Two identical particles can scatter elastically by both single photon and single Z⁰ exchange. Calculate the typical squared energy– momentum transfer q² between them for a distance of closest approach of (a) 1 fm and (b) 10⁻³fm in their centre-of-mass frame. Assuming that the intrinsic strengths of the fundamental weak and electromagnetic interactions are approximately equal, compare the relative sizes of the invariant (scattering) amplitudes for Z⁰ and photon exchange processes at these two energy–momentum transfers.