Proton-Proton Scattering at 340 Mev

Abstract

Measurements of the proton-proton differential scattering cross section using 340-Mev protons show a cross section approximately constant between 41° and 90° in the center of mass system. Two methods of counting the scattered protons have been used. The first method uses a counter telescope to count the scattered protons. The second method utilizes coincidences between counters which record the two protons involved in a single scattering process. The first method gives slightly higher cross sections; the average value of the differential cross section is (5.5±1.0)×${10}^{-27\mathrm{}}$ ${\mathrm{cm}}^2$ ${\mathrm{steradian}}^{-1\mathrm{}}$ in the center of mass system. Although the scattering appears isotropic it is larger than can be accounted for with pure $S$-scattering. There is a strong suggestion, but no positive proof, that $n-p$ and $p-p$ forces are different.