https://doi.org/10.1140/epjc/s10052-014-2748-z
Regular Article - Theoretical Physics
Approximating chiral 
amplitudes
1
Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 , Vienna, Austria
2
Institut für Kernphysik, Johannes Gutenberg-Universität, 55099 , Mainz, Germany
* e-mail: Gerhard.Ecker@univie.ac.at
Received:
12
November
2013
Accepted:
16
January
2014
Published online:
20
February
2014
We construct large-
motivated approximate chiral amplitudes of next-to-next-to-leading order. The amplitudes are independent of the renormalisation scale. Fitting lattice data with those amplitudes allows for the extraction of chiral coupling constants with the correct scale dependence. The differences between approximate and full amplitudes are required to be at most of the order of N
LO contributions numerically. Applying the approximate expressions to recent lattice data for meson decay constants, we determine several chiral couplings with good precision. In particular, we obtain a value for 
, the meson decay constant in the chiral limit, that is more precise than all presently available determinations.
© The Author(s), 2014
