THE MOMENT OF INERTIA IN THE INTERACTING BOSON-FERMION MODEL

For a system described by the interacting boson-fermion model (IBFM),we construct the intrinsic states and study the moment of inertia of deformed odd-A nuclei in terms of the selfconsistent cranking calculation.An approximate analytic method for the energy spectrum is presented in the general cases where the IBFM Hamiltonian does not have dynamical symmetry.The rationality of this method is also discussed by taking ^153,155,157Eu isotopes as examples.     

INTERACTING BOSON MODEL FOR ROTATIONAL STATES OF NEGATIVE PARITY

In this paper, rotation of the system consiting of N—1 (sd) bosons and one (pf)boson is discussed on the assumption that the SU(3) limit is just the rotational limit.Using group-theoretical methods, we have given rotational spectra of negative parity,and have derived the analytic expressions of the reduced matrix elements of the E3transition from the v₀-band (K^π=0^-) to the ground band. In terms of the inegualityof the intensities of (sd)-(sd). interaction and (sd)-(pf) interaction, the differencebetween the parmeters of positive-parity bands and those of negative-parity bands areexplained qualitatively.     

Rotational Bands of Some Neutron Deficient Odd-A Pt Isotopes in Particle-Triaxial-Rotor Model

Theoretical calculations are performed for neutron deficient Pt isotopes ^177pt and ^175,173,171 Pt in the particletriaxial-rotor model with variable moment of inertia. The obtained energy spectra agree with experimental data quite well. The calculated results indicate that all these nuclei are in triaxial rotation with ^177pt; being in prolate and ^175,173,171pt in oblate. Several levels are predicted for the 13/2^＋ band in ^169pt.     

Gluon Exchange Potential and Cross-Section for pp→ΛΛ Proce

One and two-gluon exchange potentials (OGEP and TGEP) relevant to the pp→ΛΛ transition process are derived from the S-matrix in the a　roximation of order p²/m². An effective transition potential obtained from these gluon exchange potentials by the constituent quark model is employed to calculate the differential and total cross-sections for the pp→ΛΛ reaction in the plane wave Born Approximation.The calculated result shows that the relativistic correction terms in the OGEP and TGEP give considerable improvements on the cross-section in comparison with the previous calculations performed by making use of the OGEP given in the extremely non-relativistic a　roximation.     

Studies of the Low-Lying States in 157,159Tm

Properties of the low-lying positive-parity states in ^157,159Tm are investigated ly using the triaxial rotor plus particle model with the variable moment of inertia (VMI) of the core.The good agreement between theory and experiment shows that ¹⁵⁷Tm and ¹⁵⁹Tm may be triaxiality.Furthermore,it is suggested that an excitation rotational band in ¹⁵⁷Tm probably already exists in the experimental data.     

CALCULATION OF THE EFFECTIVE MOMENT OF INERTIA OF FISSIONING NUCLEI AT SADDLE POINT

The effective moment of inertia,charge density distributions of the fissioning nucleus ¹⁷⁰Yb and ²⁵⁴Fm at saddle point are calculated by using the continuous medium model with variable densities.     

应变晶体的弹性偶极子模型

将物体视为一弹性连续介质,其中任一处在应变状态的体积元以一弹性偶极子模拟之,本文给出了它的等效偶极矩的表示式,并将其划分为与此体积元及其周围基体的固有性质有关的永久偶极矩和决定于介质所处的应变状态的感生偶极矩两部分,它们分别使弹性介质具有顺弹性和介弹性。本文给出了在各向同性的弹性连续介质中弹性偶极子所产生的位移场的表示式,以及在考虑到其他应力源的强度和偶极子矩间存在着相互弛豫作用的情况下,弹性偶极子与其他应力场间相互作用的式子,它是Kroner公式加上高级修正项,将此模型用于讨论熟知的Cottrell气团和两对称中心间的相互作用时,得到与前人一致且更为细致的结果。 关键词：     

Determining the Spin-Parity of the Boson Resonance X in the Process J/ψ→X+f0 (980) by Using the Generalized Moment Analysis Method

The processes J/ψ→X+f₀ (980), X→K⁺ K^－,f₀ (980)→π⁺+π^－ are discussed using the generalized moment analysis method. It is suggested that in terms of the obtained moment expressions the spin-parity of the boson resonance X can be determined by further measurements.     

