QUARK OFF-SHELL EFFECTS IN FLAVOUR-CHANGING DECAYS

Abstract

We discuss some flavour-changing effective Lagrangians, obtained from scales above 1 GeV, which vanish on the quark mass shell. Although the effects of such effective Lagrangians are zero in the limit of vanishing bound-state interactions, we have shown that they have a significant impact on the processes $K\to \gamma \gamma$ and $B_s\to \gamma \gamma$.

Comments: 10 pages (latex), uses (appended) macros required by the World Scientific publisher, 3 figures not included, talk given by J.O. Eeg at the 7th Adriatic Meeting on Particle Physics, Brijuni, Croatia (September 1994)