Off - Shell Effects in Triton Binding - Energy and Form - Factor Calculations

Abstract

We calculate the triton binding energy and charge form factor for a set of phase-shift-equivalent, $S$-wave, spin-independent potentials. The Faddeev equations are solved by the method of Pad\'e approximants. We present a partial wave expansion for the triton form factor for a $J=0$ spatially symmetric wave function. A 6-MeV variation in triton binding energy results occurs for the potentials studied. All but 1 MeV of this off-shell variation is attributable to changes in the deuteron wave function. The relation between the triton binding energy and deuteron wave function is discussed. We find that the triton binding energy is sensitive to the relative amount of scale distortion in the momentum-space deuteron wave function. For the potentials studied, less binding in the triton is associated with deuteron wave functions that are more "compressed," i.e., fall off more rapidly in momentum space for $k<2$ ${\mathrm{fm}}^{\ensuremath{-}1}$. We also find that potentials that yield less binding in the triton (in worse agreement with experiment) yield a diffraction minimum in the form factor at smaller momentum transfer (in better agreement with experiment). The disparity between the binding-energy results and form-factor results with respect to experiment may indicate a role for three-body forces in the three-nucleon system.