Meson-Nucleon Scatterings in an SU(3) × SU(3) σ Model

Meson-nucleon scatterings are investigated in an SU(3) x SU(3) a model with scalar, vector, pseudoscalar and pseudovector couplings between mesons and baryons. from the calculation of effective coupling constants, sigma terms and s-wave scattering lengths for πN and K⁺N scatterings in the tree approximation, we find that the pseudoscalar coupling dominates s- and u-channel baryon Born terms, and the cancellation between the scalar and vector interactions leads to reasonable meson-nucleon scattering properties.     

A Note on Spin of Skyrmions in the (2+1)-DO(3) Non-Linear σ Model

It is shown that, by usual definition about the Hopf term, the Skyrmions in the (2+1)-DO(3) non-linear σ model with this term have only integer spin. A modified definition about the term is suggested to make the Skyrmiona have probability to poaaeas fractional spin.     

Quantization of the O（N） Nonlinear Sigma Model

The Hamilton-Jacobi method of quantizing singular systems is discussed.The equations of motion are obtained as total differential equations in many variables.It is shown that if the system is integrable,one can obtain the canonical phase space coordinates and set of canonical Hamilton-Jacobi partial differential equations without any need to introduce unphysical auxiliary fields.As an example we quantize the O(2) nonlinear sigma model using two different approaches:the functional Schrodinger method to obtain the wave functionals for the ground and the exited state and then we quantize the same model using the canonical path integral quantization as an integration over the canonical phase-space coordinates.     

Nonlinear optical properties of LaCa(4)O(BO(3))(3)

We have grown LaCa(4)O (BO(3))(3) (LaCOB), an isostructural member of GdCa(4)O(BO(3))(3) (GdCOB) family and characterized its nonlinear optical properties. At 1064nm, d(eff) of 0.52+/-0.05 pm /V and an angular sensitivity of 1224+/-184(cm rad)(-1) for type I frequency doubling in LaCOB were determined relative to those of KTiOPO(4) , beta-BaB(2)O(4) , KD(2)PO(4) , LiB(3)O(5) , YCa(4)O(BO(3))(3) (YCOB), and GdCOB. The d(alphabetabeta) and d(gammabetabeta) coefficients of the nonlinear optical tensor for LaCOB, GdCOB, and YCOB were determined to be equivalent within the experimental uncertainty and have values of ?0.26+/-0.04?pm/V and ?1.69+/-0.17?pm /V , respectively. From phase-matching angle measurements at 1064 and 1047nm, we predict that LaCOB is noncritically phase matched at 1042+/-1.5 nm .     

Nonlinear optical properties of (B3O7)5- and (B3O6)3- groups

3 O₅ (LBO) crystal has been studied by using the bond valence theory of complex crystals. Chemical bond parameters and linear and nonlinear optical (NLO) properties of each type of constituent chemical bonds are quantitatively determined. Because of the different crystal structure characteristics of LBO from those of β-BaB₂O₄ (BBO), the two anionic groups, (B₃O₇)^5- in LBO and (B₃O₆)^3- in BBO, play different roles in contributions to their own total NLO tensor coefficients of LBO and BBO, respectively. By comparison, we find that planar (B₃O₆)^3- groups are the ideal structure model, leading to little cancellation of contributions of each kind of bond in these groups, and this gives us a useful guide to design new NLO materials in the future. Received: 24 January 1997/Accepted: 27 March 1997     

THE FACTORS FOR THE EMC PHENOMEKON AND THE RATIO RA=(σL/σT)A

The three factors are discussed which may be related to the EMC phenomenon directly, and it is tried to understand the new results on the ratio R^A=(σ_L/σ_T)_A. It is also pointed out that shadowing cannot match the obvious deviation in the small x region between the data obtained by the two categories of experiments PA and eA.     

