Eur. Phys. J. C (2006) 48: 427-440
https://doi.org/10.1140/epjc/s10052-006-0033-5

Theoretical Physics

T-odd correlations in radiative K⁺ _ℓ3 decays and chiral perturbation theory

¹ Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, Nußallee 14–16, 53115, Bonn, Germany
² Institut für Kernphysik (Theorie), Forschungszentrum Jülich, 52425, Jülich, Germany

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

Received: 14 July 2006
Revised: 8 August 2006
Published online: 27 October 2006

Abstract

The charged kaon decay channel K⁺ _ℓ3γ allows for studies of direct CP violation, possibly due to non-standard mechanisms, with the help of T-odd correlation variables. In order to be able to extract a CP-violating signal from experiment, it is necessary to understand all possible standard model phases that also produce T-odd asymmetries. We complement earlier studies by considering strong interaction phases in hadronic structure functions that appear at higher orders in chiral perturbation theory, and we compare our findings to other potential sources of asymmetries.