Eur. Phys. J. C (2008) 53: 549-557
https://doi.org/10.1140/epjc/s10052-007-0493-2

Regular Article - Theoretical Physics

Electromagnetic low-energy constants in χPT

¹ Departament de Física Teòrica, IFIC, Universitat de València – CSIC, Apt. Correus 22085, 46071, València, Spain
² Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980, Dubna (Moscow region), Russia
³ Institute for Theoretical Physics, University of Bern, Sidlerstr. 5, 3012, Bern, Switzerland

^* e-mail: haefeli@ific.uv.es

Received: 7 November 2007
Published online: 22 December 2007

Abstract

We investigate three-flavour chiral perturbation theory including virtual photons in the limit in which the strange quark mass is much larger than the external momenta and the up and down quark masses, and where the external fields are those of two-flavour chiral perturbation theory. In particular, we work out the strange quark mass dependence of the electromagnetic two-flavour low-energy constants C and k_i. We expect that these relations will be useful for a more precise determination of the electromagnetic low-energy constants.