No abstract available

[en] Typical nonleptonic weak decays of strange and charm mesons are studied from the approach in which dynamical features of hadrons are dealt with in earnest. The amplitudes are always cast into the form M ≅ M_ETC + M_S by using a hard PS-meson extrapolation. M_S, which can then be regarded as the Born term, is described by the sum of pole amplitudes involving the contributions from not only the ordinary {QQ-bar} but also the exotic [QQ][Q-barQ-bar] and (QQ)(Q-barQ-bar) mesons and a glue-ball. In particular, the persistent puzzle of the ratio, Γ(D⁰ → K⁺K^-)/Γ(D⁰ → π⁺π^-) ≅ 2-5, can be solved. Simultaneously, the contribution of the (QQ)(Q-barQ-bar) mesons explains why the violation of the |ΔI| = 1/2 rule is small in the K → ππ decays, while its charm counterpart is violated strongly. (author)

[en] Individual papers are separately abstracted

[en] From a new perspective developed towards the approximate |ΔI| = 1/2 rule in K → ππ decays and the K_L-K_S mass difference in which vector mesons play a crucial role, we argue for the K_L → γγ^* decay that the contribution of the K^* meson does also play a role, in addition to those of the PS mesons. However, the glue-ball contribution through the Penguin is found to be small. (author)

[en] We argue that the asymptotic behavior of the weak matrix elements involving the on-mass-shell ground-state mesons with infinite momenta, which was instrumental in explaining the |ΔI| = 1/2 rule in the K → ππ decays, actually implies the vanishing of the matrix element of the local |ΔS| = 2 quark operator arising from the box diagram, when it is taken between |K⁰| and |K-bar⁰| states. In contrast, the long distance contribution, arising from the ππ intermediate states as well as the poles of the vector and pseudoscalar mesons, may alone reproduce the observed K_L-K_S mass difference, in consistency with the selection rule and the rates of the K → ππ decays, depending on the values of the η-η'- · mixing. (author)

[en] Contrary to the expectation of naive spectator model, D⁰ → φK-bar⁰ decay has recently been observed with appreciable branching ratio. In this paper, it is however pointed out that the sizable rate of D⁰ → φK-bar⁰ decay is, in fact, no surprise in the newly developed algebraic approach to non-leptonic weak interactions and it can be estimated from the well-known rate of K_S → 2π decays. The value of Γ(D⁰ → φK-bar⁰) thus obtained is in good agreement with experiments. The approach uses hard PS-meson extrapolation instead of soft one and deals with long distance physics in earnest, by using the algebraic method developed in the framework of asymptotic flavor symmetry which neverthless maintains a close connection with quark-line diagrams. (author)

[en] Present status of algebraic approach (including the conventional group theoretical method) to new boson resonances in SU(4) is reviewed. The mass formulas, intermultiplet mass relations and the derivation of selection rules for the new resonances are discussed. It is stressed that one does not need to subscribe to the perturbation theoretic point of view towards SU(4) breaking. A possible relation between the SU(3) and SU(4) world is demonstrated. Some crude discussion is given to the new possible P-wave states in the 3.4 to 3.5 GeV region and the problems associated with the X

[en] Quasi two-body decays of D⁰-meson are studied from an algebraic approach, using a hard meson extrapolation. In this innovation of old current algebra with new perspective, a reasonable unified description of K sub(S) → 2π and D⁰ → K-barπ decays has been obtained previously, keeping only the contribution of ground state mesons to the now surviving surface term. In this paper, it is shown that quasi two-body decays can also be accomodated reasonably well in the same scheme. A distinctive feature of our result is that GAMMA(D⁰ → phi K-bar⁰) is sizable, while D⁰ → rho⁰K-bar⁰ is relatively suppressed. (author)

[en] A systematic study of the 1^-- → 0^-+ + γ and 0^-+ → 1^-- + γ is presented in the framework of asymptotic SU(4) and SU(4) charge-current commutation relation. A special emphasis is placed on the phi/sub c/ → eta/sub c/γ decay. Also the decays of phi/sub c/ → πγ, etaγ and eta'γ, and eta/sub c/ → rhoγ, phiγ and ωγ, which emerge through the breaking of the Okubo-Iizuka-Zweig selection rule, are discussed

No abstract available