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Data indicate that ΔI = 3/2 transitions account for 4.5–4.7% of both CP conserving and CP violating K → 2π decays, as well as CP conserving radiative K → π πγ processes. Observed K → π πγ/ π π branching ratios are shown to scale near α/ π or α/ π. The KL-KS mixing angle ∅ and the semileptonic weak-rate asymmetry δ are reviewed, and theory is shown to be consistent with data. Also, K → 2π ΔI = 1/2 dominance is studied in the context of the chiral constituent quark model, displaying again excellent agreement with data. Finally, indirect and direct kaon CP violation (CPV) are successfully described in the framework of photon-mediated quark-loop graphs. This suggests that kaon CPV can be understood via second-order weak transitions, radiatively corrected. [ABSTRACT FROM AUTHOR]

The quark-level linear σ model (LσM) is employed to compute a variety of electromagnetic and weak observables of light mesons, including pion and kaon form factors and charge radii, charged-pion polarizabilities, semileptonic weak Kℓ3 decays, semileptonic weak radiative pion and kaon form factors, radiative decays of vector mesons, and nonleptonic weak K2π decay. The agreement of all these predicted observables with experiment is striking. In passing, the tight link between the LσM and vector-meson dominance is shown. [Copyright &y& Elsevier]

The quark-level linear σ model (LσM) is revisited, in particular concerning the identification of the f[sub 0](400-1200) (or σ(600)) scalar meson as the chiral partner of the pion. We demonstrate the predictive power of the LσM through the ππ and πN s-wave scattering lengths, as well as several electromagnetic, weak, and strong decays of pseudoscalar and vector mesons. The ease with which the data for these observables are reproduced in the LσM lends credit to the necessity to include the σ as a fundamental q&qmacr; degree of freedom, to be contrasted with approaches like chiral perturbation theory or the confining NJL model of Shakin and Wang. [ABSTRACT FROM AUTHOR]

Presents an obituary for U.S. physicist Leon Blitzer.