1987 Vol. 11, No. 5

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Review
A 45° PROTOTYPE OF THE CENTRAL DRIFT CHAMBER FOR BES AND RESULTS OF COSMIC RAY TEST
CHEN Chao-Qing, DENG Yi-Wei, LI Ru-Bai, LIU Rong-Guang, SHI Huan-Zhang, WU Jian-Wu
1987, 11(5): 577-583.
Abstract:
It is described that the function,structure, amplitude characteristics and results of cosmic ray test of a prototype of the central drift chamber for Beijing Spectrometer (BES). It was found that if appropriate high voltage is applied on the field wires homogeneous signal amplitude from different Layer of the chamber can be obtained. The drift velocity deduced by track reconstruction is 5.3cm/μs. The spatial resolution is about 134μm.
THE PROPER CHOICE OF CLEARING FIELD OF THE SPARK CHAMBER
XU Zhen-Ye, WANG Ming-Xing, WANG Yi
1987, 11(5): 584-588.
Abstract:
Based on the basic principle of the function of the parrallel plate spark chamber, two formulae relating the clearing field to the detection efficiency and sentive time are derived. The validity of these formulae are tested by experiment and shown that they are useful in the choice of the clearing field properly for experiments.
THE INVESTIGATION OF THE HIGH DENSITY MULTIWIRE PROPORTIONAL CHAMBER AS A DETECTOR FOR NEUTRAL PARTICLES
WANG De-Wu, LOU Jia-Shu, LI Zhi-Gang, YAO Zong-Yuan
1987, 11(5): 589-595.
Abstract:
This paper describes a position sensitive multiwire proportional chamber with effective area of 200×200mm2. The chamber combining with multi-layer lead γ-ray converter form a high density multiwire proportional chamber γ-ray detector. The lead converter is made in auniformly arranged matrix of 0.9mm diameter holes on a 1.1mm pitch. For 511keV photons the detection efficiency is 5.6%, and the spatial resolution is 1mm. The detector has been used in the investigation of positron camera, it also offers possibility for X-ray detection.
ANALYSIS OF HADRONIC EVENTS
DONG Bao-Zhong
1987, 11(5): 596-602.
Abstract:
In this paper I summarize some results obtained from analyses of hadronic final state events. The analyzed data sample comes from Mark-J collaboration and covers an energy range from √S=12GeV to √S =46.78GeV. The integrated luminosity is 128.06Pb-1. We can search for production of open top quarks and toponium by measuring the total hadronic crossection R =3.85±0.02±0.12 was measured in the above mentioned energy range. It is consistent with R≈3.9 as expected from QCD for five different quark flavors. We search for the narrow bound states of the toponium from 39.79GeV to 46.78GeV. The most prominent resonance signal is at a c.m. energy √S=45.12±0.04GeV and results in an upper limit of Bh.Γee≤3.00keV(95% C.L.).
RING-LIKE EVENT OBSERVED IN SUPERHIGH ENERGY INTERACTION AND PHASE TRANSITION
JING Gui-Ru, DING Lin-Kai, ZHU Qing-Qi, JING Cai-Liu
1987, 11(5): 603-608.
Abstract:
The kinematical analysis of the ring-like event observed in mountain emulsion chamber shows that this kind of events might relate to the multi-particle production within a narrow rapidity interval of the fragmentation region in the superhigh energy interactions, therefore possibly relate to the phase transition in the nucleus-nucleus interaction. The air cascade showers induced by superhigh energy nucleus-nucleus interactions are simulated by a transition model. Under the condition of the emulsion chamber experiment, the ring-like event is obtained.
A NEW KIND OF POCKET GAMMA-NEUTRON DOSERATE CHIRPER
LEI Chuan-Heng
1987, 11(5): 609-613.
Abstract:
In order to avoid unnecessary or unallowable exposure in the gamma-neutron mixed field, the radioactive-contact person should know the radiation environment at any time by himself when he is working. A new kind of pocket radiation doserate monitor (chirper) based on silicon PIN photodiode as detector is designed. It can be used to monitor the gamma doserate in the order of 1 mrem/h and the neutron doserate in the order of 10 mrem/h simultaneously. In this paper, the detector selection, the circuit design, the construction and the performance of the chirper prototype are described.
THE LOCALLY PRODUCT STRUCTURE OF INTERNAL SPACE AND SOME OF THE PROPERTIES IN HETEROTIC STRING ACTION
GAO Hong-Bo, SUN Yi
1987, 11(5): 614-619.
