TY - CONF AU - Durr, Stephan TI - Validity of ChPT - is $M_\pi$=135 MeV small enough ? VL - PoS(LATTICE2014)006 PB - Proceedings of Science M1 - FZJ-2016-00939 SP - 14 p. PY - 2015 AB - 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. T2 - 32nd International Symposium on Lattice Field Theory CY - 23 Jun 2014 - 28 Jun 2014, New York (USA) Y2 - 23 Jun 2014 - 28 Jun 2014 M2 - New York, USA LB - PUB:(DE-HGF)8 UR - https://juser.fz-juelich.de/record/281240 ER -