%0 Conference Paper
%A Durr, Stephan
%T Validity of ChPT - is $M_\pi$=135 MeV small enough ?
%V PoS(LATTICE2014)006
%I Proceedings of Science
%M FZJ-2016-00939
%P 14 p.
%D 2015
%< Proceedings of the 32nd International Symposium on Lattice Field Theory (LATTICE 2014)
%X I discuss the practical convergence of the SU(2) ChPT series in the meson sector, based on 2+1 flavor lattice data by the Wuppertal-Budapest and Budapest-Marseille-Wuppertal collaborations. These studies employ staggered and clover-improved Wilson fermions, respectively. In both cases large box volumes and several lattice spacings are used, and the pion masses reach down to the physical mass point. We conclude that LO and NLO low-energy constants can be determined with controlled systematics, if there is sufficient data between the physical mass point and about 350 MeV pion mass. Exploratory LO+NLO+NNLO fits with a wider range reveal some distress of the chiral series near M_\pi ~ 400 MeV and suggest a complete breakdown beyond M_\pi ~ 500 MeV.
%B 32nd International Symposium on Lattice Field Theory
%C 23 Jun 2014 - 28 Jun 2014, New York (USA)
Y2 23 Jun 2014 - 28 Jun 2014
M2 New York, USA
%F PUB:(DE-HGF)8
%9 Contribution to a conference proceedings
%U https://juser.fz-juelich.de/record/281240