Complete leading order analysis in chiral perturbation theory of the decays K_{L} > γγ and K_{L} > l^{+}l^{}γ
Abstract
The decays K_{L} > γγ and K_{L} > l^{+}l^{}γ are studied at the leading orderp^{6} in chiral perturbation theory. Oneloop contributions stemming from the odd intrinsic parity ΔS = 1 effective Lagrangian of order p^{4} are included and shown to be of possible relevance. They affect the decay K_{L} > γγ adding to the usual pole terms a piece free of counterterm uncertainties. In the case of the K_{L} > l^{+}l^{}γ decays the dependence of the form factor on the dilepton invariant mass requires a counterterm. The form factor may receive a sizeable contribution from chiral logarithms. Including considerations from the K_{L} > π^{+}π^{}γ direct emission amplitude, we obtain two consistent scenarios. In one scenario the long distance contributions from the oneloop terms are important, while in the other they are marginal. In both cases the counterterm is shown to be significant.
 Publication:

Physics Letters B
 Pub Date:
 February 1997
 DOI:
 10.1016/S03702693(97)002463
 arXiv:
 arXiv:hepph/9702387
 Bibcode:
 1997PhLB..398..387G
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 10 pages, one table, two figures. One reference has been added and one typo in reference to Enagonio et al. has been corrected