Abstract:
This paper is devoted to a study of the heterotic string action described by a (p,q)-type supersymmetric σ-model involving a two-rank antisymmetric tensor field (Wess-Zumino-Witten term). We discussed a certain quantization procedure of W-Z-W term and its impact on heterotic string by using the locally product structure of internal compact space.
LEVINSON'S THEOREM FOR KLEIN-GORDON EQUATIONS WITH POTENTIAL TAILS
DAI An-Ying
1987, 11(5): 620-628.
Abstract:
In terms of the modified Sturm-Liouville theorem, the properties of the solutions to the Klein-Gordon equations with the potential tails is discussed and the corresponding Levinson's theorem is proved in this paper.
A METHOD OF COMPUTING THE EFFECTIVE COLOR DIELECTRIC CONSTANT AND THE BAG RADIUS OF NUCLEONS IN NUCLEI
HE Zhen-Min
1987, 11(5): 629-633.
Abstract:
Using the parabolic Fermi distribution of the nucleon number density instead of the average density, a new method of computing the effective color dielectric constant and the nucleon bag radius in nuclei is presented, so that the physical picture is made more realistic, and the results thus obtained are better consistent with the data and have two new features.
REALIZATION OF THE EMBEDDING OF LIESUBAL GEBRA IN THE CASE OF INTERACTING BOSON MODEL
TU Chuan-Shi
1987, 11(5): 634-643.
Abstract:
This article treats the interacting Boson model (IBM-1) by the embeding theory of Lie subalgebra. From the considerations of stantard A1 subagbra and the index relation of the embedding theory, we can get all the subagbra chains of IBM-1 model and prove that they exhaust the possible physically meaningful chains.
The Boson creation and annihilation operators are taken as basis for the realization of the embedding. In selecting the basis, angular momentum consideration is very crucial for the outcome of the correct physical result which has angular momentum as a good quantum number. Our results coincides with the original resul of Arima and Iachello.
GORDON DECOMPOSITIONS FOR γ-TYPE MATRICES AND SOME OF THEIR APPLICATIONS
SU Jun-Chen, WU Shi-Shu
1987, 11(5): 644-652.
Abstract:
In this paper, some decomposotion formulas of γ-type matrices are derived based on Gordon identities. As an illustration of the application of these formulas, the one gluon exchange potential between quark and antiquark is rederived which appears to be different from that obtained by Faessler, et al. As another illustration, the correct reduction of the γ-matrices appearing in the kernel function of Bethe-Salpeter equation for quark-antiquark system is achieved and yields an expression different from that derived by Mitre whose calculation was grounded on a wrong decomposition formula for one γ-type matrix.
THE STUDY FOR 8Be(g﹒s) DETECTION EFFICIENCY
ZHANG Li, JIN Hao-Qiang, JIN Gen-Ming
1987, 11(5): 653-659.
Abstract:
The energy reponse in the effective solid angles and the spatial distribution of the detection efficiency for the four frequently used 8Be detection systems are obtained by two methods: Monte Carlo simulation and integration of the distribution function. The agreement of the results by the two methods is good. The resultes are tested are tested by some measurements with different geometry and compared with the published data.
RECOIL STUDY OF RESIDUAL NUCLEI I AND Sb IN THE REACTION INDUCED BY 12C ON 115In
SUN Tong-Yu, LI Wen-Xin, DONG Tian-Rong, JIN Gen-Ming, FU Min, SUN Xiu-Hua, SUN Xi-Jun
1987, 11(5): 660-666.
Abstract:
Excitation functions and angular distributions of the residual nuclei I and Sb were measured in the reaction of 12C on 115In at energies up to 72MeV using radiochemical techniques. A kinematic analysis of the angular distributions showed probable mechanisms leading to productions of I and Sb isotopes.
ON THE REACTION MECHANISM OF ALPHA TRANSFER REACTION FOR 16O(16O, 12C)20Ne
GAO Cheng-Qun, HE Guo-Zhu
1987, 11(5): 667-673.
Abstract:
The oscillatory structure appeared in the differential cross section of the reaction for 16O(16O, 12C)20Ne may be explained by particle transfer from covalent channel to ionic channel in the nuclear molecular orbital theory.
MASS DRIFT IN HEAVY ION REACTION
GE Ling-Xiao, SHEN Wen-Qing, LIU Jian-Ye, WU Guo-Hua
1987, 11(5): 674-681.
