  We present the first attempt to extract the scalar dipole dynamical
polarizabilities from proton real Compton scattering data below pion-production
threshold. The theoretical framework combines dispersion relations technique,
low-energy expansion and multipole decomposition of the scattering amplitudes.
The results are obtained with statistical tools that have never been applied so
far to Compton scattering data and are crucial to overcome problems inherent to
the analysis of the available data set.
