THE PS-P SYSTEM IN THE COUPLED STATIC MODEL

The close-coupling equations for the Ps-p system are solved for a mode l calculation including the H(1s) and Ps(1s) states. Comparisons betwe en complete and second-order solutions of the Lippmann-Schwinger revea l that the second Born approximation for the Ps(1s)-p entrance channel only becomes a reasonable approximation at energies as high as 200 eV . The phaseshifts for the Ps(1s) entrance channel are inverted using t he Marchenko and Gel'fand-Levitan methods. The phase equivalent invers ion potential for L = 0 is repulsive at large distances with a deep we ll at small distances and is consistent with the interpretation of the resonance as a 'coupled channel shape resonance'. The inversion poten tials for the L = 1 and 2 partial waves are seen to be characterized b y an attractive well at small distances.