α PARTICLES EMITTED IN THE REACTION OF 12C ON 209Bi

The energy spectra and angular distributions of alpha particles emitted in the reaction of 12C on 209Bi in the energy range 61.1—73.0 MeV were observed.The △E— E detector system was used to separate alpha particles and other particles emitted in this reaction.The results can be interpreted in terms of the reaction mechanism,in which a 8Be cluster is transfered from the projectile to the target.Good agreement has been obtained between the cross section for the production of the direct alpha particles and that of the heavy residue 217*Fr which,left in the ground state after evaporation of 2 neutron's,decays into 211At by alpha emission.The experimental energy spectra and angular distributions have been fitted by a semi-classical formula for the differential cross section per unit solid angle and energy interval.     

23Na（p,α）20Ne反应中几个非孤立共振的研究

本工作测量了²³Na（p,α₀）²⁰Ne_g.s.反应在 E_p=1—2.5MeV 能量范围内和θ_L=30°,150°时的激发函数,还测量了²³Na（p,α₁）²⁰Ne_lst,反应在上述能量范围内和θ_L=30°时的激发函数.对2.171 MeV 共振,在12个角度上测量了（p,α₀）的激发函数,并由激发函数求得了多个角分布,另外在一个固定能量上（150°激发函数的共振峰上）测量了（p,α₀）反应的角分布.对2.117 MeV 共振,在二个固定能量上（150°激发函数的共振峰上和其高能端的半高点处）测量了（p,α₀）反应的角分布.对2.075 MeV 共振,在16个角度上测量了（p,α₀）反应的激发函数,并由激发函数求得了角分布.这三个共振的角分布不是90°对称的,并且共振峰的峰位与角度有关.用复合核理论对它们进行了讨论.     

STUDY OF ANGULAR DISTRIBUTION OF THE SCATTERING OF 31.2 MeV α PARTICLE BY THE NUCLEUS 10.11B

Angular distribution of the scattering of 31.2 MeV-α-particle by the nucleus ^10,11B is measured. Our results show that there is anomalous phenomenon in the case of ¹⁰B but there is not in ¹¹B. Calculations and analysis are made with the optical model adding the Regge-Pole model. The results show that for the nucleus of 1p-shell, such as α+¹⁶O, the result of the calculation agrees very well with the experimental measurements but it fails in α+¹⁰B. As to the analysis with the double v-power optieal model for α+¹⁶O, the agreement is somewhat a little worse than the former's and the result for α+¹⁰B agrees only qualitatively with the experimental measurement. It is well known that the analysis with these models for α+⁴⁰Ca agrees very well with the experimental data. Thus we may come to the conclusion that the mechanism of ALAS of the nucleus of 2s-1d shell is different from that of 1p-shell, and the mechanisms of ALAS of the nuclei of 1p-shell are also different.     

THE RESONANCE OF THE CHAIN STRUCTURE STATES IN A(α,αx)B TYPE THREE-BODY REACTIONS

In this Paper a calculable three-body T matrix with compact kernel is obtained by using multiplier's methods. The formulations for calculating the A（a, ax）B type three-body reaction trans-tion amplitudes are presented when plane wave or distorted wave is used for the incident and outgoing states. This T matrix also includes the resonance terms of the three-body chain struc-ture states besides quasi-free scattering terms and final states interaction terms. A calculable formulation for the resonance energy of chain structure states is presented when it is expanded approximately into two two-body bound states. For ⁸Be and ⁶Li as target nuclei, the resonance energies are calculated. The results are in good agreement with the experimental values and the theoretical values of a mole-cule-like model. In order to check this kind of resonances, some experiments are proposed.     

A TWO-NUCLEON MODEL OF THE（p,π-） REACTION

In this paper,we suggest a two-nucleon model of the A（p,π^-） B reaction.Areduced formulation of the reactoin amplitude and a relation between the reactionamplitude and the nuclear structure are given.The differential cross section of ¹³C（p,π^-）¹⁴O_g.s,at E_P=185 MeV is calculated in the plane wave approximation.The results+s can explain the experimental data qualilatively.     

