Novel analysis of chiral loop effects in the generalized Gerasimov–Drell–Hearn sum rule

We study the chiral loop corrections to the generalized Gerasimov–Drell–Hearn sum rule of the nucleon for finite photon virtuality in the framework of a Lorentz-invariant formulation of baryon chiral perturbation theory. We perform a complete one-loop calculation and obtain significant differences to previously found results based on the heavy baryon approach for the proton and neutron spin-dependent forward Compton amplitudes.