Charged particle and pi0 multiplicity distributions and the annihilation properties of $\overline{p}$p interactions at 70 GeV/c

The elastic and inelastic pp cross sections at 70 GeV/c have been determined in an experiment performed at CERN using BEBC equipped with a TST. The topological cross sections were measured and the moments of the inelastic multiplicity distribution are (n/sub c/)=6.16+or-0.09, (n/sub c/)/D=2.04+or-0.05 and f/sub 2//sup cc/=2.97+or-0.03. The average number of Dalitz pairs per inelastic event is (3.12+or-0.09) *10/sup -2/. Assuming that these all arise from\pi^{0} decay the average\pi^{0} multiplicity is (n/sub\pi/)=2.71+or-0.14. The pp- pp cross section differences lead to an annihilation cross section sigma /sub A/=4.42+or-0.41 mb and the moments of the annihilation multiplicity distribution are (n/sub A/)=8.0+or-0.3, (n/sub A/) /D=2.5+or-0.2 and f/sub 2//sup A--/=-1.4+or-0.3. An independent check of sigma /sub A/ was made by investigating fast forward charged and neutral secondary interactions in the TST and in the surrounding neon- hydrogen mixture, and gives a value sigma /sub A/=5.0+or-1.6 mb. The ratio of fast n to p production in non-annihilation interactions at 70 GeV/c is found to be 0.45+or-0.11.