1995 Vol. 19, No. 8

Display Method:          |     

Measurement of J/ψ Resonance Parameters
BES Collaboration
1995, 19(8): 673-685.
The cross sections of e+e→hadrons,e+e+μhave been measured in the vicinity of J/ψresonance at BES/BEPC.The fit of the observed cross sections gives the new results of J/ψ resonance parameters:the partial widths to hadrons,electrons and muous are Γh=74.1±8.1keV,Γe= 5.14±0.39keV and Γμ=5.13±0.52keV respectively;the total width Γ=84.4±8.9keV;the branching fractions Γh/Γ=(87.8±0.5)%,Γe/Γ=(6.09± 0.33)%,and Γμ/Γ=(6.08±0.33) %.
Cross Section Measurements of Neutron-Rich Hg Isotopes in Reaction of 28MeV/u 18O with Thick Natural Lead Target
Wang Jicheng, Zhang Li, Guo Guanghui, Zhao Jinhua, Zheng Jiwen
1995, 19(8): 686-691.
By using 28MeV/u 18O beam,an on-line melting lead target equipment and 4π-ΔEβ-γcoincident technique,the relative cross section ratios and absolute cross sections of neutron-rich nuclides 205—208Hg have been measured. The production cross section of 209Hg is extrapolated.The cross section of 207Hg produced by-2p +1n from target decreases suddenly,which may be explained by change of reaction Q value.
Identifying Tau Hadronic Decay with Neural Network
Chen Guoming, Chen Gang
1995, 19(8): 692-702.
The identification of tau one prong hadronic decay using neural network is presented.Based on the identification,we measured the branching ratios: Br(π/Kv)=(12.18±0.26±0.42)%,Br(π/Kπ0v)=(25.20±0.35±0.50)%,Br(π/K2π0v)=(8.88±0.37±0.38)%,Br(π/K3π0v)=(1.70±0.24±0.39)%.
Nuclear Fragmentation and Particle Production in Interactions Induced by 10.7A GeV 197Au at BNL/AGS
1995, 19(8): 703-712.
Nuclear interactions induced by 10.7A GeV 197Au-ions at BNL/AGS are studied and the recent results on projectile nuclear fragmentation and particle production from the EMU-01 experiment are presented.
Two-Loop Effective Potential of Non-topological Soliton Bag Model at Finite Temperature
Deng Shenghua, Wang Enke, Li Jiarong
1995, 19(8): 713-726.
The two-loop effective potential of the non-topological soliton bag model at finite temperature and finite density is calculated.The influence of thermal effects on the vacuum structure is investigated as well.
Photon-Photon Scattering via Charged Scalar Meson Loops
Yang Maozhi, Zhou Xianjian, Li Xiulin
1995, 19(8): 727-733.
The fourth rank polarization tensor and the helicity amplitudes of γ-γ scattering via charged scalar meson loops in some non-standard models are calculated.They are expressed precisely and analytically in terms of three transcendental functions of B(u),T(u) and I(u,v).
Dimension Formula and an Irreducible Basis of Brauer Algebras
Pan Feng
1995, 19(8): 734-738.
The irreducible representations of Brauer algebras are constructed using an induced representation method.A dimension formula for calculating the irreducible representations of Brauer algebras is derived.
Evolution from Cascade Fission to Prompt Multifragmentation with Increasing Excitation Energy
Wu Heyu, Dai Guangxi, He Zhiyong, Qi Yujin, Li Zuyu, Jin Genming, Luo Qingzheng, Duan Limin, Wen Wanxin, Zhang Baoguo
1995, 19(8): 739-747.
The correlation functions of relative angle distributions of mass-symmetric ternary fissions in the reactions Ar+Au、Bi、Tb at 25MeV/u are presented.The evolution of decay mode of hot nucleus is studied by comparing the present data with Ar+ An(60MeV/u)experimental results.It is shown that the time scale for fragment emission is reduced from the characteristic timeτ=1000fm/c at 25MeV/ufor standard sequential decay to prompt emission one at 60 MeV/u withτ=50 fm/c.
Heavy Quark Effective Theory and Study of Heavy Hadron Spectra
Dong Yubing
1995, 19(8): 748-756.
By employing the heavy quark effective theory,the spectra of heavy hadrons.such as heavy mesons (q),heavy baryons(QQq and Qqq)and heavy multiquark systems(qq)are studied systemically.The results are compared with the predictions for qq in potential model.
Probability Distribution and Entropy of Nonequilibrium State for 208Pb Nuclei Under Different Excited Energies
Pan Zhongcheng, Jiang Shaozhou, Gao Liangjun
1995, 19(8): 757-763.
The probability distribution and the entropy of 208Pb nuclei under different excited energies are calculated.Comparison is made between the probability distributions and the entropies with time for different excited energies.The result shows that our previous calculation is reasonable.
Calculation of Ground State Deformation of Even-Even Rare-Earth Nuclei in sdg Interacting Bosou Model
Wang Baolin
1995, 19(8): 764-768.
The analytical calculation of the nuclear ground state deformation of the eveneven isotopes in the rare-earthregion is given by utilizing the intrinsic states of the sdg interacting boson model.It is compared systematically with the reported theoretical and experimental results.It is shown that the sdg interacting boson model is a reasonable scheme for the description of even-even nuclear deformation.