ELECTROMAGNETIC NUCLEON FORM-FACTORS AND THEIR SPECTRAL FUNCTIONS IN SOLITON MODELS

It is demonstrated that in simple soliton models essential features of the electro-magnetic nucleon form factors observed over three orders of magnitude in momentum transfer t are naturally reproduced. The anal ysis shows that three basic ingredients are required: an extended obje ct, partial coupling to vector mesons, and relativistic recoil correct ions. We use for the extended object the standard skyrmion, one vector meson propagator for both isospin channels, and the relativistic boos t to the Breit frame. Continuation to timelike t leads to quite stable results for the spectral functions in the regime from the 2- or 3-pio n threshold to about two rho masses, Especially the onset of the conti nuous part of the spectral functions at threshold can be reliably dete rmined and there are strong analogies to the results imposed on disper sion theoretic approaches by the unitarity constraint.