The generalized electromagnetic polarizabilities of the proton*

 

A fundamental property of the proton involves the system's response to an external electromagnetic (EM) field. It is characterized by the EM polarizabilities that describe how easily the charge and magnetization distributions inside the system are distorted by the EM field and the generalized polarizabilities that map out the resulting deformation of the densities in a proton subject to an EM field. They reveal unique information regarding the underlying system dynamics and provide a key for decoding the proton structure in terms of the theory of the strong interaction that binds its elementary quark and gluon constituents together. Of particular interest is a puzzle in the proton's electric generalized polarizability that remains unresolved for two decades. In this talk we will present new results of the proton GPs from JLab and will briefly discuss the prospects of future measurements.