Abstract:
A simple model by which the mass drift can be expected in heavy ion reaction is suggested. The drift of average value of mass distribution with increasing dissipation energy is very small, because large damping effect hinders the driving potential in the process of energy equilibration while in the process of fast fission the drift of mass distribution increases rapidly and reaches equilibrium which comes from the effect of driving force.
APPROXIMATE ANGULAR MOMENTUM PROJECTION OF THE DEFORMED HARTREE-FOCK STATE FOR K=1
LIAO Ji-Zhi
1987, 11(5): 682-689.
Abstract:
Using our approximate angular momentum projection method with one parameter, the projection spectra of the axially symmetric Hartree-Fock intrinsic states are studied. The approximate and the exact projection matrix elements are obtained and compared each other. The projection integrals for angular momentum J=1 to 11 are given. The energy spectra of the nuclei 44Ti and 50Ti are calculated, and the results coincide with the observed energy levels fairly well.
THE CONTROLLED ANNIHILATION PRINCIPLE OF PARTICLES AND ANTIPARTICLES
WEI Kai-Yu
1987, 11(5): 690-694.
Abstract:
In this paper, a controlled annihilation principle of particles and antiparticles is suggested. The particles and antiparticles are kept in a common space by an electromagnetic field to form an equipartisma or semiequipartisma. The equipartisma and simiequipartisma are new meaterial form, they can annihilate themselves and liberate their energy at usual temperature. One may control the annihilation life-time and energy liberated speed with adjustment of the particle and antiparticle density.
TWO-BODY EFFECT IN HEAVY ION COLLISION
GE Ling-Xiao, LIU Jian-Ye, WANG Shun-Jin
1987, 11(5): 695-698.
Abstract:
A simple relaxation equation have been obtained from the master equation of the occupation number by means of the time average approximation in the dissipation diabatic dynamic theory. Contributions from one-body and two-body collision processes to the rate of occupation number have been compared quantitatively.
THE PROBLEM OF THE COSMOLOGICAL CONSTANT
ZHA Chao-Zheng
1987, 11(5): 699-703.
Abstract:
The cosmological term is necessaritly vanishing in a conformal gravitational theory, and the sum of the induced cosmological constants of all the brocken gauge symmetries cancels the curvature of the background spacetime. Thus the sum of all the cosmological constants is vanishing when the background spacetime is Minkowskian. Furthermore, the spontaneous breaking of a gauge symmetry through the Higgs mechanism is always accompanied by a phase transition of the background spacetime.
INTERNAL MOTIONS OF 3-BODY SYSTEMS UNDER PAIRWISE INTERACTIONS WITH ATTRACTIVE TAIL AND REPULSIVE CORE
BAO Cheng-Guang, QIU Guo-Chun, CAO Heng-Dao, GAN You-Ping, LUO Li-Xiong
1987, 11(5): 704-707.
Abstract:
A detailed analysis of the particle-particle correlation has been made and modes of internal motions have been found.
THE ΛN INTERACTION AND THE HYPERNUCLEUS 40ΛCa
NING Ping-Zhi
1987, 11(5): 708-712.
Abstract:
Calculations have been performed for the energy separation of the two major substitutional states of the hypernucleus 40ΛCa. The (K) cross sections are calculated in the framework of the distorted-wave impulse approximation. Information about the ΛN interaction is then extracted, particularly, on the effects of the strength parameters on cross sections. The result shows that the ΛN interaction adopted previously for the 1p shell hypernuclei might be suitable to use for the (K) reaction in which medium heavy hypernucleus 40ΛCa are produced, but the value for the strength parameter of the central potential has to be changed from 0.99 to 0.78.
AN IMPORTANT MESSAGE IN THE K0-K0 MIXING SYSTEM
WU Dan-Di
1987, 11(5): 713-716.
Abstract:
The rephasing invariant formulation for the K0-K0 system is given and used to discuss the signs of the B parameter in M12 calculation andsin δ in the K-M matrix (both are positive). The meaning of the singularity appeared in the exact formula of the ε parameter, which does not appear in the popular formula in the literature, is also discussed.
LONG RANGE CORRELATION SINGLE PARTICLE SPECTRUM AND PION CONDENSATION IN PROTON-NUCLEUS COLLISION
LI Yang-Guo, LU Sui-Xian
1987, 11(5): 717-720.
Abstract:

The combination of partition temperature with Bose-Einstein statistics is generalized to describe the proton nucleus collision. The rapidity distribution of pp, p-Ar and p-Xe at PL=200GeV/c have been calculated and compared with experiment. The interesting possibility of observing pion condensation in p-A collision is investigated.