Nucleon-Nucleon Scattering with Inelastic Unitarity

The effects of inelastic unitarity on dynamical calculation of nucleon-nucleon scattering are studied, using the $\frac{N}{D}$ formalism for partial-wave amplitudes modified to take into account reaction channels by means of the inelastic factor $\eta$. The equations are solved for the ${}_{}{}^1{}_{}{}^{}D_2^{}{}_{}{}^{}$ amplitude for which the inelastic scattering is known (for laboratory kinetic energies $E_L\lesssim 800$ MeV) and large. We use left-hand-cut Born terms determined by Scotti and Wong. The calculated (real part of the) phase shift $\delta$ agrees very closely with the Scotti-Wong results for $E_L\lesssim 200$ (for reasonable choices of the high-energy behavior of $\eta$) but deviates appreciably at higher energy, peaking at ≈400-500 MeV and going negative at ≳1 BeV.