Paper detail

Reanalysis of ep Elastic Scattering Data in Terms of Proton Electromagnetic Formfactors

We have made the comparison of three parametrizations of the proton electromagnetic form factors in the space-like region using the largest data set on $e^{\pm} p$ elastic scattering ever used. All models have a correct analytical structure with a minimal set of well known singularities. For the first time an effective two-pion intermediate coulombic bound state (pionium) was included into GVMD for nucleon formfactors. For the proton charge radius an estimate derived from our best fits is as follows: r_E^p [\rm fm] = 0.897 \pm 0.002(exp) \pm 0.001(norm) \pm 0.003(models). The traditional ``model independent'' fit by quadratic polynomial gives, in our estimation technology, a much cruder estimate r^p_{E,polinomial} [\rm fm] = 0.887 \pm 0.006(exp) \pm 0.096(norm). Both estimates are closer to the value estimated from the recent hydrogen Lamb shift measurements.