The Counting of Generalized Polarizabilities

Abstract

We demonstrate a concise method to enumerate the number of generalized polarizabilities---quantities characterizing the independent observables in singly-virtual Compton scattering---for a target particle of arbitrary spin s. By using crossing symmetry and J^{PC} conservation, we show that this number is (10s+1+delta_{s,0}).

Comments: 10 pages, revtex4, no figures. Version to appear in Phys. Rev. D. Paper now divided into sections and clarifying comments added, but physics content unchanged