Electromagnetic Mass Shifts, Commutator Ambiguities, and Exponentially Falling Form Factors

A connection is suggested between the ambiguities in the definition of the equal-time commutator [${{\dot{J}}_{\mu }}^{\mathrm{em}}(0, \overrightarrow{\mathrm{x}})$, ${J_{\nu }}^{\mathrm{em}}\mathrm{}\left(0\right)\mathrm{}$] and the experimental indications of an exponentially falling electromagnetic form factor for the nucleon. On this basis, a resolution is proposed of the difficulty of current-algebra models which appear to give divergent expressions for the electromagnetic mass shifts of hadrons.