1991 Vol. 15, No. 7

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BES Offline Data Processing
XU Rong-Sheng, LANG Peng-Fei, CHEN Ya-Qing, ZHANG Shao-Qiang, PAN Ling-Jun, WANG Tai-Jie, HUANG De-Qiang, ZHANG Da-Hua, ZHENG Min, JIA Qiu-Ping, HE Ju, GAO Yuan-Ning, HUANG Yin-Zhi, MA En-Cheng, ZHAO Zheng-Guo, LIU Feng, CHEN Shao-Min, ZHANG Xue-Yao, LI Qun
1991, 15(7): 577-583.
Data production of BES offline analysis is described,filter criteria of events are presented,and the division of the DST data,the reconstructed events,is introduced.Some physics signals first seen in BES from preliminary analyzing are also shown in this paper to prove the reliability of BES data.
On the ηc Particle and Its Electromagnetic Decays
DING Yi-Bing, QIN Dan-Hua, ZHAO Guang-Da, ZHOU Lei
1991, 15(7): 584-590.
The mass,width and branching ratios of the ηc meson are estimated in the framework of a potential model.It is shown that it is possible for the width of the forbidden M1 transition ηc→J/ψγ to raise one order of magnitude after considering relativistic corrections is comparison with the non-relativistic result.The possibilities to measure the cascade electromagnetic radiation processes ψ′(3686)→γηc→γγ1P1,γγJ/ψ,3γ with BEPC are discussed.
Removability of the Topological Term in the O(3) Nonlinear σ-model
GAO Xiao-Chun, XU Jing-Bo, YAN Ji-Jin, LI Wen-Zhu
1991, 15(7): 591-597.
It is shown that the topological term in the O(3) nonlinear σ-model can be removed by a suitable canonical transformation in the classical theory of the model.In this paper,the quantum unitary transformation corresponding to the classical canonical transformation is found.The meaning of the unitary transformation and the removability of the topological term are then discussed.
A Solvable Model in Two-Dimensional Quantum Gravity
YAN Jun, HU Shi-Ke
1991, 15(7): 598-605.
The solvability of the wave-function in (1+1)-dimensional quantum gravity is studied by introducing a scalar matter field.Similar problems in two-dimensional supergravity model are also considered.
Effect of Secondary Collisions on the K++ Ratio in RHIC
ZHU Yun-Lun, ZHAO Wei-Qin, GAO Chong-Shou
1991, 15(7): 606-614.
In this paper,the effect of different secondary collision on the increase of the K++ ratio in RHIC is analyzed based on a participant-spectator picture,using Monte Carlo simulation.Our results show that the increase of the K++ ratio resulting from the secondary collisions alone is insufficient to explain the experimentally obtained result.
The Saturation Phenomenon of Transverse Energy Distribution in Heavy-Ion Collisions and Multisource Modle
ZHANG Kun-Shi, LIU Lian-Shou
1991, 15(7): 615-622.
Based on a careful analysis of the mechanism of high energy non-equal mass nuclei collisions,the multisource modle is further developed.The transverse energy distribution in central rapidity region at both CERN and BNL energy domains are calculated.The saturation of transverse energy distribution at low energy is explained,and the minimum mass number of the target nucleus for this saturation effect (full stopping) to occur is obtained.
A Study of the Cross Sections and the Spin Observables for p-12C Scattering in the Intermediate Energy Region
HE Gan-Ming, LI Qing-Run
1991, 15(7): 623-629.
The differential cross sections and the spin observables of p-12C elastic scattering in the whole intermediate energy region are calculated in the Glauber theory.The theoretical results show considerable deviations from the experimental data.
The Prediction of Proton Decay for Neutron Deficient Nuclei with A<70
XU Xiao-Ji, QU Xiu-Lan, CHENG Yuan
1991, 15(7): 630-646.
The possibility of proton decay for neutron deficient nuclei far from β stability is predicted in the mass region with A<70.The prediction calculation was based on kelson-Garvey mass relation and the mass formula of isospin analog state.The predicted nuclear chart was given.The comparisons between the predictions and the experimental results have been made.The possibility of two proton and three proton decay was also indicated.
An Investigation of G Pair Included Fermion Dynamical Symmetry Model for Medium and Heavy Mass Nuclei
PAN Feng, CAO Yu-Fang, PAN Zhen-Yong
1991, 15(7): 647-654.
A new description of the hexadecapole degree of freedom in the medium and heavy mass region in the framework of the Fermion Dynamical Symmetry Model (FDSM) is proposed.In this paper,the k-active case is discussed in detail,in which the pairing and multipole operators generate SP10 group.The energy spectra are derived for two limits of the pairing,quadrapole and hexadecapole strength.Finally,the spectra of 204Pb are fitted and compared with the experimental values and the results obtained from sdg IBM.
The Study of the Anomalous Transition Rates of 161Lu
WU Xing-Ju, CHEN Xing-Qu, XING Zheng
1991, 15(7): 655-659.
Anomalous phenomena of the transition probabilities in 161Lu are investigated.The observed drastic increase in the magnitude of the B(M1)/B(E2) after band crossing is a result of nuclear shape change,both in the β deformation and in the γ deformation.
g-Boson Degree of Freedom in Vibrational Regions
DI Yao-Min
1991, 15(7): 660-668.
The g-boson degree of freedom in the vibrational regions is discussed in term of the energies and the electromagnetic transitions.Several closed expressions for the rates of M1,E2 transitions and the E2,M1 mixing ratios are obtained.Some survey is made and it reveals it is meaningful to investigate the g-boson degree of freedom in those regions.
A Mechanism for SQS Avalanche
CHEN Ji-Ge, XU Zi-Zong, CHEN Hong-Fang, MA Wen-Gan
1991, 15(7): 669-672.
Based on a large amount of experimental nformations,it is assumed that SQS avalanche is developed when the electric field around the anode wire is heavily distorted by the space charge accumulated in the primary avalanche.Following this assumption the calculations are performel.The dependence of charge output on the high voltage of the counter is presented.Some key quantities,such SQS-transition voltage Vtr and charge output Qpt and Qst are calculated.Their dependence on gas composition is Presented.