[en] This issue is the collection of the paper presented at the title meeting. The 13 of the presented papers are indexed individually. (J.P.N.)

[en] We review chiral dynamics for low energy hadron physics. After a brief look at the standard theory for strong and weak interactions, we discuss chiral symmetry and its spontaneous breaking in some detail. Applications of the chiral perturbation theory to the strong interaction physics is the main subject. We also discuss some weak interaction processes. (author)

[en] DIRAC experiment at CERN is aimed at measuring the lifetime of A_ππ atom precisely and deducing the S-wave ππ scattering length within 5% of precision. The experiment has been approved in 1996 and now the data taking is going on. The overview of the experiment is reported here with a stress on the part that the Japanese group is taking care of. Some preliminary results are also presented. (author)

[en] We discuss the chiral unitary model as a powerful tool for the description of hadronic phenomena at low energy. The chiral unitary model is able to describe the meson-meson scattering as well as the meson-baryon scattering except for the delta channel. We discuss a possible connection of this model with the quark model. We then study the scalar-isoscalar channel of the nucleon-nucleon interaction within the chiral unitary model. (author)

[en] The Λ(1405) is a unique candidate for a meson-baryon bound state and for testing a reliability of the χPT. While a large body of low-energy K^-p scattering data is available, the Λ(1405) data set is very limited for more detailed analysis. The present status of the Λ(1405) thus depends heavily on theoretical arguments. In this regard, a planned SPring-8 experiment for the Λ(1405) photoproduction will give a clue on the nature of the Λ(1405) and also test competing model predictions. Some experimental points of view are discussed. (author)

[en] We review the non-leptonic weak decay of hyperons and ΔI=1/2 rule with a special emphasis on the role of chiral symmetry. The soft-pion theorem provides a powerful framework to understand the origin of ΔI=1/2 rule qualitatively. However, quantitative description is still incomplete in any model of the hadrons. Naive chiral perturbation theory cannot explain the parity-conserving and violating amplitudes simultaneously, and convergence of the chiral expansion seems to be worse. We demonstrate how the non-leptonic weak decay amplitudes are sensitive to the quark-pair correlation in the baryons, and show the importance of the strong quark correlation in the spin-0 channel to reproduce the experimental data. We finally remark several related topics. (author)

[en] We discuss the hadron matrix elements of QCD and electroweak penguin operators in K → ππ using nonlinear sigma model with scalar resonances. The scalar mesons are introduced as a nonet representation under flavour SU(3) transformation. The propagators of the scalar resonances have the effect of resuming a certain class of chiral corrections to the matrix elements to all order in chiral perturbation theory. Using these results, the impact on the physical observable in kaon decay, ΔI=1/2 rule and ε'/ε, are discussed. We show the effects of σ meson are of great importance in K → ππ when mass of the σ meson is near to the kaon threshold due to propagator enhancement. However our results show that we are still missing some large amount of contributions to explain both of ΔI=1/2 and ε'/ε consistently. An plausible explanation may be non-factorizable contributions, thus chiral loop corrections to the matrix elements may help us with deep understanding on the decay K → ππ. (author)

[en] This report reviews two recent experimental results on radiative K⁺ decays at BNL-E787. One is the first observation of the decay K⁺ → π⁺γγ, and the other is a new measurement of the K⁺ → π⁺π⁰γ decay. The former provides a testing ground for loop calculations of the Chiral Perturbation Theory at O(p⁴), and the latter tests the chiral anomaly. (author)

[en] DIRAC experiment is under way at CERN-PS with an aim of testing the predictions of the chiral perturbation theory of QCD for the S-wave ππ-scattering length (actually Δ=a₀⁰-a₂⁰, where a_I^L=ππ-scattering length of orbital angular momentum L and isospin I). The target accuracy of the measurement is 5%, which is the accuracy of the theoretical prediction at present. After a brief review for the theoretical and experimental values for the scattering lengths, the experimental method to derive the ππ-scattering length from measurement of the lifetime of π⁺π^--atoms, the estimated ambiguity for the scattering lengths, etc. are described. A few discussions are also given including alternate methods to obtain the scattering lengths from measurement of the decay of π⁺π^--atoms. (author)

[en] The decay spectra and/or branching ratios of the weak semi-leptonic, non-leptonic and rare radiative B meson decays are analyzed, taking into account the confined effects of quarks, by the covariant oscillator quark model (COQM). The effective weak current of B→(D, D^* and the first excited D^**) transitions, J_μ^B→D,D* and J_μ^B→D**, takes the same form as the one obtained by heavy quark effective theory (HQET) in the infinite heavy quark mass limit. The reduced form factor function (Isgur-Wise function) for B→(D, D^*) transitions satisfies the normalization condition at zero-recoil point in HQET. The COQM is also applicable to heavy-to-light transition, such as B→ρ. Overall agreement of the theoretical predictions of the decay widths with the present experimental data suggests the estimation of quark-confined effects by COQM is valid and the covariant framework describing composite qq-bar meson systems in COQM is actually realized in nature. (author)