CROSS SECTION MEASUREMENT FOR THE REACTION 56Fe（n,p）56Mn

The cross section measurement for the reaction ⁵⁶Fe（n, p）⁵⁶Mn was made using the activation method from 12 MeV to 18 MeV. The absolute cross section was determined at 14.61±0.20 MeV, the value obtained was 108.0±2.7mb. The associated particle method was used to determine the absolute neutron flux and compared with the recoil proton telescope. The agreement between both methods appeared to be within 1—2%. The resulting ⁵⁶Mn activity was measured by using a φ10×7.6cm NaI （Tl） scintillation counter. The counting efficiency of the counter was achieved by means of a standard ⁵⁶Mn source calibrated by the 4πβ-γ coincidence method. The result measured was compared with existing data.     

THEORY OF （π+,d） REACTION

In this paper the DWBA cross section formula for the（π⁺,d）reaction is deri-ved in the model of one-nucleon absorption of pion,and the differential cross sectionsfor ¹²C（π⁺,d）¹⁰C_g.5.2+reactions are estimated in PWBA.This kind of reaction isregarded as a worthnoting one for the studies of π absorption processes and the nu-clear pair structure.     

THE EFFECTIVE POTENTIAL BETWEEN QUARKS TO THE ORDER OF υ2/c2

We analyse the necessity and possibility of introducing an axial vector piece into the effective potential in order to cancel the spin-orbit interactions and the problems related thereby.

     

HADRONIC PRODUCTION OF J/ψ、ψ′(3684) AND THE CONTENT OF THE CHARMED STRATONS IN THE SEA OF THE STRATONS

Hadronic production of J/ψ、ψ′(3684) particles is discussed in this paper on thebasis of reference [1] after considering the massive effects of the charmed straton.The results of [1] are improved.With the aid of the decay of ψ″→DD and the effective coupling constant between ψ″(3772) and the charmed straton we estimate that the content of the charmed stratonin the sea of the stratons is 0.41% of the ordinary stratons at most.     

STUDY OF THE MECHANISM OF 12C（d,d）12C AND 12C（d,p）13C* REACTIONS

A formalism for studying the interference between the direct reaction and the compound resonance processes is presented by the S-matrix theory; The mechanism of ¹²C（d, d） ¹²C, ¹²C（d, p₁） ¹³C* and ¹²C（d, p₂） ¹³C* reactions in the energy range E_d=1.63 MeV to 2.05 MeV is analysed.Te results show that: the interference between these two processes exists; and the quantitative relation between them is given. While the parameters of direct reactions and compound resonance processes, particularly for four resonance states with E_d=1.726, 1.767, 1.792 and 1.86 MeV are determined.     

THE MECHANISM OF THE REACTION 141pr(n,α)138La AT En=14 MeV

The energy spectra of the alpha particles from the reaction ¹⁴¹Pr (n, α) ¹³⁸La at 0°, 30°, 60°, 120°, 150° and 180° are measured and the angular distributions of the alpha particles are given. It shows that the predominant mechanism of the reaction at En=14 MeV is precompound emission.     

SU（4）×S3α SCHEME OF STRATON MODEL AND THE NEWLY DISCOVERED HEAVY PARTICLE γ（9.5）

In this paper, the possibility that the newly discovered heavy particle γ （9.5） is a colour excited state of mesons in the SU（4）×S₃^α scheme of straton model is discussed. We point out that in the γ region, there are three colour excited states appearing as two peaks with mass difference about 0.5 GeV. The leptonic decays, hadronie decays, radiative decays, hadronic decays with electromagnetic interaction of the second order and the production behavior of γ are discussed. This model also predicts that many colour excited states of mesons accompanied with γ should exist with masses around 9.5 GeV and at least four weakly decaying particles should exist.     

ASYMPTOTIC FREEDOM AND THE WAVE FUNCTIONS AT THE ORIGIN AND THE ENERGY LEVELS OF THE J/ψ AND THEY

On the basis of phenomenological quantum chromodynamics (QCD), a nonre-lativistic linear and Coulomb-like potential describtion of the strong interaction be-tween quarks is assumed and it is considered that the effective quark-gluon coup-ling constant approaches the asymptotically free limit of QCD. The cloice of thepotential parameters is so made as to fit the experimental values of the wave func-tions at the origin as well as the masses of the J/ψ and the γ Following the calcu-lation referring to the ψ′and the γ′, we acquire a consistent explanation for boththe relative values of the wave functions at the origin and the experimental mass asdifferences of these particles.     

