1991 Vol. 15, No. 12

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Measurement of Semi-Inclusive Charged Particle Pseudorapidity Destributions in pp Collisions at 400GeV/c
WANG Shao-Shun, ZHANG Jie, YE Yun-Xiu, XIAO Chen-Guo, CHENG Zheng-Dong, ZHANG Xue-Qian, LUO Qi
1991, 15(12): 1057-1062.
The pseudorapidity distributions for charged particle multiplicity 8—12 produced in pp collisions at 400GeV/c have been measured by using the LEBC films which were offered by CERN AN27 Collaboration.
The CMS forward hemisphere multiplicity distributions at fixed total multiplicities have been analysed by using cluster model.The results show that the average cluster size is relating to whether the leading-particle effect is taken into account.
Measurement of Charge Changing Cross Sections of 200A GeV S and Fragments with Cu Target
REN Guo-Xiao
1991, 15(12): 1063-1068.
The charge changing cross sections of 200A GeV S and its fragments P,Si,Al,Mg,Na and Ne in collisions with Cu target are measured.It is shown that the cross sections of secondary fragments are larger than that of primary beams with the same charges.The electromagnetic spallation cross sections deduced show a dependence on charges of projectiles which is consistent with theoretical prediction.
Generation of Random Samples of Momentum Fractions of Quarks in the Stochastic Combination Model
LAI Xiao-Ping, FANG Hai-Ping, XIE Qu-Bing
1991, 15(12): 1069-1075.
This paper simply describes the picture of e+e annihilation into hadrons and introduce the distribution of momentum fractions of quarks in the stochastic combination model.The method of sampling from this distribution is mathematically derived.
Dipole Sum Rules in Quantum Mechanics and Electric Depole Transitions of ψ(3770)
DING Yi-Bing, ZHOU Lei, QIN Dan-Hua, ZHAO Guang-Da
1991, 15(12): 1076-1085.
Dipole sum rules in quantum mechanics are generally discussed.The upper and the lower bounds on the electric dipole transition widths of ψ(3770) are estimated.It evidently indicates that the experimental values obtained by Mark Ⅲ collaboration are much larger than the theoretical expectations.
An Unified Formalism to Study Nonstatistical Effects in Radiative Vapture Reactions
YUAN Zhu-Shu, HUO Yu-Kun, LIU Jian-Feng, LU Zu-Hui
1991, 15(12): 1086-1093.
Based upon an consistent description of the wave function of the captured state and the final state,an unified formalism was established to investigate the nonstatistical effects in radiative nucleon capture reactions at energies ranging from 0.1 to 20MeV.This model includes the direct-semidiect capture and the radiative capture in the compound elastic and inelastic channels.By applying this model theory and including also the statistical contributions of the compound nucleus process,the radiative neutron capture cross sections in 27Al,55Mn,89Y and 208Pb are calculated and the results are compared with the measured data.
Phenomenological Analysis and Determination of Spins for Superdeformed Bands in the Mass-190 Region
CHEN Xing-Qu, XING Zheng
1991, 15(12): 1094-1100.
Fifteen superdeformed bands in seven nuclei of the mass-190 region are analyzed by means of the phenomenological model.An overall and excellent agreement between the calculated and observed spectra Er,kinematic moment of inertia J(1) and dynamic moment of inertia J(2) is obtained for all superdeformed bands in the mass-190 region.
M1 Transitions in the Vibrational Limit Case of IBM-Ⅱ
DI Yao-Min
1991, 15(12): 1101-1108.
Two kinds of mechanism of M1 transitions are discussed in the vibrational limit case of IBM-Ⅱ.One is the transition caused by the breakage of F-spin,other caused by the two-body part of the transition operator.It is helpful to the investigation on the realistic M1 transitions of nuclei.
A Simple Formula for Backbending
MENG Jie, YIN Chuan-Zong, LIN Xin-Wei
1991, 15(12): 1109-1114.
Using Wu-Zeng formula to characterize g-band,Bohr-Mottelson formula to describe sband,and introducing a tentative interband interaction,a better description for the yrast,and yrare-band of the most even-even well-deformed nuclei is obtained.The backbending of the moment of inertia is also well reproduced in this formalism.By analysing the parameters used here,other information such as the moment of inertia for the ground state can be concluded.
Pion-Nucleus Double Charge Exchange
JIANG Huan-Qing, Zou Bing-Song
1991, 15(12): 1115-1130.
Present status in theoretical and experimental studies for pion double charge exchange is reviewed in this.Various possible mechanisms for pion double charge exchange are discussed and some open problems are addressed.
Intermittent Behavior Shown in Disassembly of Hot Nuclei
LIU Hong-Min, SA Ben-Hao, ZHENG Yu-Ming, LU Zhong-Dao, WANG Zhong-Qi
1991, 15(12): 1131-1134.
It is presented that by using a simple Monte Carlo simulation and even a partition method the intermittent behavior shown in the fragment charge distribution from the isassembly of Au* can be reproduced.That seems to indicate that the scaling law between factorial moment and resolution is not necessarily associated with intermittent behavior.
Neutrino Mass and the Superstructure of the Universe
HUANG Wu-Liang
1991, 15(12): 1135-1136.
From the superstructure of the universe with a scale larger than 102 Mpc we deduce that the universe may be dominated by hot dark matter (neutrinos),which mass mv~10-1eV(0.16eV).