The pseudo-scalar form factor of the nucleon, the sigma-like term, and theL0+amplitude for charged pion electro-production near threshold

The pseudo-scalar form factor, which represents the pseudo-scalar quark density distribution due to finite quark masses on the nucleon, is shown to manifest itself with the induced pseudo-scalar form factor in the L 0 + amplitude for the charged pion electro-production. Both form factors show their own peculiar momentum dependence. Under the approximation on which the Goldberger–Treiman relation holds, a sum of both form factors' contributions accounts for the t-channel contribution in the charged pion electro-production near threshold.