Trinucleon charge form factor

Abstract

The trinucleon charge form factors are studied for various nuclear interaction models with possible three-body force and meson-exchange-current effects included. A unitary transformation method of generating three-body forces is discussed. Various meson-exchange effects, including pair and recoil currents as well as that of the $\pi \mathrm{NN}$ vertex function, are investigated. The calculations show that the strong potential dependence of the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ charge form factor in the impulse approximation diminishes considerably when meson-exchange effects are included. Exchange effects in ${}_{}{}^3{}_{}{}^{}\mathrm{H}$ are smaller than in ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and do not reduce the potential dependence. By including meson-exchange currents and three-body forces, good fits to the available ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^3{}_{}{}^{}\mathrm{H}$ form factor data for $0.5 {\mathrm{fm}}^{-2\mathrm{}}\le q^2\le 12 {\mathrm{fm}}^{-2\mathrm{}}$ are obtained without sacrificing a satisfactory triton binding energy. The position of the diffraction minimum is correctly predicted and the height of the second maximum is improved to about half of the experimental value.