Nucleon-nucleon partial-wave analysis to 1100 MeV.

Abstract

Comprehensive analyses of nucleon-nucleon elastic-scattering data below 1100 MeV laboratory kinetic energy are presented. The data base from which an energy-dependent solution and 22 single-energy solutions are obtained consists of 7223 pp and 5474 np data. A resonancelike structure is found to occur in the $^{1}\mathrm{D}_{2}$, $^{3}\mathrm{F}_{3}$, $^{3}\mathrm{P}_{2}$${\mathrm{\ensuremath{-}}}^{3}$${\mathrm{F}}_{2}$, and $^{3}\mathrm{F}_{4}$${\mathrm{\ensuremath{-}}}^{3}$${\mathrm{H}}_{4}$ partial waves; this behavior is associated with poles in the complex energy plane. The pole positions and residues are obtained by analytic continuation of the ``production'' piece of the T matrix obtained in the energy-dependent solution. The new phases differ somewhat from previously published VPI solutions, especially in I=0 waves above 500 MeV, where np data are very sparse. The partial waves are, however, based upon a significantly larger data base and reflect correspondingly smaller errors. The full data base and solution files can be obtained through a computer scattering analysis interactive dial-in (SAID) system at VPI, which also exists at many institutions around the world and which can be transferred to any site with a suitable computer system. The SAID system can be used to modify solutions, plan experiments, and obtain any of the multitude of predictions which derive from partial-wave analyses of the world data base.