Generalized polarizabilities of the nucleon in chiral effective theories

Using the techniques of chiral effective field theories we evaluate the so called “generalized polarizabilities,” which characterize the structure dependent components in virtual Compton scattering off the nucleon as probed in the electron scattering reaction $e\overrightarrow{N}{e}^{\prime }N\gamma .$ Results are given for both spin-dependent and spin-independent structure effects to $\mathcal{O}{(p}^3)$ in SU(2) heavy baryon chiral perturbation theory and to $\mathcal{O}\left({\epsilon }^3\right)$ in the SU(2) “small scale expansion.”