α-Nucleus Scattering at High Energies

In this paper ,the differential cross sections of the elastic and inelastic scattering of alpha-particle of energy 1.37GeV on the 2⁺ and 3^－ excited states of ¹²C and Ca isotopes are calculated by the method of the inelastic two-composite-particle system scattering theory at high energy.The results are in agreement with experimental data.The importance of the virtual excitation in calculating the differential cross section of the elastic is descussed.     

Study of Nuclear Level Structure in Tc Isotopes with Mass A～100

In the present work, the structures of the excited positive/negative-parity yrast states of ¹⁰¹Tc are discussed by using a projected shell model, and a band diagram calculated for the positive-parity yrast band is also shown in order to extract physics out of numerical results. In addition, the analysis of other three bands originated from 3/2^－[301], 5/2^－[303], and 1/2⁺[431] Nilsson states, respectively, is also performed in the framework of this model. Until recently, very little property about the N=52—54 intermediate nuclei in the Z～42—44 region has been known. In order to understand these "transitional nuclei", we select the nucleus ⁹⁵Tc as an example. So in this work, we also present our investigation of the level structure in the ⁹⁵Tc nucleus.     

非束缚核11N共振能级研究

简要回顾了目前有关非束缚态核¹¹N的实验研究现状,并根据GANIL和MSU的逆运动学弹性共振散射实验的结果,用多能级R矩阵理论拟合了散射质子的激发函数共振峰. 拟合结果表明,新的¹¹N能级顺序应为:1/2⁺, 1/2^－,5/2⁺,3/2⁺, 3/2^－,5/2⁺,7/2^－,同镜像核¹¹Be的实验测量结果和GCM理论计算¹¹N的能级顺序相一致.     

PION-SCATTERING FROM VIBRATIONAL NUCLEUS

We calculate the angular distributions of elastic and inelastic scatterings from vibrational nuclei by using optical potential. The neutron and proton transition densities can be studied by comparing the π⁺ and π^－ scattering on the nucleus. The importance of the virtual excitation of vibrational levels in calculating the differential cross section is discussed.     

THE COULOMB DISINTEGRATION CROSS-SECTION AND DECAY RATE OF THE SPIN (0－3/2) ELECTROMAGNETIC BOUND SYSTEM

In this paper, the coulomb disintegration cross-section and decay rate of the atom (π⁺Ω^－) are calculated by using perturbation expansion of the quantized composite field theory and relativistic B-S wave function for spin (0－3/2) electromagnetic bound system. The disintegration cross-section of the high energy atom (π⁺Ω^－) in screened coulomb field of nuclei is about σ=Z^4/3×2.9×10^－18cm², and the calculation result of the decay rate is w[(π⁺Ω^－)→π⁺Λ⁰K^－]/w[Ω^－→Λ⁰K^－]=1+O(α).     

PSEUDOSCALAR MESON-MESON POTENTIALS IN THE QUARK MODEL

We calculate the short range part of π⁺-π^－,K⁺-K^－,K⁺-π^－ and K^－-π⁺ potentials by using both the conventional quark-antiquark annihilation mechanism and the hybrid medium state model.The result of the scattering length for π⁺-π^－ channel favors the hybrid medium state model.     

Experimental Study of High-Spin States in Deformed Odd-Odd 180 Ir

High spin states in deformed odd-odd ¹⁸⁰Ir have been investigated using the ¹⁵⁴Sm (³¹P, 5nγ)¹⁸⁰Ir reaction through the measurements of excitation functions at 150, 155, 160, 165 and 170 MeV beam energies, K X-γ and γ-γ coincidences at 160 MeV. A new level scheme composed of 5 rotational bands has been established. According to the band structure characteristics and the deduced in band B(M1)/B(E2) ratios, the quasiparticle configurations and spin and parity have been proposed to the observed bands. The neutron AB crossing is observed at hω_c≈0.26 MeV for the π1/2^－[541]⊙ν1/2^－[521] and π1/2^－[541]⊙ν5/2^－[512] bands. This AB crossing frequency is close to that in the ν5/2^－[512] band of ¹⁷⁹Os indicating the loss of intruder nature of the π1/2 - orbit. Gradual alignment gain in both the π9/2^－[514]⊙ν7/2⁺[633] and π9/2^－ν5/2^－[512] bands is observed which is similar to the low spin anomaly in alignment in the πh_11/2,πd_5/2 and πi_13/2 bands of neighboring Ir and Re isotopes. Different alignment properties have been discussed in the framework of cranked shell model, and a larger quadrupole deformation is suggested for the bands with π9/2^－[514] orbit involved.     

