Ratio of Axial-Vector to Vector Contributions inK→lνγDecay

Abstract

Sum rules are obtained by using the dispersion technique of Fubini in the radiative weak decay $K\to l\nu \gamma$. The relevant ratio of the axial-vector to vector contributions is then predicted by saturating these sum rules with a few low-lying resonance states, and its relationship with the question of subtraction in the dispersion relation of certain amplitudes in $\mathrm{K}\to l\nu \gamma$ is also discussed.