作者机构:
[Chi, LP] Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.;Max Planck Inst Math Sci, D-04103 Leipzig, Germany.
通讯机构:
[Chi, LP] H;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
关键词:
拓扑结构;飞行网络;聚类系数;网络结构;航程;飞机飞行
摘要:
We analyse the directed, weighted and evolutionary US flight network, in which vertices are the airports and the flights connecting two airports represent the edges. It is shown that such a network displays two important features recently found in small-world networks. First, the average shortest-path length is 2.4s, the clustering coefficient of the entire network, 0.618, is greatly larger than that of the random networks with the same N (system size) and 〈k〉 (average degree), 0.065. We study the detailed flight information both in a week and on a whole. In both the cases, using the Pareto distributions, we find the degree distributions follow two-segment power laws. The weight distributions have power-law tails with the exponents of around 2, and the clustering coefficient distributions follow linear distributions.
期刊:
HIGH ENERGY PHYSICS AND NUCLEAR PHYSICS-CHINESE EDITION,2002年26(2):93-99 ISSN:0254-3052
通讯作者:
Bai, JZ
作者机构:
[Bai, JZ] CAS, Inst High Energy Phys, Beijing 100039, Peoples R China.;Liaoning Univ, Dept Phys, Shenyang 110036, Peoples R China.;Hunan Univ, Dept Appl Phys, Changsha 410082, Peoples R China.;Wuhan Univ, Coll Phys & Elect Informat, Wuhan 430072, Peoples R China.;Henan Normal Univ, Coll Phys & Informat Engn, Xinxiang 453002, Peoples R China.
通讯机构:
[Bai, JZ] C;CAS, Inst High Energy Phys, Beijing 100039, Peoples R China.
关键词:
Beijing spectrometer;J/psi particle;Sigma(0) particle;angular distribution;branching ratio
摘要:
With 7.8 million produced J/psi events collected by the BES detector at the BEPC, the decay J/psi-->Sigma(0)Sigma(0) is analysed. The branching ratio is measured to be BR(J/psi-->Sigma(0)Sigma(0)) = (0.97 +/- 0.04 +/- 0.24) x 10(-3). The angular distribution is of the form dN/dcostheta = N-0(1 + alphacos(2)theta) with alpha value of -0.21 +/- 0.27 +/- 0.13.
摘要:
We report a measurement of the absolutely inclusive semileptonic branching fractions of D- and (D-0) over bar mesons, using a data sample of 22.3 pb(-1) collected with BES detector at BEPC e(+) e Collider at roots = 4.03 GeV and based on the method of "combinative D+ and D-0 single and double tags". The measured values of the branching fractions for D- --> e(-) X and (D-0) over bar --> e(-) X are ( 21.8 +/- 8.5 +/- 4.2)% and (8.9 +/- 3.0 +/- 1.6)%, respectively. The measured ratio of the branching fractions is BF(D- --> e(-) X)/BF (D0 --> e (-) X) -2.4 +/- 1.7 +/- 0.8.
作者机构:
[Cai, X; Li, W] Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构:
[Li, W] H;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
关键词:
相互作用强度;广义Bak-Sneppen演变模型;自组织临界态
摘要:
The Bak-Sneppen evolution model is generalized in terms of a new concept and quantity: interaction strength. Based on a quantitative definition, the interaction strength describes the strength of the interaction between the nearest-neighbour individuals in the model. Self-organized criticality is observed for the generalized model with ten different values of interaction strength. The gap equation governing the self-organization is derived. It is also found that the self-organized threshold depends on the value of the interaction strength.
期刊:
HIGH ENERGY PHYSICS AND NUCLEAR PHYSICS-CHINESE EDITION,2001年25(6):465-475 ISSN:0254-3052
通讯作者:
Rong, G
作者机构:
[Rong, G] Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China.;Univ Sci & Technol China, Dept Modern Phys, Anhua 230026, Peoples R China.;Shandong Univ, Dept Phys, Jinan 250100, Peoples R China.;Hangzhou Univ, Dept Phys, Hangzhou 310028, Peoples R China.;Shanghai Jiao Tong Univ, Dept Appl Phys, Shanghai 200030, Peoples R China.
通讯机构:
[Rong, G] C;Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China.
