Model dependence of peripheral NN phase parameters at medium energy

The model dependence of high $L$ partial waves in nucleon-nucleon scattering for $T_{\mathrm{lab}}=400-1000\mathrm{}$ MeV is studied. Unlike at low energy, model predictions are not unique. This is due to the delta isobar, which plays a major role in determining high $L$ inelasticities as well as real phase shifts. The differences between various model predictions are mainly due to the use of different delta propagators and delta vertex functions.