NUCLEUS-NUCLEUS INELASTIC SCATTERING AND THE INFLUENCE OF PROJECTILE NUCLEI STRUCTURE AT HIGH ENERGIES

On the base of Glauber's theory, nuclei-nuclei inelastic scattering amplitudes are given by using the rigid projectile approximation. Inelastic scattering differential cross sections of α+C¹² at 1.37GeV with 2⁺(4.43MeV) and 3^－(9.64MeV) of C¹² in the final state are calculated. The influence of the different density distributions of the projectile nuclei on nuclei-nuclei inelastic scattering is discussed.     

New Nuclide 129Pm Near the Proton Drip Line

The very neutron-deficient nuclide ¹²⁹Pm was produced via the ⁹²Mo(⁴⁰Ca, p2n) reaction and identified for the first time by using the X-γ coincidence in combination with a He-jet tape transport system. From the decay of a 99keV γ ray which corresponds to the 5/2^－→1/2^－ transition in the daughter nucleus ¹²⁹Nd following the (EC+β⁺) decay of ¹²⁹Pm, the half-life of ¹²⁹Pm was determined to be 2.4(6)s.     

THE VARIATIONAL CALCULATION OF MASS GAP IN 2+1 DIMENSIONAL U(1) LGT

We present a variational calculation of 0^+－ and 0⁺⁺ glueball masses in 2+1 dimensional U(1) lattice gauge theory by using a Hamiltonian which possesses exact ground state and correct classical continuum limit.In deep weak coupling region,we obtain that am(0^+－) decreases with 1/g² exponentially and am(0⁺⁺)=2.78g².     

A NEW TRANSITION BRANCH OF THE 5.2 SEC ISOMER IN 183W

During the bombardment of 14.8MeV neutron on natural wolfram samples a γ-ray with energy 291.7keV and halflife 5.17±0.03 sec is observed. From the experimental facts it is assumed that in addition to the two well known transition branches from the decay of 5.2 sec isomer in ¹³⁸W there exists another 11/2⁺11/2[615]→5/2^－3/2[512] isomeric (E3) transition. The hindrance factor of this new transition is calculated. It is well cosistent with the general empirical rule of k^－ forbidden isomeric transition.     

EFFECT OF N PRODUCTION ON HIGH ENERGY PROTON SCATTERING BY NUCLEUS

The variable separation method of Glauber multiple scattering theory is developedto include the N^* production in the intermediate states and is used to calculate theinelastic scattering of proton by nucleus.Numerical results are compared with dataon p-¹²C^*（4⁺,14.08）at 1 GeV and it implies that the effects of N^* production tothe high-energy proton-nucleus scattering are noticeable.     

THE MASS GAP IN 2+1 DIMENSIONAL SU(3) LATTICE CAUGE THEORY

We present a variational calculation of C=+1 and C=－1 glueball masses in 2+1 dimensional SU(3) lattice gauge theory using a Hamiltonian in which the ground state is exactly known.In the range 0<1/g²≤6,we obtain good scaling behaviour am₊=36.1g² and am_－=5.98g².     

The Spin Effect of Antiproton-Nucleus Inelastic Collison

If the antiproton optical potential is inclusive of the spin orbit interaction term,the A(p,p)A* inelastic scattering not only can excited the normal parity states,but also can excited the abnormal parity states.There are also induced the polarization P_f(θ) at the inelastic scattering.In the framework of DWIA,we derived the inelastic scattering cross section (dσ/dΩ)_f,i,and polarization P_f(θ),and calculated the (dσ/dΩ)_f,i, and P_f(θ) for ¹²C(p,p)¹²C* with 2⁺,3^－ and 1⁺ states at antiproton energies of 46.8 and 179.7MeV.They fited experiment data quite well.Due to the abnormal partity states in the inelastic process have been measured,the spin orbit term can not be neglect.     

