K -> Pi iota sup + iota sup - Decays in the Effective Chiral Lagrangian of the Standard Model

摘要

The decay amplitudes of K -> pi iota/sup +/iota sup - transitions (iota = e or mu ) are calculated in chiral perturbation theory to lowest non-trivial order. This includes one-loop contributions as well as contributions from all possible tree level counterterms to the corresponding order in momenta and meson masses. Only one combination of counterterm coupling constants appearing in the decay amplitudes remains unknown. Two possible solutions for this constant are found from a comparison with the experimentally known K sup + -> pi sup + e sup + e sup - decay rate. Predictions are then obtained for the rates of K sup + -> pi sup + mu sup + mu sup - , K/sub S//sup o/ -> pi /sup o/e sup + e sup - and K/sub S//sup o/ -> pi /sup o/ mu sup + mu sup - decays as well as for the corresponding spectra in the invariant mass of the lepton pair. The CP-violating transition K/sub L//sup o/ -> pi /sup o/' gamma ' -> pi /sup o/iota/sup +/iota sup - is also discussed. (ERA citation 12:029581)