LOW-ENERGY LIMIT OF THE γN-SCATTERING AMPLITUDE AND CROSSING SYMMETRY
The low energy limit for the γN scattering amplitude is derived with the aid of single-nucleon invariant amplitudes. Subsequent terms in ν for Q2 = 0 and the expression for the limiting value of the first derivative in Q2 as Q2 → 0 can be obtained by taking into account the conditions of crossing symmetry.