Separable potential for the neutron-proton system

Description of intermediate- and short-range NN nuclear force within a covariant effective field theory

“…This description can be compared to the fit quality for the phase shifts given by a purely phenomenological separable interaction (of conventional type) of Graz group [52]. The latter model includes more than twenty five free parameters to fit the phase shifts in the same channels until 500 MeV only.…”

On the relativistic3D1partial-wave contribution to the bound three-nucleon system

“…The Graz-II kernels of interaction [5] As it is seen from the table 1 kernels with different p D can give results for binding energy both bigger and smaller than the experimental value. The relativistic results are systematically higher then nonrelativistic ones to about 3%.…”

“…In the paper [4] only S partial-states were considered for the one-rank kernel. In this paper the relativistic 3 D 1 partial-wave is added into formalism using the three-rank Graz-II kernel [5].…”

Relativistic multirank interaction kernels of the neutron–proton system

“…In the discussion of the 1 S + 0 channel the nonrelativistic Graz II [31], as an alternative model with a separable kernel, is also presented.…”

“…The form factors in the interaction kernel had no poles on a real axis in the relative energy complex plane [31,32]. However, after the construction of a relativistic generalization such poles appeared [30].…”