ENERGY SENSITIVITY OF THE LOW-ENERGY PARAMETERS OF NEUTRON-PROTON SCATTERING FOR VARIOUS NUCLEON-NUCLEON POTENTIALS

The triplet and singlet low-energy parameters in the effective-range expansion for neutron-proton scattering were determined with the aid of the most popular modern realistic nucleon-nucleon potentials (Nijm I), (Nijm II) and (Reid93). We compared our results with the latest partial wave analysis experimental data from the SAID nucleon-nucleon database and newest values a(t), a(s), r(t) and r(s) parameters were presented. Our calculations based on these three potentials at incident neutron energy less than 60 KeV show that there are some discrepancies with experimental data. In order to decrease the discrepancy between our results and the experimental ones at very low energy, we suggest to include coupling terms S-3(1) + D-3(1) for constructing various realistic nuclear-force models. Furthermore, the calculated effective range expansions in this work are not very accurate for very low energy unless considering into account many terms v(n) in the expansions.