Splitting Strong and Electromagnetic Interactions in K(L4) Decays

Abstract

We recently considered $K_{\ell 4}$ decays in the framework of chiral perturbation theory based on the effective Lagrangian including mesons, photons, and leptons. There, we published analytic one-loop-level expressions for form factors $f$ and $g$ corresponding to the mixed process, $K^0\to {\pi }^0{\pi }^{-}{\ell }^{+}{\nu }_{\ell }$. We propose here a possible splitting between strong and electromagnetic parts allowing analytic (and numerical) evaluation of Isospin breaking corrections. The latter are sensitive to the infrared divergence subtraction scheme and are sizeable near the $\pi \pi$ production threshold. Our results should be used for the extraction of the $P$-wave iso-vector $\pi \pi$ phase shift from the outgoing data of the currently running KTeV experiment at FNAL.

47 pages, LaTeX, 6 postscript figures

References in corpus (2)

• Big Bang Nucleosynthesis (in "The Review of Particle Properties" 2004)
• Isospin Breaking in $K_{\ell 4}$ Decays of the Neutral Kaon

Cited by in corpus (7)

• Kaon Decays in the Standard Model
• Isospin breaking in Kl4 decays
• Instantons, diquarks and non-leptonic weak decays of hyperons
• Determination of SU(2) Chiral Perturbation Theory low energy constants from a precise description of pion-pion scattering threshold parameters
• The ${\pi }^0-\eta -{\eta }^{\prime }$ mixing in a generalized multi-quark interaction scheme
• Isospin-Breaking quark condensates in Chiral Perturbation Theory
• Size of Isospin Breaking in Charged K(L4) Decay