Antiproton-proton partial-wave analysis below 925 MeV/c

Abstract

A partial-wave analysis of all p¯p scattering data below 925 MeV/c antiproton laboratory momentum is presented. The method used is adapted from the Nijmegen phase-shift analyses of pp and np scattering data. We solve the Schrödinger equation for the coupled p¯p and n¯n channels where the long- and intermediate-range interactions are described by a theoretically well-founded potential. This gives the rapid variations of the scattering amplitudes with energy. This potential consists of the Coulomb potential with the main relativistic correction, the magnetic-moment interaction, the one-pion-exchange potential, and the heavy-boson exchanges of the Nijmegen one-boson-exchange potential. Slow variations of the amplitudes due to short-range interactions, including the coupling to mesonic annihilation channels, are parametrized by an energy-dependent, complex boundary condition, specified at a radius of r=1.3 fm. The Nijmegen 1993 p¯p database, consisting of 3646 p¯p scattering data, is presented and discussed. The best fit to this database results in ${\mathrm{\chi }}_{\min }^2$/${\mathit{N}}_{\mathrm{data}}$=1.043. This good fit to the data shows that the Nijmegen long- and intermediate-range potential is essentially correct. The pseudovector coupling constant of the charged pion to nucleons is determined to be ${\mathit{f}}_{\mathit{c}}^2$=0.0732(11) at the pion pole, where the error is statistical.