Are "Penguins" Black-and-White?
High Energy Physics - Phenomenology
2009-10-28 v1
Abstract
Contributions of low energy "eye" and "figure-eight" quark diagrams to the weak transitions are studied in a hadron- level phenomenological approach. It is shown that these contributions may be estimated by considering meson-cloud effects. If all intermediate mesons under consideration are degenerate only the "eye" (low-energy penguin) diagram is nonvanishing. When allowance is made for smaller mass of pseudoscalar mesons, the contribution of "figure-eight" diagrams turns out to enhance the (suppress the ) amplitudes naturally. The overall long-distance-induced enhancement of the ratio of the amplitudes over the amplitudes is estimated at around 4-8.
Cite
@article{arxiv.hep-ph/9504227,
title = {Are "Penguins" Black-and-White?},
author = {P. Zenczykowski},
journal= {arXiv preprint arXiv:hep-ph/9504227},
year = {2009}
}
Comments
23 pages, LaTeX