https://doi.org/10.1140/epjc/s10052-016-4542-6
Regular Article - Theoretical Physics
Convergence properties of 
decays in chiral perturbation theory
Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, 18000, Prague, Czech Republic
* e-mail: kolesar@ipnp.troja.mff.cuni.cz
Received:
9
August
2016
Accepted:
28
November
2016
Published online:
21
January
2017
The convergence of the decay widths and some of the Dalitz plot parameters of the decay seems problematic in low energy QCD. In the framework of resummed chiral perturbation theory, we explore the question of compatibility of experimental data with a reasonable convergence of a carefully defined chiral series. By treating the uncertainties in the higher orders statistically, we numerically generate a large set of theoretical predictions, which are then confronted with experimental information. In the case of the decay widths, the experimental values can be reconstructed for a reasonable range of the free parameters and thus no tension is observed, in spite of what some of the traditional calculations suggest. The Dalitz plot parameters a and d can be described very well too. When the parameters b and 
are concerned, we find a mild tension for the whole range of the free parameters, at less than 2
C.L. This can be interpreted in two ways – either some of the higher order corrections are indeed unexpectedly large or there is a specific configuration of the remainders, which is, however, not completely improbable.
© The Author(s), 2017
