Determination of the Nucleon's Isotopic Spectral Functions

Abstract

We employ the method of exact inversion, discussed in an earlier paper, to determine the nucleon's isotopic spectral functions from their corresponding real form factors. Specific analytic expressions, as suggested by previous pole fits, are used for the real form factors and these give spectral functions that have all the required analytic properties. The constraint that the electric and magnetic form factors are equal at the threshold for proton-antiproton annihilation into an electron-positron pair is used throughout. We find that the complex proton's form factors are zero at the annihilation threshold and using this observation we compare our results with the predictions of the internal symmetry theories.