1998 Vol. 22, No. 1

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Experimental Evidence for the Superdeformation in 81Rb
Pan Qiangyan, Luo Yixiao, De Poli, de Angelis
1998, 22(1): 1-3.
High-spin states in 81Rb were populated in the 55Mn(30Si, 2p2n) reaction at 130 MeV. Prompt γγγ-charged particle coincidences were observed using the GASP spectrometer in conjunction with the ΔE-E silicon ball (ISIS). A superdeformed band consisting of seven γ-ray transitions has been identified. The dynamic moment of inertia for the band is constant with a value of approximately 26.7 h2/MeV throughout the whole observed rotational frequency. This band is interpreted to have a π51v52 intrinsic intruder configuration with a quadruple deformation β2 of 0.51.
Pulsed Emission of Very High Energy Gamma-Rays From Crab Pulsar
Xu Chunxian, He Huilin, He Huihai, Chen Yongzhong, Li Huidong, Jiang Yinlin
1998, 22(1): 4-12.
We present here the results of observation of- very high energy(VHE) gamma-ray emission from Crab Pulsar with Beijing Atmospheric Cerenkov Telescopes, named ACT2 and ACT3, for the duration of the fall 1995-spring 1996 season. The data are based on 168 hours (ACT2) and 125 hours (ACT3) of exposure over the period of observation in tracking model. After conversion the event time to the solar barycenter, the data have been searched for evidence of pulsed emission at 33ms period of Crab Pulsar, We found no steady emission of VHE Gamma-ray with 33ms period at the scale of month or night. But there are two evidences of sporadic emission over an hour duration with the same period as the one at radio frequency.
Origins of the Forward Emission of Complex Fragments for 40Ar+159Tb Reaction at 30MeV/u
He Zhiyong, Li Zuyu, Duan Limin, Zhang Baoguo, Dai Guangxi, Jin Genming, Fu Yanbiao, Wang Hongwei
1998, 22(1): 13-19.
Light charged particles and complex fragments have been measured at forward angles in coincidence with two fission fragments for 40Ar+159Tb reaction at 25MeV/u. These three-body coincident events were sorted as a function of the impact parameter using linear momentum transfer and total transverse momenta methods. Equilibrium statistical emissions of complex fragments from quasi-target residues accompanied by non-equilibrium mid-rapidity components were found to dominate in central collisions, while projectile fragmentations were found to dominate in peripheral collision. Three components of complex-fragments from quasi-target, quasi-projectile and mid-rapidity soures were found in mid-central collision.
Holonomies of Gravitational Connection
Shao Changgui, Chen Zhongqiu, Ma Weichuan, Chen Yihan, Lin Shuyuan
1998, 22(1): 20-27.
The extended loop group and the extended holonomy are consrtucted. The holonomy used in gravity, is obtained using the loop space. For a R+F2 gravity we calculate a classical and a quantum holonomy. the excitation of localized curvature and its expression are obtained.
Algebraic Structure of Two-Parameter Deformed Multi-mode Bose Operators and Their Applications (Ⅱ)
Yu Zhaoxian, Zhang Dexing, Liu Yehou
1998, 22(1): 28-33.
The multi-mode Jordan-Schwinger realizations of the doubleparameter deformed quantum algebra SU(2)q,s and SU(1,1)q,s are given.
Non-Abelian Plasmons and Their Kinectic Equation
Zheng Xiaoping, Li Jiarong
1998, 22(1): 34-40.
After the plasmons modes in QGP are treated as plasmons, the Kinecticequation for the plasmons in linear approximation is established starting from Yang-Millsfields equation. The Kinectic equation can be considered as the balance equation for the number of plasmons, which indicates the balance of the number variation (growth ordamping) in space and time because of their motion with velocities that equal to the wave's group velocity and the emmision or absorption of plasmons by plasma particles.
Reduction of Strangeness Suppression and Strange Antibaryon Production in Sulphur-Nucleus Collisions at 200A GeV
Sa Benhao, Tai An
1998, 22(1): 41-47.
