Charmonium decays: J/psi --> e+e- and eta_c --> gamma gamma
High Energy Physics - Phenomenology
2009-11-07 v1
Abstract
We compute the O(alpha_s^2) correction to the decay rate eta_c --> gamma gamma and discuss its implications for precision quarkonium physics. We study the suitability of the ratio Gamma(J/psi --> e+e-)/Gamma(eta_c --> gamma gamma), in which the non-perturbative or soft effects cancel at O(alpha_s^{0,1}), for extracting fundamental parameters of QCD at low energies. We show that the QCD-based theory of charmonia is not capable of predicting this ratio with any degree of confidence.
Cite
@article{arxiv.hep-ph/0109054,
title = {Charmonium decays: J/psi --> e+e- and eta_c --> gamma gamma},
author = {Andrzej Czarnecki and Kirill Melnikov},
journal= {arXiv preprint arXiv:hep-ph/0109054},
year = {2009}
}
Comments
6 pages