Nucleon Polarizabilities and Spin Sum-rules
Sam Hoblit
Brookhaven National Laboratory
Polarizabilities measure the strengths of transient dipole moments
induced in the nucleon by the electromagnetic field of the photon
during Compton scattering and describe the dynamical rearrangement
of the constituent charges, magetic moments and spins. Unpolarized photon
scattering has been used at several laboratories to study the six
polarizabilities and the current status will be reviewed. Additional
sensitivity to both the proton and neutron spin polarizabilities can
be achieved through double polarization experiments, where both the
incoming photon and target nucleon are polarized. The program of
double polarization experiments at LEGS will be outlined.