Sensitivity of Low-Energy Three-Body Properties to the Off-Shell Two-BodytMatrix

Abstract

Direct modifications are made to the off-shell two-body $t$ matrices which are used as input to the Faddeev-Lovelace equations for the three-body bound state and for scattering below breakup. The $t$ matrices are modified when either momentum argument exceeds a particular value, in a manner which will maintain off-shell unitarity when it is important. In this way, we are able to test the dependence of these three-body properties on different regions of the off-shell momenta. We find a strong sensitivity for both momenta less than 2 ${\mathrm{fm}}^{-1\mathrm{}}$; weak, potential-dependent sensitivity when either argument is between 2 and 5 ${\mathrm{fm}}^{-1\mathrm{}}$, and essentially no dependence if either argument exceeds 5 ${\mathrm{fm}}^{-1\mathrm{}}$.