QCD isospin breaking ChPT low-energy constants from the instanton vacuum
High Energy Physics - Phenomenology
2010-04-14 v2
Abstract
In the framework of the instanton vacuum model we evaluate the Chiral Perturbation Theory (ChPT) low-energy constants h_3,l_7. We found that in the instanton vacuum model the constant l_7 is very sensitive to the shape of the instanton and the instanton vacuum parameters. We evaluated the constant l_7 for two different zero-mode profiles and as a function of the average instanton size \rho and inter-instanton distance R. Our result agrees with an old "order of magnitude" estimate of this constant from [1]. The obtained value of l_7 implies that the pure QCD contribution to the pion mass difference is small, ~1% of the observed experimental value.
Keywords
Cite
@article{arxiv.1002.0283,
title = {QCD isospin breaking ChPT low-energy constants from the instanton vacuum},
author = {K. Goeke and M. Musakhanov and M. Siddikov},
journal= {arXiv preprint arXiv:1002.0283},
year = {2010}
}
Comments
17 pages, 4 Figures. In the version 2 several unclear statements were clarified