Shin-ya Furui

Boson levels and composite model in U4 symmetry

SummaryFollowing the extended Sakata model where the four fundamental r-baryons are introduced, we assume the approximateU4 symmetry and investigate the mass splitting of bosons which comes from the mass differences of ur-baryons in our model. Several relations among masses of both known and unknown bosons are obtained.RiassuntoSeguendo il modello di Sakata esteso nel quale sono introdotti quattro ur-barioni fondamentali, supponiamo la simmetriaU4 approssimata e studiamo la separazione di massa dei bosoni che deriva dalle differenze di massa degli ur-barioni del nostro modello. Otteniamo pareccbie relazioni fra le masse dei bosoni sia noti che sconosciuti.

Gauge interaction of baryons in hidden local symmetry

SummaryThe hidden local symmetry of the non-linear sigma model is extended to include baryons. In two papers (M. Bando, T. Kugo and Y. Yamawaki:Phys. Rep.,164, 217 (1988);Prog. Theor. Phys.,73, 1541 (1985)), the low-energy theorems for mesons were successfully reproduced. It seems important to investigate whether some kind of the low-energy theorems for baryons holds in the same framework. Indeed, theS-wave pion-nucleon scattering lengths, the conserved vector currents (CVC) of β-decays of baryons and Sakurais scenario of the electromagnetic interactions of hadrons are all reproduced. Our interaction Lagrangians are stable under the small variation of each vertex. Thus, they deserve the effective one.

Chiral symmetry breaking in hidden local symmetry

SummaryChiral breaking for baryon and meson interaction is formulated in the framework of the hidden local symmetric theory of the non-linear sigma model on the manifoldU(3)L×U(3)R/U(3)V. The chiral symmetry-breaking term transforms as (3,3*) underU(3)L×U(3)R at the first order. Several low-energy theorems are derived for the electromagnetic interaction of baryon. The symmetry-breaking term preservesSU(2)×U(1) symmetry; we have confirmed that the Sakurai formula of the electromagnetic interaction of vector meson holds and directly shown that the photon mass vanishes. The fundamental gauge coupling constantg and the mixing angle θ of vector meson are fixed by independent phenomena of vector meson masses and eē decay of vector meson. Using these values ofg and θ, we extend our analysis to the nucleon form factor and indicate a breaking of the OZI rule and a sizable contents of s-quark pair in the nucleon.

Nucleon electromagnetic form factors in hidden local symmetry theory

SummaryIn previous papers (Nuovo Cimento A,108 (1995) 241, 1051), the hidden local symmetry of the chiral theory based on the non-linear sigma-model on the manifoldU(3)L×U(3)R/U(3)V was extended to the baryon interaction and shown to reproduce well the low-energy theorems. Introducing anSU(3) breaking in the theory, the mass formula and the Sakurai formula of the electromagnetic interaction of vector mesons are obtained consistently. In this paper, by introducing the effective tensor interactions of orderO(p2), the magnetic form factor of the nucleon is analysed as well as the electric form factor, partly done in the previous papers, and a breaking of the OZI rule and a sizeable content of s-quark pair in both the electric and magnetic form factors of the nucleon are indicated again.