关键词:
Beijing Electron Positron Collider (BEPC);Beijing Spectrometer (BES);D-s(+) Meson;D-s(+) single tag;branching fraction;production cross section;radiative correction
摘要:
Measurement of the production cross section of the D-s(+) D-s(-) in e(+) e(-) annihilation at the Center-of-Mass Energy of roots = 4.03 GeV is reported in the paper. The cross section for the D: DI production has been measured using a data sample of 22.3 pb(-1) collected with BES detector at BEPC e(+) e(-) collider. The D-s(+) measons are reconstructed in the phi pi (+), (K*(0)) over barK(+) and (K-0) over barK(+) decay modes. A total number of 94 +/- 13 singly tagged D-s(+) events is obtained from the three modes. This yelds the cross section value sigmaD(s)(prod+)D(s)(-) = (451 +/- 63 +/- 118)pb for D-s(+) D-s(-) production. Based on the numbers of singly tagged D-s(+) events for each of the three decay modes,the decay branching fractions for D-s(+) --> (K*(0)) over barK(+) and (K-0) over barK(+) have been determined to be (3.02 +/- 0.94 +/- 0.91)% and (3.28 +/- 1.22 +/- 0.94)%, respectively.
作者机构:
[Li, W] Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;Univ Paris 11, INP, F-91406 Orsay, France.;CNRS, IN2P3, F-91406 Orsay, France.;CERN, CH-1211 Geneva 23, Switzerland.
通讯机构:
[Li, W] H;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
摘要:
A quantity f¯ denoting the average fitness of an ecosystem is introduced in the Bak-Sneppen model. Through this quantity, a different hierarchy of avalanches, f0 avalanche, is observed in the evolution of Bak-Sneppen model. An exact gap equation, governing the self-organization of the model, is presented in terms of f¯. It is found that self-organized threshold fc can be exactly obtained. Two basic exponents of the new avalanche τ, avalanche distribution, and D, avalanche dimension are given through simulations of one- and two-dimensional Bak-Sneppen models. It is suggested that f¯ may be a good quantity in determining the emergence of criticality.
作者机构:
[Cai, X; Li, W] Hua Zhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构:
[Li, W] H;Hua Zhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
摘要:
Starting from the master equation for the hierarchical structure of avalanches of a different kind within the frame of the Bak-Sneppen evolution model, we derive the exact formula of the scaling function describing the probability distribution of avalanches. The scaling function displays features required by the scaling ansatz and verified by simulations. Using the scaling function we investigate the avalanche moment, denoted by 〈Sk〉Δf¯. It is found that for any non-negative integer k, 〈Sk〉Δf¯ diverges as Δf−k, which gives an infinite group of exact critical exponents. Simulation outcomes of avalanche moments with k=1,2,3, are found to be consistent with the corresponding analytical results.
通讯机构:
[Li, W] H;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
摘要:
An infinite hierarchy of exact equations is derived for the newly observed f0 avalanche in the Bak-Sneppen model. By solving the first-order exact equation, we find that the critical exponent γ, governing the divergence of the average avalanche size, is exactly 1 (for all dimensions), which has been confirmed by extensive simulations. Solution of the gap equation yields another universal result ρ=1 (ρ is the exponent of relaxation to attractor). Scaling relations are established among the critical exponents (γ, τ, D, σ, and ν) for the f0 avalanche.
期刊:
Il Nuovo Cimento A,1999年112(8):801-808 ISSN:1124-1861
通讯作者:
Li, W
作者机构:
[Cai, X; Li, W] Hua Zhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
通讯机构:
[Li, W] H;Hua Zhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
摘要:
Quark rotation asymmetry is proposed in calculating baryon magnetic moments. After taking into account interactions enforced on constituent quarks, assumed to be linear and Coulomb potentials, respectively, and the quark rotation asymmetry, we fit the theoretical values, based on two more hypotheses and several other reasonable assumptions, of baryon magnetic moments with those from experiments. The good fitting results show the necessity of the consideration of quark rotation asymmetry within baryon.
作者机构:
[Adamovich, MI] Inst High Energy Phys, Alma Ata, Kazakhstan.;Acad Sinica, Inst High Energy Phys, Beijing, Peoples R China.;Inst Gravitat & Space Res, Bucharest, Romania.;Panjab Univ, Dept Phys, Chandigarh 160014, India.;Hunan Educ Inst, Dept Phys, Changsha, Hunan, Peoples R China.
通讯机构:
[Adamovich, MI] I;Inst High Energy Phys, Alma Ata, Kazakhstan.
摘要:
We analyse the multifractal structure of moments G(q) in terms of a new variable X on data of (197)AU, S-32, and O-16 induced interactions with emulsion nuclei and Monte Carlo generated samples. The dynamical properties of the produced particles are mapped onto multifractal spectra. We compare In(G) in experimental data of Au-197, S-32, and O-16 with pure statistical fluctuations. It is shown that the stochasticity plays an important role for the G-moments.