Second-Order Weak Processes and Weak-Interaction Cutoff

The problem of the weak-interaction cutoff Λ has been studied with the universal current-current theory (UFI) and the intermediate-vector-boson (IVB) model, using the Bjorken technique to treat the high-energy behavior and the "hard meson" technique of Weinberg and Schnitzer. With these methods, the most divergent contributions to the second-order weak decay KL⁰→μμ and KL⁰-KS⁰ mass difference Δm are essentially independent of strong interaction. From KL⁰→μμ decay, Λ35-100 BeV, and from Δm, Λ3-4 BeV. With this latter value of Λ, the predicted rate of KL⁰→μμ is reduced to a value obtained by B\'eg treating this process as first-order in weak and second-order in electromagnetic interaction. The B\'eg calculation is redone with the algebra of currents, and the soft-kaon contribution to KL⁰→μμ is calculated with both the UFI and IVB models. A possible origin of the low value of Λ deduced from Δm is discussed.