在巴黎势的波函数中氘核的形状因子A(Q~2)(英文)

在非相对论的框架内和应用描述了高动量过程的巴黎势所产生的氘核的波函数,计算了氘核的电磁形状因子A(Q~2)。A(Q~2)因子化为氘核的结构函数Z(t)和偶极形状G_D(t)之积。结构函数Z(t)是用巴黎势的波函数做数值计算而得到的。对A(Q~2)的预言跟实验数据的分析非常一致,这一对实验结果的成功描述说明:氘核形状因子A(Q~2)这一简单的理论描述是非常成功的,并且可以用到氘核的其他静态性质的研究。     

Would the peak value of the electromagnetic quadrupole form factor of the deuteron determine the percentageD-state?

It is shown that short range unitary transformations on the deuteron wave function of the super-soft-core potential of de Tourreil and Sprung, which fix the percentageD state of the deuteronP _D, do not simultaneously fix the peak valueM of the electromagnetic quadrupole form factor of the deuteron within small error bars, even when the transformed wave functions are required to fit the quadrupole moment and the electric form factor of the deuteron within narrow limits. However there is a strong correlation betweenP _D andM ² for realistic interactions whose deuteron wave functions are suppressed at short distances.     

High momentum component in the deuteron

The high momentum component in the deuteron, which stems from the short range part of the nucleon-nucleon interaction, is studied in they-scaling function and the structure functionF ₂ of the deuteron. We use not only some non-relativistic wave functions but also relativistic ones. It is shown that the relativistic mechanism or a six-quark state in the nucleon-nucleon interaction yields a large high momentum component.     

Three-Dimensional Low-Momentum Interaction in Two-Body Bound State Calculations

The deuteron binding energy and wave function are calculated by using the recently developed three-dimensional form of low-momentum nucleon–nucleon (NN) interaction. The homogeneous Lippmann–Schwinger equation is solved in momentum space by using the low-momentum two-body interaction, which is constructed from Malfliet–Tjon potential. The results for both, deuteron binding energy and wave function, obtained with low-momentum interaction, are compared with the corresponding results obtained with bare potential.     

The deuteron and its magnetic moment the effects of non-local nuclear forces and of unitary transformations

The deuteron theory is renewed and completed for non-local Hamiltonians. A method to calculate deuteron wave functions is given. The formula for the current density and the magnetic dipole moment of a non-local potential is derived, and applied to the GCT, GT, and HJ-potential. The effects of a unitary transformation on the deuteron data — electric quadrupole moment, magnetic dipole moment, and radius — are shown. For the numerical calculations the Ristig-Kistler transformation and the HJ-potential were used. It is shown that an overall fit cannot be reached.     

Deuteron Photodisintegration in the Diagrammatic Approach

Photodisintegration of the deuteron below the pion-photoproduction threshold is considered in the framework of the diagrammatic approach. The deuteron wave function, the final-state N–N interaction and meson-exchange currents are constructed from the nonrelativistic versions of the Bonn OBE potential. A detailed comparison with the existing data is made. It is shown that the model gives a satisfactory agreement with the experimental data. Possible sources for the remaining disagreements are discussed. Received June 10, 1994; revised September 25, 1994; accepted for publication November 18, 1994     

Deuteron size effects on its elastic scattering from1H and4He

The effect of change in deuteron size on its elastic scattering from protons and alphas is investigated by varying the Hulthen parameters of the deuteron wave function in the scattering process. The cross sections forp-d scattering, calculated in the Born approximation, are found to increase substantially at backward angles even when the deuteron size is reduced by a small amount, whereas the shape of the angular distribution does not change significantly. For theα-d elastic scattering, interaction potential is obtained by folding the deuteron wave function and the optical potential for nucleon-scattering. The cross sections calculated atE _d = 13·7 MeV, shows that the first minimum around Θ_cm = 60° is deepend as the deuteron size is reduced, while at 52 MeV bombarding energy, the size effects are not very distinct. These observations are useful in the interpretation of deuteron cluster knockout reactions.     

The Triton from the Reid93 Potential in the UPA

The unitary pole approximation (UPA) provides an effective means to construct a rank one separable potential for calculations in which one requires a simple representation of the deuteron and/or triton ground-state wave function. By construction the deuteron wave function and the ¹S₀ anti-bound state wave function of the original potential are reproduced. We report results for the corresponding triton ground state. We choose to utilize the realistic Reid93 potential for this purpose. The Reid93 potential, generated by the Nijmegen group, is a Reid-like, partial-wave local potential that produces a χ² representation of the nucleon–nucleon (NN) scattering data that is as precise as an NN partial-wave analysis. Results for properties of ²H and ³H from the UPA are compared with those for the original potential. To further illustrate the precision of the method, results for properties of the deuteron and triton from the UPA are also compared with those for the original Reid68 potential.     

Electric-dipole sum rule in nuclear matter

The enhancement factor K in the electric-dipole sum rule for some realistic models of symmetrical nuclear matter is calculated using variational theory. The nuclear-matter wave function used contains central, spin, isospin, tensor and spin-orbit pair correlations. The non-central correlations, particularly the tensor one, give the major contribution to K. At experimental equilibrium density K. turns out to be ≈ 1.8, of which 65% comes from OPEP and 30% from the short-range part of the interaction. The two-pion-exchange three-nucleon interaction contributes ≈ 0.2% and is cancelled, to a large extent, by the contribution due to the intermediate-range two-body potential. The relationship of the summed oscillator strength with the effective mass is also discussed.     

