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Electromagnetic form factors of proton and neutron, obtained from a new fit of data, are presented. The proton form factors are obtained from a simultaneous fit to the ratio µ p G Ep /G Mp determined from polarization transfer measurements and to ep elastic cross section data. Phenomenological two-photon exchange corrections are taken into account. The present fit for protons was performed in the kinematical region Q 2 ∈ (0, 6) GeV 2 . For both protons and neutrons we use the latest available data. For all form factors, the uncertainties and correlations of form factor parameters are investigated with the χ 2 method.

A careful reanalysis of both Argonne National Laboratory and Brookhaven National Laboratory data for weak single pion production is done. We consider deuteron nuclear effects and normalization (flux) uncertainties in both experiments. We demonstrate that these two sets of data are in good agreement. For the dipole parametrization of C A 5 (Q 2 ), we obtain C A 5 (0) = 1.19 ± 0.08, MA = 0.94 ± 0.03 GeV. As an application we present the discussion of the uncertainty of the neutral current 1π 0 production cross section, important for the T2K neutrino oscillation experiment.

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