Proton-deuteron interactions at 970 MeV

Abstract

A high-pressure diffusion cloud chamber has been used to study the interactions of 970 MeV protons from the Birmingham synchrotron with deuterium. Analysis of the 569 collisions observed indicates that at this energy the deuteron behaves as if it were composed of two free nucleons. The properties of proton-proton and proton-neutron scattering have been determined on this assumption. An estimate is made of the extent of the 'shadowing' of each nucleon in the deuteron by the other. The partial cross-sections for p-p and p-n elastic scattering have been determined, as have also the values for the five possible single meson production processes. They have the following 'best' values: $ \matrix\format\l \\ (1)\ (p+p\rightarrow p+p)=25.9\pm \ 1\cdot 7\ \text{mb}, \\ (2)\ (p+n\rightarrow p+n)=16.2\pm \ 3\cdot 5\ \text{mb}, \\ (3)\ (p+p\rightarrow p+p+\pi ^{0})=5\cdot 4\pm \ 1\cdot 0\ \text{mb}, \\ (4)\ (p+p\rightarrow n+p+\pi ^{+})=15\cdot 6\pm \ 1\cdot 7\ \text{mb}, \\ (5)\ (p+n\rightarrow p+n+\pi ^{0})=14\cdot 3\pm \ 3\cdot 5\ \text{mb}, \\ (6)\ (p+n\rightarrow p+p+\pi ^{-})=2\cdot 7\pm \ 0\cdot 6\ \text{mb}, \\ (7)\ (p+n\rightarrow n+n+\pi ^{+})=4\cdot 3\pm \ 1\cdot 1\ \text{mb}. \endmatrix $ Double meson production and reactions involving secondary deuterons are not important. The cross-sections (1), (2), (3), (4) and (5) are consistent with values extrapolated from data at energies below 660 MeV by Russian workers. Knowledge of the other cross-sections (6) and (7) makes possible a test of the validity of the charge independence of nuclear forces. The present results are not in good agreement with this. The results for inelastic scattering indicate that, assuming charge independence, the formation of excited nucleons of isotopic spin $\frac{3}{2}$ does not dominate the process of pion production. This is also true for the Russian data. Twelve cases of double meson production were observed. The angular distribution of proton-neutron elastic scattering has the form expected from lower energy data.