Study of ψ(2S)Decays into pπ and KK

From a study of(2S)decays into vector-pseudoscalar final states,ρπ and KK*,based on a sample of 1.27×10⁶ produced (2S) events,we have set upper limits at 90% confidence level on the branching fractions into ρπof 3.6×10^－5, into K⁺K^*+c.c.of 2.5×10^－5,and into K⁰K^*0+c.c.of 1.2×10^－4.We find that all these decays are substantially suppressed relative to the corresponding J/ψ decays in comparison with PQCD predictions.Our results confirm the MARK Ⅱ measurements at an improved sensitivity level.     

Determination of J/ψ Leptonic Branching Fraction Via ψ(2S)→π+π－J/ψ

Two processes ψ(2S)→π⁺π^－J/ψ,J/ψ→1⁺1^－ and J/ψ→anything are carefully studied to get the J/ψ leptonic branching fractions with the ψ(2S)data at BES/BEPC.The results are B(J/ψ→e⁺e^－)=(5.90±0.07±0.16)% and B(J/ψ→μ⁺μ^－)=(5.96 ±0.08±0.16)%,and B_e/B_μ is estimated to be 0.990±0.018±0.024.Assuming B_e=B_μ,the leptonic branching fraction of the J/ψ is B(J/ψ→1⁺1^－)=(5.93±0.05 ± 0. 16 )%.This result is used to estimate the QCD scale factor ∧(nf/MS) and the strong coupling constant α_s.     

Effect of σ*,φ Mesons on the Neutron Star Matter at Finite Temperature

Within the RMF approach, considering the contribution of σ*,φ mesons and baryon octet {n,p,Λ,Σ^－,Σ⁰,Σ⁺,Ξ^－,Ξ⁰}, some properties of neutron star matter have been investigated in the temperature region between 5—15MeV. It is found that when the contributions of σ*,φ mesons are included, (1) the critical baryon density decreases (but for the Λ hyperon, the effect is not obvious), but the number of hyperons increases; (2) the equation of state becomes soft at higher energy density; (3) the maximum mass decreases while the corresponding radius increases; (4) the central density, the central energy density, and the central pressure all become smaller. At T=5MeV and 10MeV and for Σ⁰,Ξ⁰,Σ⁺, the σ*,φ mesons make critical baryon density greatly decrease; but at T=15MeV, 20MeV, and 25MeV, the effect is not obvious. However, for Λ,Σ^－,Ξ^－ hyperons, at all the above temperatures, the effect is not obvious.     

A Study of the Processes of e+e－→e+e－,μ+μ－ at Large Angle and Measured Luminosities

Using the BES data collected at √S=4.03GeV.the QED processes of e⁺e^－→e⁺e^－,μ⁺μ^－ have been studied. Our measurements agree with the QED prediction,and luminosities obtained from these two final states are compatible at a level of 4%.The total integrated luminosity of 23.1pb^－1 was given for all data collected at this energy region from the calculation.     

Experimental Study of Resonance f2(1270) in the J/ψ Hadronic Decay

Based on the 2.5 million J/ψ's collected by the BES at BEPC,through the hadronic decay J/ψ→ωf₂(1270),f₂(1270)→π⁺π^－,ω→π⁺π^－π⁰,the properties of the resonance f₂(1270) are studied:its mass,width,and branching ratio.the angular distribution is fitted with maximum likelihood methood,determining its.J^PC=2⁺⁺ and giving in the first time the helicity amplitude ratios of this process as:x=0.99±0.29; y=－0.24±0.17; z₁=0.90±0.57;z₂=0.56±0.22.     

HELICITY FORMALISM OF THE ANGULAR DISTRIBUTION FOR THE J/ψ HADRONIC DECAY PROCESS

In this paper we give the helicity formalism of the angular distribution for processes e⁺e^－→J/ψ→V+X,V→P₁P₂ and e⁺e^－→J/ψ→V+X,X→P₄P₅.It provides the theoretical formula for e⁺e^－ experimental data analysis.