Structure analysis of the virtual Compton scattering amplitude at low energies
Abstract
We analyze virtual Compton scattering (VCS) off the nucleon at low energies in a covariant, model-independent formalism. We define a set of invariant functions which, for the structure-dependent part of the VCS amplitude, is free of poles and kinematical zeros. The covariant treatment naturally allows to implement the constraints due to Lorentz and gauge invariance, crossing symmetry, and the discrete symmetries. In particular, when applied to the photon electroproduction reaction, charge-conjugation symmetry in combination with nucleon crossing generates four relations among the ten originally proposed generalized polarizabilities of the nucleon. We perform a 1/M expansion of the VCS amplitude near the real-photon point and show how the generalized polarizabilities can be extracted from such an expansion. Finally, we discuss the real-photon limit including the spin-independent as well as the spin-dependent polarizabilities.Keywords
All Related Versions
This publication has 0 references indexed in Scilit: