Isovector form factor of the K meson
Krivoruchenko M. I.
A 1D integral representation for the isovector form factor of the ë meson is derived in terms of the π-meson form factor and the amplitude for π ë backscattering. Normalization of the form factor at the origin yields sum rules for the amplitude and makes it possible to find the difference between the s-wave scattering lengths for π ë scattering: Áß0Зαι0/2~0.22μ~\ where μ is the mass of the π meson. The isovector form factor of the ë meson turns out to be numerically close to half the π-meson form factor. This result agrees qualitatively with the vector dominance model.