Chiral perturbation theory for nonleptonic weak interactions

Abstract

The chiral lagrangian for nonleptonic weak interactions of mesons is computed up to one loop order, including all counterterms of order p 4 in the low energy expansion. Applications to CP-conserving K → 2 π, 3 π decays reveal that corrections to the lowest order results are large, e.g. 30–100 % depending on the amplitude considered. This may have consequence on calculational techniques which use chiral lagrangians in lowest order. Neglecting terms of order M 2 π / M 2 k , we derive three parameter free sum rules which correct the usual soft pion theorems.