Electroproduction of π0-mesons on protons at very low values of vertical stroke q2 vertical stroke

The electroproduction of π0-mesons on protons has been measured with electrons of 1.7 and 2.1 GeV energy in the region of the nucleon resonances at W=1.400-2.000 MeV at rather low values of vertical stroke q2 vertical stroke =0.01-0.1 GeV2 but at high values of the nucleon recoil vertical stroke t vertical stroke approx. equal to0.6-2.2 GeV2. Up to Wapprox. equal to1.650 MeV the cross section for π0-production with virtual photons of vertical stroke q2 vertical stroke approx. equal to0.03 GeV2 is only slightly smaller than that with real photons. For Wapprox. >=1.700 MeV the cross section at vertical stroke q2 vertical stroke approx. equal to0.03 GeV2 is on average a factor of 2 smaller than that at q2=0 but only slightly higher than that at vertical stroke q2 vertical stroke approx. equal to0.3-1 GeV2. (orig./WB)