Nucleon electromagnetic form factors with non-local chiral effective Lagrangian

The relativistic version of finite-range-regularisation is proposed. The covariant regulator is generated from the nonlocal Lagrangian. This nonlocal interaction is gauge invariant and is applied to study the nucleon electromagnetic form factors at momentum transfer up to 2 GeV${}^2$. Both octet and decuplet intermediate states are included in the one loop calculation. Using a dipole regulator with $\mathrm{\Lambda }$ around 0.85 GeV, the obtained form factors, electromagnetic radii as well as the ratios of the form factors are all comparable with the experimental data. This successful application of chiral effective Lagrangian to relatively large momentum transfer make it possible to further investigation of hadron quantities at high $Q^2$.