Hard pion chiral perturbation theory for image and image formfactors Original Research Article

We use one-loop Heavy Meson Chiral Perturbation Theory (HMChPT) as well as a relativistic formulation to calculate the chiral logarithms image contributing to the formfactors of the semileptonic image decays at momentum transfer image away from image. We give arguments why this chiral behaviour is reliable even in the energy regime with hard or fast pions. These results can be used to extrapolate the formfactors calculated on the lattice to lower light meson masses.