AXIAL AND PSEUDOSCALAR NUCLEON FORM-FACTORS FROM LOW-ENERGY PION ELECTROPRODUCTION

The cross section for exclusive pi+ electroproduction on the proton ha s been measured near threshold for the first time at two different val ues of the virtual photon polarization (epsilon is similar to 0.2 and epsilon is similar to 0.7). Using the low energy theorem for this reac tion we deduce the axial and pseudoscalar weak form factors G(A) and G (P) at Absolute value of t = 0.073, 0.139, and 0.179 (GeV/c)2. The slo pe of G(A) agrees with the value obtained in neutrino experiments. G(P ) satisfies the pion pole dominance hypothesis, which is thus verified for the first time in this range of transfer.