Interrelation among effective weak Yukawa interactions and various types of two-body weak interactions is discussed, and the refinement of the pole approximation is given. For this purpose, relations among three assumptions are investigated. Assumption I proposed by Fujii and Terazawa leads to the soft-meson theorem, owing to which one can relate the strong scattering amplitudes (the strong vertices) to the weak vertices (the effective two-dody weak interactions), and octet-spurion formalism and tadpole model are derived. The decupletbaryon-pole contributions to the hyperon decays are estimated in accordance with Assumption I and are shown to be relatively small.Relation of the effective two-body transition defined by using appropriate neutral currents ia< 7 ) and j 5 a< 7 > (Assumption II) to the scalar-and psuedoscalar densities is discussed. It is shown first that the effective two-body transition derived from Assumption II can be regarded as approximately proportional to the scalar-and pseudoscalar densities with appropriate SU (3).transformation properties, and secondly that, using the F-type vector current, one can obtain favourable values for the ratios of coupling constants of the effective two-body weak transition.In the framework of the pole approximation, when one combines Assumption I (or Assumption HI--approximate Goldberger-Treiman relation) with Assumption II one can obtain the relations derived from Assumption III (or I). As a result, it is shown that the relation Av(n) """'d·A 8 (n) """'e·AB (n) holds for any n (decay mode) and ~ (F/D-ratio of strong meson-baryon ps(ps) interaction) ""'"'(0.5""--'0.6), where Av(n), A 8 (n) and AB(n) mean the S-wave hyperon decay amplitudes due to the K*-, K-and baryon-poles, respectively, and d and e are constants. Numerical values of d and e and the scalar (pseudoscalar) spurion coupling, ' 17 > 1n"'~7;30 Mev and r/C~12 Mev or 50 Mev. 16 ),l?)We adopted tc 1° (the sixth member of scalar octet) and I<:} (the seventh men1ber *> Note that K 0 = (K 2°-iK 1°) lv-' /v-z·. K1° and K1° are the CP-even com-ponents· **> Judging from the note added in proof of the paper by Riazuddin and Mahanthappa,H iv) a similar idea also has been proposed by them for H)j2 . by guest on April 13, 2015

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On the basis of the lightlike chiral structure of hadrons, we investigate the S-and P-wave nonleptonic decays of hyperons. Assuming that (i) the 1/2c octet baryons transform as (6, 3) under the chiral SU, (3) (?)SU, (3) and (ii) the weak Hamiltonian transforms as octet under either the left-handed or the right-handed SU, (3), we show that the equal x+ -commutator terms satisfy the Lil=l/2 rules and the L-S relation for the S-wave decays, and the L1I=li2 rule for the P-wave I -decays. @SU, (3) . 91 Encouraged by its success in understanding the hadron spectrum and the pionic decays of hadron resonances, we investigate the nonleptonic hyperon decays in this scheme.In this paper we sho\v that this scheme, under some assumptions, can gi,-e not only a unified description of the Sand P-wave decays but also some further insight into the difficulty of the P-wave decays. Our investigation in this paper is restricted to the equal x~-commutator in the light-front reduction formula. 101 Relying on Ida's analysis, we take the 1 /2+ octet baryon with helici ty + 1 to be dominantly in the representation (6, 3) of SU1 (3) @SU1 (3). In contrast to the usual octet dominance hypothesis of the weak Hamiltonian, \Ye assume that it transforms as octet under either the left-handed or the right-handed SU1 (3). Our at Florida International University on July 11, 2015 http://ptp.oxfordjournals.org/ Downloaded from A.sszmzjJtion (II): The weak Hamiltonian transforms as octet under either the left-handed or the right-handed sul (3). On this assumption the vveak Hamiltonian becomes Hw =aJI(8, I) +a2H(I, 8) +a3 II { (8, 8); 8,} +a,H{ (8, 8); 27}. (2) \Ve are led to this Hamiltonian by the following considerations. Starting from the quarks, which transforms as (3, I)+ (L 3) 12 J under the chiral SU1 (3) '>?;;SU1 (3), we construct the usual V-L'i current. From the symmetrical product of two octet currents of this type ~with relevant SU(3) indices, we pick up those terms which are allowed from the Assumption (II). Thus we arrive at Eq. (2). With the help of the generalized parity transformation.w it at Florida