Eur. Phys. J. C (2007) 50: 557-571
https://doi.org/10.1140/epjc/s10052-007-0215-9

Regular Article - Theoretical Physics

Aspects of radiative K⁺ _e3 decays

¹ Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, Nussallee 14–16, 53115, Bonn, Germany
² School of Physics, University of Edinburgh, King’s Buildings, Mayfield Road, Edinburgh, EH9 3JZ, UK
³ Institut für theoretische Physik, Universität Bern, Sidlerstrasse 5, 3012, Bern, Switzerland

^* e-mail: kubis@itkp.uni-bonn.de

Received: 30 November 2006
Published online: 9 February 2007

Abstract

We re-investigate the radiative charged kaon decay K^±→π⁰e^±ν_eγ [K_e3γ ^±] in chiral perturbation theory, merging the chiral expansion with Low’s theorem. We thoroughly analyze the precision of the predicted branching ratio relative to the non-radiative decay channel. Structure dependent terms and their impact on differential decay distributions are investigated in detail, and the possibility to see effects of the chiral anomaly in this decay channel is emphasized.