We use the event generator LUCIAE to analyse NA35 data of the p and Λ yields, the transverse mass distributions and the ratio Λ/p in pp and central sulphur-nucleus collisions at 200A GeV. The results seem to indicate that NA35 data might imply the reduction of strangeness suppression in ultrarelativistic nucleus-nucleus collisions comparing to the nucleon-nucleon collision at the same energy. However, the ratio Λ/p approaching to unity in AA collisions comparing to pp collision does not necessarily mean quark flavor symmetry.
Improvement of the Spin Assignment of the Superdeformed Band──Elimination of the ΔI-4 Bifurcation
Wu Chongshi
1998, 22(1): 48-54.
The counterpart which is related to the ΔI=4 bifurcation was separated properly from the observed transition energies. The spins of a superdeformed band may be assigned more accurately by the ab fitting after the ΔI= 4 bifurcation is removed. The spin assignment for the superdeformed bands in 194Hg were re-investigated. A linear increasing is shown in the dynamic moments of inertia and the deflection disappears.
Two-Body Correlation Transport Theory for Heavy Ion Collisions Ⅳ.Conservation Laws
Liu Hang, Liu Jianye, Li Xiguo, Zuo Wei
1998, 22(1): 55-60.
The conservation laws under physical hierarchy - truncation in Two-Body Correlation Dynamics (TBCD) are discussed. The numerical results show that the different physical hierarchy truncations in Two-Body Correlation Transport Theory (TBCTT) are all compatible with conservation laws.
q-Deformation of Three-Parameter Wu-Zeng Formula
Pan Feng, Luo Yanan, Yu Shenqi
1998, 22(1): 61-70.
q-deformed form of the three-parameter Wu-Zeng formula for the description of ground state bands of even-even nuclei is analyzed by taking perturbation theory into consideration. Ground state bands of the most even-even rare-earth and actinide nuclei are fitted using the damped non-linear least square fit. The results show that q-deformed three-parameter Wu-Zeng formula is more accurate than the former three-parameter Wu-Zeng formula derived from the perturbation theory. Furthermore, the new formula describes backbending phenomena much better than the previous one.
Re-Discussion of the Spin Assignments of the Superdeformed Bands in A~190 Region (I) Even-Even Superdeformed Nuclei
Wu Chongshi
1998, 22(1): 71-77.
The superdeformed bands of the even-even nuclei in A~190 region are investigated thoroughly. The observed transition energies are fit to the ab expression to assign the spins with success for most of them provided the influence of the ΔI=4 bifurcation is estimated and removed properly from the r transition energies. For some superdeformed bands the assigned spins obtained in this paper are different from those given by other approaches.
Neutrou Energy Response of a Modified Andersson-Braun Rem Counter from 0.025eV to 45.4MeV
Tang Yueli, Li Jianping, Liu Shudong, Zhang Qingjiang, Cai Xiaoping
1998, 22(1): 78-86.
This paper describes the principle and construction of a modified Andersson-Braun(A-B) neutron rem counter which is used for the stray radiation field of high energy accelerator. The energy responses from thermal neutron to 45.4MeV semi-monoenergetic neutron experiments with four kinds of A-B rem counter were carried out using a few of neutron generating facilitiest The response investigation of A-B rem counters for the stray radiation field outside shielding of 12 GeV proton accelerator was completed. The results show that in the high energy neutron radiation field, the response of modified A-B rem counters is better than that of conventional A-B rem counters.
Casimir Effect of the Maxwell- Chern-Simons Field
Zhang Zhihe, Li Ziping
1998, 22(1): 87-91.
Based on the Faddeev formalism of path - integral quantization for constrained Hamiltonian system, we reexammine the quantization of Maxwell Chern-Simons field, and use the Plana summation formula in the theory of conplex variable function, the Casimir effect belween two parallel lines in the (2+1 ) - dimensional space -time has been calculated, in which we do not use any cutoff of parameter; the finite analytical expression is also obtained.
How to Determine the Spin of the ξ(2230)
Yu Hong, Shen Qixing
1998, 22(1): 92-96.
The possibility for increasing the statistics by summing up the events of decaying into two pseudo scalar mesons from the existing data samples is discussed.