Study of the Binding Energy of Relativistic Nuclear Matter in the Relativistic σ-ω-π Model

A relativistic σ-ω-π model is proposed to calculate the binding energy of relativistic nuclear matter. We put emphasis on the relativistic particle-hole, delta-hole excitation of pion propagator in nuclear matter. The renormalization of the nucleon self-energy in nuclear matter is made for the pseudo-vector πNN and πNΔ couplings by introducing corresponding form factor and by dispersion relation. We find that the density dependence correction to meson-NN coupling constants is very important to saturate the binding energy of nuclear matter. The density dependence correction to πNN and πNΔ coupling constants has the effect of softening the EOS of nuclear matter.     

The Fibre Bundle Formulation of σ-Model and SUSY σ-Model

In this paper, we present an analysis of the general symmetry properties of some physical systems, where especially the method of h_μ(x), k_μ(x) decomposition of connection is used. Then we reformulate the σ-model and the SUSY σ-model in the framework of fibre bundle theory. By comparisons, we obtain the SUSY partner of "linearized" equation or Lax pair of σ-model.     

Pion Propagator in the Chiral σ Model of Nuclear Matter

Pion propagator is studied in the chiral σ model at the zero temperature nuclear matter. Due to the tachyon pole of the π and σ tree approximation propagators, only the nucleon polarization insertion loop (explicitly density dependent part and vacuum fluctuation part) can be fully included into the pion propagator. The vacuum fluctuation as a function of nucleon effective mass or pion external momentum (after Wick rotation) is negative for most of the cases. So the variation of nucleon effective mass is restricted to a very limited region where is free of pion condensation (otherwise the nucleon energy density will be complex). The effect of NN short-range correlation is calculated and it is very small for low momentum.     

一种新型晶体GdCa4O(BO3)3的非线性光学性能研究

计算和测量了ＧＣＯＢ晶体的相位匹配曲线,理论计算与实验测量结果符合的很好。用电光调Ｑ的Ｎｄ：ＹＡＧ激光器对５ｍｍ和匠ＧＣＯＢ晶体进行了倍频研究,得到了２６．７％的倍频转换效率。并与同样长度的ＢＢＯ晶体进行比较,得出了ＧＣＯＢ晶体的有效非线性光学系数接近ＢＢＯ晶体的有效非线性光学系数的结论。     

Analytic Study of XY-Ising Model

We apply the variational cumulant expansion to study the phase transition of a two-dimensional coupled XY-king model. This model can describe several different systems with underlying continuous and & symmetries. We calculate the free energy, internal energy and specific heat to the third-order approximation with the trial action of two variational parameters. A comparison with Monte Carlo data is also presented.     

Poisson-Lie Structure of O(3)-σ Model in Terms of Moving Local Frame

We discuss the Poisson-Lie structure of the integrable nonlinear O(3)-σ model in terms of moving local flame. The corresponding T, s matrices are given out explicitly. The fielddependent terms in r, s matrices appear to be associated with the Riemannian connection of the target manifold.     

[Fe3O（Ala）6（H2O）3]（ClO4）7和[Fe3O（Gly）6（H2O）3]（NO3）7·3H2O的顺原共振谱及变温磁化率研究

本文通过对[Fe 3O(Ala) 6(H 2O) 3](ClO 4) 7和[Fe 3O(Gly) 6(H 2O) 3](NO 3) 7·3H 2O的ESR谱的解析及变温磁化率的研究,得出它们的ESR谱具有各向同性的特点;朗德因子分别为2.019和1.997;两种配合物中铁离子间有反铁磁相互作用.     