On the six-quark structure in the deuteron form factor

The charge and quadrupole deuteron form factors are investigated in a wide region of momentum transfer taking into account the deuteron six quark structure. It is shown that the contribution due to the antisymmetrization of the wave function with respect to quark variables is small and the contribution of the “true” six quark admixtures plays the leading role in the region of large momentum transfer.     

Corrections to the deuteron static moments

We show results for the corrections to the deuteron quadrupole and magnetic moments due to relativistic effects, mesonic exchange currents, higher order terms in the single-particle current and contributions from the spin-orbit and quadratic spin-orbit parts of the NN interaction. We have also considered estimates of the contributions from the isobar components of the deuteron wave function. We discuss the significance of our results in the determination of the spatial behavior of the deuteron wave function and, by extension, of that of the NN potential.     

An approximate three-body theory of deuteron stripping

A treatment of deuteron stripping is developed in which the three-body effects associated with deuteron break-up in the nuclear field are included explicitly. The essence of the method is the choice of a convenient discrete set of n-p eigenfunctions as a representation of the three-body continuum effects. This approach leads to a distorted wave stripping matrix element similar to that of the DWBA, except that the elastic deuteron wave is replaced by a three-body wave function given as the solution of a set of coupled two-body Schrödinger equations. The adiabatic theory of Johnson and Soper appears as the solution in a suitable first approximation. This new formalism should prove useful in the evaluation of corrections to three-body models of the deuteron-nucleus system, in particular those models in which the nucleon-target interaction is represented by a complex local optical potential.     

Neutron structure function and deuteron EMC effect

Using the impulse approximation, a relativistic formalism for the deuteron structure function is given in the conventional nuclear model. The nucleon density distribution function is obtained by combining the Blankenbecler-Cook vertex factor with the Buck-Gross deuteron wave function. A new procedure is developed to extract the neutron structure function from empirical data on proton and deuteron targets. The results are used to evaluate the deuteron EMC effects in the conventional nuclear model.     

Quark Model for Nuclear Force

Relativistically the corrected transition potential of quark to quark-quark-antiquark is derived. With the input of the quark wave function and the quark-gluon coupling constant determined in a chird quark soliton model, this transition potential is used to obtain the deuteron binding energy in the resonating group method.     

The three-nucleon problems with weak NN interaction

We consider the three-nucleon system in which each two-nucleon pair interacts both strongly and weakly. The strong part is assumed to be separable but an addition of small non-separable term is possible. The weak two-nucleon interaction (which is absolutely non-separable) is assumed to be given in terms of its partial wave components in momentum space. These elements have been calculated by Lassey and McKellar starting from recent models of non-relativistic (strangeness conserving non-leotonic) NN weak interaction. An expression for the weak part of the elastic nucleon-deuteron scattering amplitude is derived within the framework of two potential scattering theory. The weak three-body driving terms are explicitly evaluated. They reflect weak form factors responsible for the weak dissociation of two nucleon isobars (including parity impurity of the deuteron wave function) as well as weak NN scattering. The expressions appearing below are numerically tractable and can be used to elaborate on previous calculations.     

Interaction of relativistic deuterons with nucleons

The processes of the interaction of fast deuterons with nucleonsdN → pX, when the proton is scattered at a large angle inN ? N c.m.s. are analysed. There the wave function of a relativistic deuteron in dynamics of the light cone is used. It is shown that, as in the processes of the deuteron fragmentation type, it is necessary to take into account, the graphs of rescattering and absorption of theπ-meson by a deuteron nucleon, as well as a non-nucleon, quark, degree of freedom in the deuteron. The comparison of the theoretical calculations with the experimental data is performed.     

The Reid93 Potential Triton in the Unitary Pole Approximation

The Reid93 potential provides a representation of the nucleon–nucleon (NN) scattering data that rivals that of a partial wave analysis. We present here a unitary pole approximation (UPA) for this contemporary NN potential that provides a rank one separable potential for which the wave function of the deuteron (³S₁-³D₁) and singlet anti-bound (¹S₀) state are exactly those of the original potential. Our motivation is to use this UPA potential to investigate the sensitivity of the electric dipole moment for the deuteron and ³H and ³He to the ground state nuclear wave function. We compare the Reid93 results with those for the original Reid (Reid68) potential to illustrate the accuracy of the bound state properties.     

On the validity of dwba for deuteron stripping: (I). The Mitra three-body model

Previous work showing that there exists an exact formulation of the DWBA for stripping in the S-wave, separable potential, three-body model of Mitra is discussed and extended. The one-body equation obeyed by the c.m. wave function used in the reformulated DWBA is derived and compared with the equation obeyed by the wave function used in the standard formulation of DWBA, viz., the deuteron elastic scattering wave function. Results obtained by other workers on application of three-body methods to direct reactions are discussed in light of the fact that an exact DWBA exists for the separable potential model.