K. Nakayama

Effective quasiparticle G-matrix interaction

Abstract A derivation of the operator structure of the Brueckner G -matrix is presented. This method is used to extract¦an effective interaction based on a G -matrix in nuclear matter derived from a one-boson-exchange potential. Effects of Pauli blocking and short-range correlations have been analyzed, showing that they are essentially restricted to 1 S 0 and 3 S 1 - 3 D 1 states. The reason why the tensor force is not significantly affected by correlations is also discussed. A momentum transfer and density-dependent interaction has been constructed which may be used as a basic ingredient of the full particle-hole interaction to describe the low-lying excited states of nuclei. For further convenience, this interaction has been parametrized in terms of Yukawa-type expressions, which reproduce the exact values within 0.2% in the range of 0–2 fm −1 of momentum transfer. Based on the analysis of an analytical G -matrix, a simple functional form for the density dependence is suggested which provides an excellent fit (within 1%) in the range of the density of 0.35 ϱ 0 ⩽ ϱ ⩽ ϱ 0 . G -matrix interactions based on several phase-shift-equivalent NN potentials are considered in the Landau limit and they show a considerable sensitivity to these potentials. The results can be understood within the context of a very simple model and this provides a better understanding of different channels of the G -matrix interaction, especially those which are relatively poorly understood.

Quasiparticle relativistic G-matrix interaction

Abstract A quasiparticle G -matrix interaction has been constructed from a three-dimensional integral equation which is a relativistic generalization of the conventional non-relativistic Bethe-Goldstone equation. Relativistic dynamical effects have been discussed by comparing the relativistic and the conventional non-relativistic G -matrices. The Landau theory and, in particular, the quasi-particle current have also been discussed within the present relativistic formulation. As an example of application, the quasiparticle relativistic G -matrix interaction has been used in the RPA calculation which includes 2p-2h processes.

An analysis of the reaction pp --> pp\eta near threshold

It is shown that most of the available data on the

A simple model for short-range correlations in nuclear matter☆

ppto ppeta

On the description of the giant resonances within an RPA formalism with good isospin

reaction, including the invariant mass distributions in the

The reactions pn→dω and pn→dφ and the role of the OZI rule

ppto ppeta

Energy and density dependence of the isovector tensor interaction.

reaction recently measured at COSY, can be understood in terms of the partial-wave amplitudes involving final

Analysis of the reactionpp→ppηnear threshold

pp

The reactions pn -> d omega and pn -> d phi near threshold

S