Investigation of the Type of Quadrupole Pairing Force in Superdeformed Nuclei

The variations of moments of inertia of superdeformed (SD) bands ¹⁹⁴Hg(1)and ¹⁹²Hg(1) with angular momentum (rotational frequency) are investigated using the particlenumber conserving (PNC) method for treating the cranked shell model. Calculations show that if both the monopole and Y₂₀ quadrupole pairing forces are taken into account, the observed co variation of the moments of inertia of ¹⁹⁴Hg(1) and ¹⁹²Hg(1) can be reproduced very well both in the low-and high- ranges, in particular the J⁽²⁾ downturn of ¹⁹⁴Hg(1) and the flattening in J⁽²⁾ of ¹⁹²Hg(1) at>0.40MeV. On the contrast, the calculated J⁽²⁾'s with the Y_2±1 or Y_2±2 quadrupole pairing forces are in disagreement with the experiments. The microscopic mechanism of the co variation of J⁽²⁾ is clearly exhibited in the PNC calculation (the contributions to J⁽²⁾ from various major Shells and individual cranked Nilsson orbitals, the occupancy of each cranked Nilsson Orbital etc). The variation of moment of inertia is the result of the competition among the shell effect (single particle motion in a deformed potential), pairing correlation, Pauli blocking effect and Coriolis (anti-pairing) interaction.     

THE BARYON MAGNETIC MOMENT IN A QUARK-DIQUARK MODEL

It is pointed out that a quark-diquark model might improve the fit to baryonicmagnetic moments with a minimum of parameters. A calculation by using this modelgives good agreement with the magnetic moment of ∑⁺ and E^0_.     

A DYNAMICAL MODEL FOR THE GLUON DISTRIBUTION FUNCTION

In this paper the forms of the gluon distribution function at different Q² are discussed with the aid of the three-quarks model associated with dynamical calculations of QCD (the LLA approximation). The Buras-Gaemers parametrization is improved and the gluon distribution functions are obtained. It can be described by a simple parameter form: xG(x, Q²)=xG₁(x, Q²)+xG₂(x, Q²)=[1+B(s)]1(Q²)>2(1-x)^[B(s)]+[1+D(s)]2)>(1-x)^D(s), The form satisfies the QCD evolution equations and does not contradict evidently with existing experimental data. Then the properties of the constituent gluons in a nucleon are analyzed on these basis and it is indicated that the gluon distribution function could be considered as to be made of two different parts-soft and hard parts.     

Double-Blocking Effects in Odd-odd Superdeformed Nucleus 194Tl

Six superdeformed bands of odd-odd nucleus ¹⁹⁴Tl in A～190 mass region are studied using the particle-number conserving method for treating the cranked shell model with pairing interactions. Calculated results agree with experiments very well. Based on our calculation the configurations of the six superdeformed bands are assigned and the influence of blocking effects of proton and neutron on moments of inertia is investigated in detail. The variation of moments of inertia with rotational frequency is mainly attributed to the intruder shells (neutron N=7 and proton N=6), whereas the contributions to moment of inertia from other shells remain almost unchanged with rotational frequency.     

A Study for Nuclei 166Hf94—170Hf98 Using Cranking Shell Model with PNC Method

The properties of the band in even nuclei of ¹⁶⁶Hf₉₄—¹⁷⁰Hf₉₈ are investigated using cranking shell model with PNC method. The band crossing frequency, the interaction intensity between yrast and yrare bands, the aligned momentum, and the moment of inertia are calculated. The comparison between the calculation and experimental data shows a good agreement with each other if Lund systematic parameter is used for the Nilsson potential.     

QUANTUM EXPANSION AROUND THE VERTEX TYPE SOLUTION OF N-O MODEL

By means of the generalized method of quantum expansion and the general treatement for quantization of gauge fields recently proposed by S. N. Gupta, we calculate the quantum expansion around the vertex type solution of N-O model. Under special conditions, the eigen-value of the energy of quantum excitation can be obtained.It is shown that both P^o（-1） and II^o （-1） are equal to zero in the case we considered. As a result, our calculations are greatly simplified.     

Experimental Evidence for the Superdeformation in 81Rb

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.     

COULOMB CORRECTION OF THE p-4He LOW ENERGY SCATTERING PHASE SHIFTS

A simple approach of Coulomb correction to the p-⁴He low energy scattering phase shifts is proposed,in which the channel radius of each partial wave is taken as an adjustable parameter.By using the Coulomb correction the n-⁴He scattering observables predicted from p-⁴He scattering phase shifts are in excllent agreement with experiment.Our calculations show that the neutron polarization depends sensitively on the channel radius of p waves and the obtained channel radius are adeguate to the different sets of phase shifts.     

INTERACTING BOSON-FERMION MODEL AND

A model Hamiltonian of interacting Boson-Fermion system is given and this modelHamiltonian is solved with siniority v≤2. The calculation shows that the back-ben-ding phenomana can be well discribed.     

On the Asymptotics of the Finite-Perimeter Partition Function of Two-Dimensional Lattice Vesicles

We derive the dominant asymptotic form and the order of the correction terms of the finite-perimeter partition function of self-avoiding polygons on the square lattice, which are weighted according to their area A as q^A, in the inflated regime, q >1. The approach qM 1⁺ of the asymptotic form is examined.