The pseudo scalar form factor of the nucleon, the sigma-like term, and   the $L_0^+$ 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 Goldberg-Treimann relation holds, a sum of both form factors' contributions accounts for the t-channel contribution in the charged pion electro-production near threshold. 
Myung Ki Cheoun and K.S. Kim