1999/06/30 by Hai-Yang Cheng
Physics and Astronomy · #hep-ph
published as Chin.J.Phys. 38 (2000) 783 · 19 pages, 1 figure. Errors in the 66 and 88 entries of the constant matrices are corrected
arxiv created 1999/09/02 · arxiv updated 2009/11/30
The K→ππ decay amplitudes are studied within the framework of generalized factorization in which the effective Wilson coefficients are gauge-invariant, renormalization-scale and -scheme independent while factorization is applied to the tree-level hadronic matrix elements. Nonfactorized contributions to the hadronic matrix elements of (V-A)(V-A) four-quark operators, which are needed to account for the suppression of the ΔI=3/2 K→ππ amplitude A2 and the enhancement of the ΔI=1/2 A0 amplitude, are phenomenologically extracted from the measured K+→π+π0 decay and found to be large. The A0/A2 ratio is predicted to lie in the range 15-17 for ms(1 GeV)=(127-150) MeV. Vertex and penguin-type radiative corrections to the matrix elements of four-quark operators and nonfactorized effects due to soft-gluon exchange account for the bulk of the ΔI=1/2 rule. Comparison of the present analysis with the chiral-loop approach is given.