Shoji Sawada

Stabilization of skyrmions via ϱ-mesons

Abstract It is shown that a skyrion can be stabilized by introducing ϱ-mesons into the chiral SU(2) L × SU(2) R lagrangian without higher-derivative terms like the Skyrme term. The ϱ-mesons are considered as dynamical gauge bosons associated with a hidden local symmetry of the non-linear sigma model. The lagrangian reduces to the Skyrme model in a limit of parameters. The Skyrmion mass M is found to be M = 1058 MeV when the parameters are fixed so as to satisfy the KSRF relation. It is also shown that a solition solution in a model with Ω-meson coupled with the baryonic current is a saddle-point solution.

One Boson Exchange Model in Proton-Proton Scattering An Approach to the Strong Interaction

A phenomenological model for strong reactions is proposed. In the model it is assumed that the resonance states can be treated as elementary particles as the meson( e (as Fe/sup 59 ) and nucleon and the physical processes can be described by the sum of the lowest order matrix elements. As an application of the model the proton-proton scattering below st run. Concent 300 Mev is studied. It is shown that the present model can successfully explain the experimental phase shifts if the meson( e (as Fe/sup 59 ), scalar boson, and vector boson dominantly contribute to the nuclear force at this energy region. (auth)

Mass Levels of Baryons and Mesons

The relation between the observed mass levels of baryons and mesons is investigated as well as the resonance levelsin plon-nucleon and kaon-nucleon reactions and the various configurations of particle states derived from IkedaOgawa-Ohnukis symmetry theory which is based on Sakata-s composite particle model. It is found that there is a close correspondence between the theoretical levels and the experimental data. (auth)

The study of polarizations of secondary muons in K-Meson decay processes

SummaryTo get the knowledge of weak interactions acting in the K-meson decay processes having the muons in their decay products, the authors have investigated the polarization of the emitted muons in these processes, taking the view-point that the weak Fermi interaction is participating for the decay processes and the neutrino associated is of two components. For the determination of the type of weak interaction in Kμ3-meson it is useful to analyse the longitudinal polarization of muons. Although our main interest is in the type determination of weak interactions, we also examine the spin of the K-meson and our analysis shows that the polarization of muons is in general not complete for spin 1 Kμ2-mesons in contrast with spin 0 Kμ2-mesons.RiassuntoAllo scopo di rilevare le interazioni deboli agenti nei processi di decadimento dei mesoni K fra i cui prodotti di decadimento figurano muoni, gli autori hanno esaminato la polarizzazione dei muoni emessi in questi processi partendo dal punto di vista che l’interazione debole di Fermi sia partecipe dei detti processi e il neutrino associato sia a due componenti. Per la determinazione del tipo dell’interazione debole nei mesoni Kμ3 è utile analizzare la polarizzazione longitudinale dei muoni. Per quanto lo scopo principale fosse quello di determinare il tipo delle interazioni deboli, abbiamo esaminato anche lo spin del mesone K e la nostra analisi mostra che la polarizzazione dei muoni è generalmente iucompieta per i mesoni Kμ2 di spin.l in contrasto coi mesoni Kμ2 di spin 0.

Some features of the electron energy spectrum in the Ke3 decay process

It is shown that there exist some characteristic features in the theoretical energy spectrum of the electrons in K/sub e3/ decay, and the experimental analysis of these simple features seems to be easier than the investigation for the correlation with the pion energy. The electron-pion energy correlation function is given. The ratio of high-energy secondary electrons to lowenergy electrons is investigated. (W.D.M.)

Nuclear Force and OBEC-Model

Characteristics of the nuclear force responsible for the proton-proton scattering below 300 MeV are studied on the basis of the one boson exchange contribution model (OBECmodel). The partial tninsition amplitudes given by the model are so decomposed into five parts that each closely corresponds to central force, tensor force, etc., in the usual potential approach. The differences between OBEC-model and the one boson exchange potential model (OBEP-model) are discussed by making use of these decomposed amplitudes. An analysis of the LS force and quadratic LS force from the OBEC-model suggests a possibility that the hard core introduced in conventional potential is unnecessary for all states . except the singlet S-state.

All-Angle Features of Urbaryon Rearrangement Amplitudes and Two-Step Structure of Constructive Forces

An urbaryon picture having the two-step structure of the constructive forces is proposed. The very strong constructive force of the first kind works among the urbaryons q with large mass and charm charge. By the effect of urbaryon pairs qij in the non-charm state, the urbaryons behave as clusters Q whose effective masses are very light. The rather weak constructive force of the second kind distinguishes hadron states QQ, QQQ from exotic ones QQQQ, QQQQQ, etc., and plays an essential role in hadronic reactions. In the process with a large mome~tum transfer, the urbaryons Q are rearranged as if they were independent free particles. On the basis of this picture, it is shown that the factorizability of urbaryon rearrangement amplitude can be realized.

Learning from Sakata's physics and philosophy

Shoichi Sakata gained invaluable and precious insight for his forty-year-long study from ‘Dialektik der Natur’ (Dialectics of Nature) written by Friedrich Engels.1) The ‘Dialektik der Natur’ had been finally published in 1925 in German and Russian despite its major portion is believed to have been written as early as between early 1870’s and 1880’s, going unpublished for years even after Engels’ death in 1895. Sakata read the book as a Konan High School student in its Japanese edition published in 1929 by a graduate of this school, Tadasi Kato. After graduating from the high school, Sakata was enrolled in the Physics Department at Kyoto University and began learning the revolutionary theories of the 20th century, including the relativity theory and the quantum mechanics, which made him aware of the importance of seeing the nature in dialectic ways. He was also influenced by his reading of Lenin’s ‘Materialism and Empiriocriticism’ whose famous sentence he frequently quoted: “Even the electron is inexhaustible as an atom is.”. Sakata draw his insight from the 1932 discovery of the neutron by James Chadwick for the understanding of the structure of atomic nuclei as the composite system of protons and neutrons. In his dissertation for his bachelor’s degree “On the Theory of Nuclei”, he made practical application of the natural dialectic as a method of analyzing the atomic nuclei.

The F/D Ratios of Spin-Flip Baryon Vertex in 1/Nc Expansion*>

We calculate the F/D ratios of spin 1/2 baryon vertex for both the non-relativistic quark model and the chiral soliton model with arbitrary number of color degrees of freedom Nc and examine the results in terms of the consistency condition approach for the baryon vertices recently developed by Dashen, Jenkins and Manohar from the viewpoint of QCD. We show that the 1/Nc corrections have two different origins, i.e., one is from the baryon states or baryon wave functions and the other from the vertex operators. Although in the limit Nc->oo the F/D tends to 1/3 in all models, the 1/Nc expansion of F/D ratio does not converge for Nc=3 in the chiral soliton model in contrast to the non-relativistic quark model.

POSSIBLE EXISTENCE OF TOPPED HADRONS

We study possibilities of formation of the topped hadrons, the