非线性光学晶体硼酸镧钠(Na_3La_9B_8O_(27))的光谱研究

测量了Na3La9B8O27晶体在紫外-可见光-红外波段的透射光谱和反射光谱,分析得到其在上述波段的吸收光谱。在波长400nm~2000nm范围内,透射比超过80%,禁带宽度为3.93eV,没有明显的缺陷和杂质吸收。测量了该晶体在太赫兹波段的时域光谱,分析得到其在上述波段的吸收光谱、折射光谱,且通过光学常数之间的关系,得到其介电常数ε曲线。在0.3~1.5THz内吸收小于10cm-1。在0.3~2.4THz内,介电常熟实部ε1成近似线性递增趋势,介电常熟虚部ε2小于0.03。     

σ-ω Mixing for the Collective Excitation Spectra of σ, ω Mesons in Nuclear Matter

We study σ-ω mixing on the σ and ω propagators in two ways. The collective excitation spectra of σ,ω mesons are calculated by using these propagators. We find that the two ways of σ-ω mixing give very similar collective excitation spectra in the time-like region.     

QCD Correction to σ(e+e-→ZH→Zbb)

We study the QCD corrections to the calculated values of σ(e⁺e^-→ZH→Zbb), and find that for M_H<100 GeV, the process can be measured at the LEP energy to extract information of Higgs and the QCD corrections are negligible, namely the tree-level calculation is sufficiently aciurate for the energy range, while for M_H > 100 GeV, the Higgs-involved subprocess can only be investigated at NLC, and then the QCD correction becomes as large as 45%. For M_H > 2mt, considering the subprocess e⁺e^-→ZH→Ztt, the QCD corrections are also important and must be taken into account for the cross section evaluation.     

A New(γ_A,σ_B)-Matrix KP Hierarchy and Its Solutions

A new(γA,σB)-matrix KP hierarchy with two time series γA and σB,which consists of γA-flow,σB-flow and mixed γA and σB-evolution equations of eigenfunctions,is proposed.The reduction and constrained flows of(γA,σB)matrix KP hierarchy are studied.The dressing method is generalized to the(γA,σB)-matrix KP hierarchy and some solutions are presented.     

[Fe3O(Ala)6(H2O)3](ClO4)7和[Fe3O(Gly)6(H2O3)(NO3)7)·3H2O]顺磁共振谱及变温磁化率研究

本文通过对[Fe 3O(Ala) 6(H 2O) 3](ClO 4) 7和[Fe 3O(Gly) 6(H 2O) 3](NO 3) 7·3H 2O的ESR谱的解析及变温磁化率的研究,得出它们的ESR谱具有各向同性的特点;朗德因子分别为2.019和1.997;两种配合物中铁离子间有反铁磁相互作用.     

Skyrme Sphalerons of an O(3)-σ Model and the Calculation of Transition Rates at Finite Temperature

The reduced O(3)-σ model with an O(3)-σ→ O(2) symmetry breaking potential is considered with an additional Skyrmionic term, i.e. a totally antisymmetric quartic term in the field derivatives. This Skyrme term does not affect the classical static equations of motion which, however, allow an unstable sphaleron solution. Quantum fluctuations around the static classical solution are considered for the determination of the rate of thermally induced transitions between topologically distinct vacua mediated by the sphaleron. The main technical effect of the Skyrme term is to produce an extra measure factor in one of the flucuation path integrals which is therefore evaluated using a measuremodified Fourier-Matsubara decomposition (this being one of the few cases permitting this explicit calculation). The resulting transition rate is valid in a temperature region different from that of the original Skyrme-less model, and the crossover from transitions dominated by thermal fluctuations to those dominated by tunneling at the lower limit of this range depends on the strength of the Skyrme coupling.     

Faddeev-Jackiw Quantization and Its Application to the Linear σ Model for Disoriented Chiral Condensates

The equivalence between the Faddeev-Jackiw formalism and Dirac-Bergmann algorithm is proved. A two-dimensional constrained system and a charged vector field are quantized in the Faddeev-Jackiw formalism. This symplectic method is technically developed, without recourse to Hamiltonian or Lagrangian, to quantize systems whose equations of motion are known. Examples are given to show this role. For constructing quantum approaches to the disoriented chiral condensates, the linear σ model is quantized in the instant form, light-cone form and covariant form.