Experimental Study on 22Na(p,γ)23Mg Reaction

The reaction of ²²Na(p,γ)²³Mg has been investigated at the Radioactive Ion Beam Line in Lanzhou(RIBLL) using a radioactive beam ²³Al. The β⁺ delayed proton decay spectrum has been measured with the TOF-ΔE method and zero degree detectors. The half life of ²³Al is determined to be T_1/2=(476±45)ms by using a time scaler combined with the precision pulse generator,which is consistent with the other group's result of (470±30)ms. The known β⁺ delayed protons at E_r=0.216,0.278,0.438,0.479MeV have also observed in the experiment. The resonance strength of isospin analog state (IAS) is calculated. The resonance intensity of IAS is (11.4±6.0)meV. A new energy level of β⁺ delayed proton decay has been identified at E_x=8.916MeV,and their relative intensity also been obtained.     

THE DIFFICULTY OF THE DECAY τ→πντ AND SPIN 3/2 HEAVY LEPTON

We discuss the suppression of the decay of heavy lepton τ into πv_τ,by assuming that τ and/or v_τ carry spin 3/2. For the case of spin 3/2 T and spin 1/2 v_τ, using the weak current ψ_μ^(τ)(a+b_^γ5)Ψ^(v_τ)we find that the πv_τ decay channel relative to the v_τv_ll^-channel is suppressed 12/5 times, while other decay channels are not changed appreciably. △R=σ（e⁺e^-→τ⁺τ^-）/σ（e⁺e^-→μ⁺μ^-） is also discussed.     

THE STUDY OF α-EMISSION INDUCED BY 16O ON 27Al

The α-particles induced by 84.5MeV and 62 MeV ¹⁶O on ²⁷Al are measured using ΔE-E semiconductor telescope. The energy spectra, the angular distributions, the contour plot of d²σ/dE﹒dΩ in the E-θ plane of the emitted α particles and the variation of the nuclear temperature with the emission angles are obtained. The mechanism of the direct α particles is discussed.     

WHAT IS THE NATURE OF THE NEWLY DISCOVERED HEAVY PARTICLE γ(9.5)

In this paper, we discuss the nature of the newly discovered heavy particle Y（9.5）. Five possibilities of experimental criteria are analysed. We show that if Y is a heavy photon, an intermediate boson, a bound state of straton-antistraton or a hadron without valence stratons, and all the Γee will differ by several orders of magnitude and can therefore be discriminated easily in e⁺ e^-collision experiments. The width value Fee and its ratio of γ to γ' are not identical for the case of colour excited states of meson and the case of bound states of the new straton-antistraton. The masses of other existing new particles can also be predicted. In particular, the masses of weakly decaying heavy particles are not the same for these two cases, which may be regarded as a criterion to discriminate between these two cases. We have also discussed the main decaying properties of γ for these five possibilities.     

16O(16O, 12C)20Ne α转移反应机制的研究

¹⁶O(¹⁶O, ¹²C)²⁰Ne反应微分截面中的振荡结构在核分子轨道理论框架下, 基于由共价道到离子道的α转移机制得到满意的解释.     

A MEASUREMENT OF THE ELASTIC SCATTERING FOR REACTION 12C+28Si AT ENERGIES 56MeV—69MeV

The angular distributions of the elastic scattering for reaction ¹²C+²⁸Si have been measured at the energies 69.5MeV, 66MeV, 59MeV, 56MeV using the large area position sensitive ionization chamber. The experimental data are fitted by use of the optical model. The probable reasons of the enhancement and oscillation of the elastic scattering angular distribution are discussed.     

THE DETERMINATION OF ENDPOINT ENERGY FOR 235Th β-DECAY

Sources of ²³⁵Th were prepared by 14MeV neutron irradiation of Uranium and radiochemical separation.The β-spectra and γ-spectra were measured.The endpoint energy for ²³⁵Th β-decay was obtained to be 1.44±0.04MeV.Thus Q_B of ²³⁵Th was determined to be 1.47±0.07MeV.