Field Corrections to Neutron-Proton Scattering in a New Mixed Meson Theory

The principal relativistic correction to neutron-proton scattering has been computed to fourth order for nonrelativistic energies by calculating the matrix elements using the Feynman method and then subtracting off the appropriate order Born approximation to the Yukawa potential. A new meson theory was used, namely a mixture of pseudovector mesons and pseudoscalar mesons with pseudovector coupling; it is shown that by suitable choice of the coupling constants the divergent terms could be eliminated in all orders (disregarding possible electromagnetic couplings). The mesonic field corrections to neutron-proton scattering were found to be of order $\frac{\mu }{M}$ smaller than the static Yukawa potential cross section; in practical applications, they could be treated as a perturbing potential to the static Yukawa interaction.