epsilon'/epsilon in the 1/N_c Expansion
Abstract
We present a new analysis of the ratio epsilon'/epsilon which measures the direct CP violation in K\to\pi\pi decays. We use the 1/N_c expansion within the framework of the effective chiral lagrangian for pseudoscalar mesons. From general counting arguments we show that the matrix element of the operator Q_6 is not protected from possible large 1/N_c corrections beyond its large-N_c or VSA value. Calculating the 1/N_c corrections, we explicitly find that they are large and positive. Our result indicates that a \Delta I=1/2 enhancement is operative for Q_6 similar to the one of Q_1 and Q_2 which dominate the CP conserving amplitude. This enhances epsilon'/epsilon and can bring the standard model prediction close to the measured value for central values of the parameters.
Keywords
Cite
@article{arxiv.hep-ph/9908232,
title = {epsilon'/epsilon in the 1/N_c Expansion},
author = {T. Hambye and P. H. Soldan},
journal= {arXiv preprint arXiv:hep-ph/9908232},
year = {2007}
}
Comments
9 pages, LaTeX, talk presented by T. Hambye at the 1999 Chicago Conference on Kaon Physics (KAON 99), Chicago, IL, 21-26 Jun 1999