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\ifmmode^\circ\else\textdegree\fi{} and 90\ifmmode^\circ\else\textdegree\fi{} 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\ifmmode\pm\else\textpm\fi{}1.0)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}27}$ ${\mathrm{cm}}^{2}$ ${\mathrm{steradian}}^{\ensuremath{-}1}$ 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 $n\ensuremath{-}p$ and $p\ensuremath{-}p$ forces are different.The $p\ensuremath{-}p$ scattering at high energy is even qualitatively different from $n\ensuremath{-}p$ scattering at comparable energy. In the $p\ensuremath{-}p$ scattering the presence of other than $S$-wave scattering is evidenced in the magnitude of the cross section but not in the angular dependence in the range 41\ifmmode^\circ\else\textdegree\fi{} to 90\ifmmode^\circ\else\textdegree\fi{} center of mass system.