Two-baryon Systems Research Articles

Skyrmions for two-baryon systems

We survey the application of skyrmions to nucleon-nucleon forces, starting from general background material on the search for appropriate degrees of freedom (nucleonic, mesic, quark,…) for few-nucleon systems. We stress that skyrmions may offer a link in the chain from quantum chromodynamics (QCD) as a theory of strong interactions on the one hand to nuclear structure on the other. We briefly consider possible extensions of the skyrmion approach to the strange sector, where one may treat, among other systems, NΛ, NΣ and ΛΛ forces.

Instanton-induced quark-quark interactions in two-baryon systems.

We study effects of instanton-induced quark-quark interactions in baryon spectroscopy and in the baryon-baryon interaction. The quark-cluster model is applied to calculating baryon-baryon interactions. Results are compared with those of the one-gluon-exchange interaction. We propose a new phenomenological model which contains both the instanton-induced interaction and the one-gluon-exchange potential.

Constituent quark model with strangeness

One- and two- baryon systems with strangeness are discussed within the framework of the quark cluster model. The effects of coupling with mesons on baryon spectra and baryon-baryon interaction are studied. Both the conventional two-body confinement and the flip-flop confinement are tried for two-baryon systems. The possibility of stable H-particle is also examined.

Deformation Effect on the Skyrmion-(Anti-)Skyrmion Interaction Potential in the -Stabilized Skyrme Model

The Skyrme modeF) attracts interests both from the viewpoint of the effective lagrangian of the QeD and from the phenomenological aspect. A lot of efforts have been devoted to investigating the properties of oneand two-baryon systems by the original and generalized Skyrme models.)-9) In the course of the studies, it has been clarified) that the co-meson coupling term plays an important role in the model, and that the stabilization of the Skyrmion may depend strongly on the term. The static properties of the nucleon are known to be cosiderably improved by the model with the co-meson term, and the characteristic features of the nucleon-nucleon (NN) potential can also be fairly well reproduced by the model. One notes that the correct G-parity structure of the central potential is obtained by including the co-meson term. No improvement is, however, obtained for the medium-range attraction of the central potential; the resulting potential does not show any attraction necessary for the nuclear binding. Recently, it was shown that in the original Skyrme model the central potential is reduced by the amount of about 10 to 20% by taking into account a deformation effect of the Skyrmion.) The small amount of the reduction comes from the fact that the Skyrme term resists strongly such a deformation. On the other hand, Hajduk and Schwesinger ) showed that the co-meson term IS not influenced by the deformation of the Skyrmion. Then, it is very interesting to study to what extent the central potential in the Skyrmion-Skyrmion (SS) interaction is affected by the deformation of the Skyrmion in such a model, since the Skyrmion seems to be soft for the deformation. In this paper, we investigate such an effect on the central potential for the model of Adkins and N appi,4) where the Skyrmion is stabili~ed by the co-meson term instead of the so-called Skyrme term. There is so far no explicit calculation of the deformation effect on the Skyrmion-Skyrmion potential projected onto the central potential. The lagrangian adopted here is

Hyperon-nucleon and hyperon-hyperon interaction in a quark model

The non-relativistic quark cluster model is employed to describe the two-baryon systems including hyperons such as Λ, Σ and Ξ. Qualitative discussions about the role of the Pauli principle for quarks and the color magnetic interaction in the baryon-baryon scattering are given. Results of the resonating group method (RGM) calculation show a repulsive interaction at short distances in most of the two-baryon systems with strangeness S = −1 and −2. There appears, however, a sharp resonance in the 1S 0ΛΛ scattering at E = 26.3 MeV, which may correspond to the di-hyperon state.

Hadron-hadron interaction in a string-flip model of quark confinement. II. Nucleon-nucleon interaction.

The string-flip model of quark confinement is extended and applied to two-baryon systems with color, spin, and flavor degrees of freedom. The model avoids a pathological color van der Waals force, unlike a conventional two-body quark-confining potential model. Resonating-group-method calculations of the N-N phase shifts are presented for several different color-dependent potentials. A realistic model with a short-range interquark potential and an effective meson-exchange interaction is proposed and found to reproduce $^{1}\mathrm{S}_{0}$ N-N scattering data very well.