the first time the non-strange decay modes ξ(2230)→π+π0π0,and pp. The resonance and polarization parameters of f0(980) and f2(1270) were measured. The moment stUdy on J/ψ→γK+K revealed that the controversial fJ,(1710) is composed of two states, a 0++ and a 2++. With the help of PWA method, the spin-Parities for η(1440) and f0(1500) were obtained, and their main decay modes were found.
Status and Prospect of Yangbajing Cosmic Ray Experiment
Tan Youheng
1999, 23(02): 103-109.
The geography advantages of Yangbajing, the results and significance of Tibet AS Array-I, the challenges and choices faced by us are summarized. A project aiming at the ~100GeV γ-ray astronomy, the cosmic anti-proton measurement the monitoring of solar achvity and the breakthrough of the "Knee physics" barrier by means of RPC carpet large air cherenkov telescopes and complex AS Array, was proposed.
Recent Developments of Physics at TeV Energy Scale
Kuang Yuping
1999, 23(02): 110-116.
The situation of future TeV energy colliders and recent developments of theorehcal studies of physics at TeV energy scale are brief'ly reviewed.
Top Physics Status and Outlook
Li Chongsheng
1999, 23(02): 117-134.
We briefly review the status of the top quark physics and summarize the potenhal of various measurements in experiments at future colliders associated with the productions and/or decays of the top quarks.
Understanding the Meson States and Non-qq States
Wu Jimin
1999, 23(02): 135-141.
By studying the behavious of Regge trajectories of the boson resonances and comparing with the predictions from quark model, we understand more the existing scalar, tensor, pseudoscalar particles and non-quark-antiquark states. One can find some resonances are non-qq states.
New Progresses in Deep Inelastic Scattering in Small x Region
Peng Hongan, Xu Jiasheng
1999, 23(02): 142-150.
Recent data on lepton-nucleon (nucleus) deep inelashc scattering at lowBjorken x region and diffractive machanism are reviewed in the light of newtheoritical and experimental progresses with panicular attenhon to target rest systemscheme.
Supersymmetric Grand Unification Theories and Low Energy Physics Phenomena
Wu Yueliang
1999, 23(02): 151-154.
in this talk, I briefly show why it is necessary to go beyond the standard model (SW). As one of the most interesting extensions of the SM, I mainly discuss supersymmetric grand unification thoeries and their low energy physics phenomena.
Effective Lagrangian Theory
Wang Qing
1999, 23(02): 155-164.
From view point of modem field theory, all theories for realistic interaction are effective, which come from some more elementary theory. One main feature of effective theory is that it include infinite number of interaction terms. Effective theory is different with standard renormalizable field theory. Here, we focus on a class of special effective theory-effective chiral Lagrangian in strong interaction, discuss its features and present status of its development. We don't involve heavy quark effechvefield theory and N'RQCD and the combinahon of these theories and effective chiral Lagrangian.
New Progress in the Study of High Energy Non-Linear Phenomena
Liu Lianshou
1999, 23(02): 165-175.
Classical Chromodynamics has chaos solution. But quantum chaos is a very difficult theoretical problem. Therefore, at present the non-linear study in high energy physics can only be carried on using phenomenological methods. By the end of eighties, large local fluctuations were observed in experiments, which stimulated extensive study on high energy non-linear phenomena—intermittency and fractal. It was observed experimentally that l-dimensional factorial moments tend to saturate. This was explained as the result of projechon of higher-dimensional intermittency into lower dimension. However, even in 3-dimension the factorial moments do not obey a strict scaling law. ms difficulty has brought the study to a standstill. Later, it was recognized that the reason lies in the fact that the phase space of high energy multiparticle final states is highly anisotuopy and therefore the corresponding fractal is self-affine. The anomalous scaling can be observed when and only when the phase space is divided in a correct anisotropical way. Thi predichon has been verified in the experimental data from NA22 and NA27. The anomalous scaling in these experiments has been observed successfully, making a breakthrough in high energy non-linear study. This progress is reviewed in mis paper together with some comments and discussions.
Relativistic Heavy Ion Collisions and Quark Matter
Zhuang Pengfei
1999, 23(02): 176-187.
The recent progress in the field of relahvistic heavy ion collisions and quark matter is reviewed. Especially, the QCD thermodynamics, quantum transport theory, and some hot topics related to the QCD phase transitions are analyzed in detail. The outlook for thes field is also briefly discussed.
Recent Advances in Lattice QCD
Luo Xiangqian
1999, 23(02): 188-194.
Lattice QCD is the most reliable non-perturbahve method in quantum field theory, and one of the fronhers of particle physics. It has widely been applied to its overlapping fields, and has greatly influenced the development of physics and other sciences. This paper reviews some recent progress which is of great theoretical and experimental interest.
Spin Effects and High Energy Reaction Mechanisms
Liang Zuotang
1999, 23(02): 195-198.
ms is the written version of my talk given at the sib Chinese National Conference on High Energy Physics held in Chengde, April 21st to 25th, 1998. A number of striking spin effects have been observed in high energy hadron-hadron collision experiments. Searching the origins of these effects has been and is a hot topic in High Energy Physics. In the past few years, with the common efforts of the experimentalists and theorehans, a large step forward has been made although many questions still remain to be answered. T'hese results show that the study of the origins of these effects can indeed provide useful information for hadron structure and high energy reaction mechanisms. It shows also that these effects themselves can be used as a tool to probe these mechanisms. For example, it has been pointed out that, they may be used to study the properties of reaction of small-xB virtual photon with hadrons. In this talk, I will briefly summarize the experimental results on these effects and the main conclusions of the theoretical studies, and then make a brief introduction to the main ideas and the results.
Analysis of B→η′K(K*),ηK(K*) Decay Processes
Du Dongsheng
1999, 23(02): 199-203.
The new data of B→η′K(K*), ηK(K*) are presented and analysed. All Possible theoretical explanations are briefly introduced. The experimental test of some decay mechanisms is discussed.
Non-Negligible Electroweak Penguin Effects
Guo Libo1, Li Xingyi2
1999, 23(02): 204-211.
Starting from the leading logarithmic low energy effective Hamiltonian and the Baner-Stech-Wirbel(BSW) model, we calculate the electroweak penguin effects in the two-body hadronic pure penguin processes of B-meson. In the case of B-PP and PV decays, we find that the processes involving external Penguin diagrams receive large contributim from electroweak penguin effects which can even play dominant role.
Casimir Energy for Piecewise Uniform Strings
Lu Jizong1, Huang Baofa2
1999, 23(02): 212-215.
The Casimir energy can be considered as the polarization of the vacuum energy of quantized fields due to the distortion caused by the presence of boundaries, the curvature of the space-time mani-fold or some background fields. The study about the Casimir energy can deepen our understanding of the substance of the quantum fields, so the interest in studying Casimir effect has been enhanced recently. Brevik et al. studied the Casimir energy of piecewise uniform strings first. However, they only discussed the one of closed bosonic strings. In this paper, we extend their resaerch to both open and closed bosonic strings, as well as fermionic strings. The energy of superstrings is investigated briefly too.