From a 150 000-photograph exposure, we analyzed the $\overline{p}d\to \overline{p}{p}_{s}n$ reaction, $p_s$ denoting a proton stopping in the deuterium-filled bubble chamber. Choosing kinematical regions in which the $p_s$ can be recognized as a spectator, we studied the $\overline{p}n\to \overline{p}n$ process. From the observed $\overline{p}n$ diffraction peak, we obtained an exponential slope for the four-momentum-transfer distribution of $b_n=9.4\mathrm{}\pm 0.8$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{-2\mathrm{}}$, the elastic $\overline{p}n$ cross section being estimated as ${\sigma }_e\left(\overline{p}n\right)=16.5\mathrm{}\pm 2.4$ mb. The present values in conjunction with those obtained at ≈1.8 and 3.5 GeV/c show that in this region $b_n$ and ${\sigma }_e\left(\overline{p}n\right)$ decrease with increasing incident momentum. We compared our data with the reactions $\mathrm{np}\to \mathrm{np}$ at ≈5.4 GeV/c and $\overline{p}p\to \overline{p}p$ at 5.7 GeV/c. The $\overline{p}n\to \overline{p}n$ and $\mathrm{np}\to \mathrm{np}$ differential cross sections exhibit a crossover phenomenon while $\overline{p}p$ and $\overline{p}n$ elastic scattering show an isospin dependence. We also analyzed the $\overline{p}d\to \overline{p}{p}_{s}n$ reaction by means of the Glauber formalism.

• Received 27 June 1974

DOI:https://doi.org/10.1103/PhysRevD.10.3573