Pion Physics at Low Energy and High Accuracy
High Energy Physics - Phenomenology
2009-11-07 v1
Abstract
The role of the quark condensate for the low energy structure of QCD is discussed in some detail. In particular, the dependence of M_pi on m_u and m_d and the low energy theorems for the pi-pi scattering amplitude are reviewed. The new data on Ke4 decay beautifully confirm the standard picture, according to which the quark condensate is the leading order parameter of the spontaneously broken chiral symmetry.
Cite
@article{arxiv.hep-ph/0107332,
title = {Pion Physics at Low Energy and High Accuracy},
author = {H. Leutwyler},
journal= {arXiv preprint arXiv:hep-ph/0107332},
year = {2009}
}
Comments
Talk given at the Workshop QCD@Work, Martina Franca, June 2001