Analysis of the 213-MeV Proton-Proton Scattering Data

Modified phase-shift analyses have been made of the 213-MeV Rochester data, with a statistical argument used to eliminate three of the data. The methods of obtaining the least-squares fit to the data, and of choosing the phase shifts to be searched upon are examined in some detail. Thirteen free phases are preferred and most of these are found to have very small uncertainties. Several of the data subgroups give unexpectedly low contributions to ${\chi }^2$, but are still influential in limiting the phase-shift standard deviations. All models so far proposed for the proton-proton interaction give poorer fit to the data by an order of magnitude than does the modified phase analysis. The solution of the type 2 of Stapp, Ypsilantis, and Metropolis has a ${\chi }^2$ probability of less than 1%. The pion-nucleon coupling constant could only be roughly evaluated, giving qualitative evidence for the one pion exchange mechanism. Estimates have been made of the effectiveness of several possible extensions of the measurements.