1989 Vol. 13, No. 7

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Review
THE GAS GAIN OF PROPORTIONAL COUNTING TUBES
LI Huan-Tie
1989, 13(7): 577-585.
Abstract:
In this paper the gas gain of proportional tubes are discussed.On the basis of analysing several calculation formulas,another α/p-E/p relation and correspondent formula of gas gain is proposed.The theory is compared with experimental data of BF3 and CH4 proportional tubes.
MUON COUNTER IN BES
ZHU Yong-Sheng, ZHANG Liang-Sheng, GAO Wen-Xiu, ZHANG Yi-Ping, ZHAO Ping-De, ZHANG Jia-Wen, LI Fang, CHEN Le-Jun, XU Zhi-Qing
1989, 13(7): 586-593.
Abstract:
The arrangement and design performance of muon identifier in Beijing Spectrometer (BES) are described.The gas gain.Plateau feature,drift time,detection efficiency,charge division for hit location and other characteristics of muon counter modules have been measured.
THE VIRASORO ALGEBRA ON TORUS WITH GENERAL METRIC
XU Kai-Wen, SHEN Jian-Min
1989, 13(7): 594-599.
Abstract:
We discuss the Virasoro algebra on torus with a general metric.First we give the complex structure and the stress-energy tensor on torus with a general metric.Then we solve the equations of motion for bosonic string and their ghost fields under the general metric,and obtain the general solutions of the equations.Finally,we give the Virasoro algebra on torus with a general complex structure,and show that different complex structures have the same Cirasoro algebras.
A FOUR-DIMENSIONAL HETEROTIC STRING
GONG Shang-Qing, QU Li-Hu, YU Shou-Mian
1989, 13(7): 600-606.
Abstract:
We constructed a new D=4 heterotic string,which combines the right-movers of the D=4 fermionic string with the left-movers of the D=10 N-S bosonic strings.Its gauge group is [SU(2)]6.The massless ground state of the string consists of D=4 supergravity and super- Yang-Mills bosons.The new string theory is tachyon-free,Lorentz invariant and supersymmetric.
QCD PREDICTIONS FOR THE SEA QUARK DISTRIBUTION FUNCTION IN HADRONS
SHEN Qi-Xing, WU Ji-Min, SONG Xiao-Tong, DU Jian-Guo, ZHANG Hong-Xian
1989, 13(7): 607-613.
Abstract:
We get the analytical series expressions for the sea quark distribution function in hadrons from Altarelli-Parisi equation.The calculated values,which relate to the sea quark distribution function,are consistent with experimental data.
ASYMMETRY FOR π+ SINGLE CHARGE EXCHANGE FROM ALIGNED NUCLEUS 165Ho
PAN Ling-Jun, JIANG Huan-Qing
1989, 13(7): 614-619.
Abstract:
In the framework of the eikonal theory and using the π nucleus optical potential including the second-order correction,we calculate the asymmetries for π+ single charge exchange from aligned 165Ho at Tπ=165MeV incident pion energy.The sensitivity of the asymmetry variable to the deformation of the neutron distribution in well-deformed nuclei is also studied.The angular distributions of the asymmetry variable As(θ) are predicted.
Q2-AND x- RESCALING AND NUCLEAR MOMENTUM CONSERVATION IN THE EMC EFFECT
LI Guang-Lie, LIU Ke-Fei
1989, 13(7): 620-626.
Abstract:
With the Fermi motion corretion including the nuclear binding effect,we show that the major features of the EMC effect can be explained by using the Q2- or x-rescaling mechanism.The x- rescaling mechanism can fit the experimental data better than the Q2- rescaling mechanism in the region of 0.22- or x- rescaling parameters for the valence and sea quark momentum distributions in the nucleon structure function.It shows that by using the extended x- rescaling mechanism one can obtain a better agreement with the experimental data in the small x region.
STUDY ON CROSS SECTION OF THE SHORT LIFE EVAPORATION RESIDUES IN REACTION 12C+112Sn
WANG Su-Fang, CAI Wei, ZHENG Ji-Wen, LIANG Guo-Zhao
1989, 13(7): 627-631.
Abstract:
Measurement of the evaporation residues from the bombardment of 52—71MeV 12C ion on 112Sn have been performed by means of γ-ray detection.The residues have been transported from inside of the target chamber to the detection port by using a special device,and detected by a Ge(Li) detector.Only the relative cross secticns have been obtained.
THE SUPERDEFORMED BANDS IN Nd AND Ce NUCLEI
LUO Yi-Xiao, ZHONG Ji-Quan
1989, 13(7): 632-641.
Abstract:
Superdeformed bands in 133,134,137Nd and 131Ce are found in a systematic study of the high spin,superdeformed light rare earth nuclei.Also the previously reported superdeformed pands in 135,136Nd and 132Ce are confirmed and further investigated.The experimental search procedure,identification and measurement of the superdeformed bands are described in detail.The systematics in feeding.decay,moment of inertia,relative intensity and structure of the bands are discussed.
SELFCONSISTENT SEMICLASSICAL CALCULATION WITH EXTENDED SKYRME FORCES AND THE PROPERTIES OF ISOSCALAR GIANT RESONANCES
LI Guo-Qiang, XU Gong-Ou
1989, 13(7): 642-651.
Abstract:
The HF energy density functional H [ρnp] is obtained by utilizing the kinetic energy density sunctional τqnp] and spin-orbit density functional Jqnp] in semiclassical approximation.The nuclear ground state densities are determined by varying the functional with respect to ρn and ρp under certain conditions.A series of nuclear static and isoscalar giant resonances properties are evaluated with above determined densities.All the results are in good agreement with experimental and HF(RPA) ones.
NON-RELATIVISTIC BUU EQUATION
GE Ling-Xiao, ZHUO Yi-Zhong
1989, 13(7): 652-663.
Abstract:
The Boltzmann-Uehlig-Uhlenbeck (BUU) equation,which is the time evolution of the wigner function of the single particle Green's function,is derived by using the closed-time Green's function approach.The quantum mechanical approximation in deriving the BUU equation is discussed.
INTERACTIONS OF NUCLEI AND LASER(1) ——LASER INDUCED ISOMERIC TRANSITIONS AND GAMMA LASER
HUO Yu-Kun, PAN Zheng-Ying
1989, 13(7): 664-669.
Abstract:
Laser induced nuclear transitions between isomeric states were calculated by a parametrization approach.The effect of laser linewidth were taken into account.Based on the calculated transition probabilities,laser stimulated conversion from long to short lifetime states was studied.The kossibility of changing the lifetime of the long-lived isomers and developing gamma-ray laser is discussed.Numerical evaluations show that the laser intensity required to develop gamma-ray laser in this approach is higher than that available at nowdays technology.
THE STRING TENSION OF 2+1 DIMENSIONAL SU(2) GAUGE THEORIES
LI Zhi-Bing, ZHENG Wei-Hong, GUO Shuo-Hong
1989, 13(7): 670-672.
Abstract:
We present a variational calculation of string tension in 2+1 dimensional SU(2) lattice gauge theory using two kinds of Hamiltonian in which the exact ground states are known.