Study of antiproton-proton annihilations using the topological-cross-section differences betweenp¯pandppinteractions at 48.9 GeV/c

The multiplicity-cross-section differences $\Delta {\sigma }_n$ between $\overline{p}p$ and $\mathrm{pp}$ interactions are determined and are compared with measured annihilations and $\Delta {\sigma }_n$ at other energies. To the extent that these cross-section differences measure the values of ${\sigma }_n^A$, the topological cross sections for annihilations, we present evidence for a decided break from a single-cluster-model prediction for the parameter $f_2^{A_{--}}$. Alternatively, a picture of precocious Koba-Nielsen-Olesen scaling in $\overline{p}p$ annihilations leads to a reasonably good representation of $f_2^{A_{--}}$ vs $〈n_{-}^A〉$ over the whole measured range. We find $〈n^A〉=7.57\mathrm{}\pm 0.31$, $D^A=2.77\mathrm{}\pm 0.10$, $f_2^{A_{--}}=-1.86\mathrm{}\pm 0.20$, and $\frac{〈n^A〉}{D}=2.73\mathrm{}\pm 0.15$. Finally we observe a remarkable agreement with theoretical prediction for $R_n^{*}=\frac{\Delta {\sigma }_n}{{\sigma }_{n+2\mathrm{}}\mathrm{}\left(\mathrm{pp}\right)\mathrm{}}$, an experimental ratio based on a strict application of the counting rules for quark duality diagrams, and we thereby find evidence that in the topological-cross-section difference $\Delta {\sigma }_n$ the small nonannihilation contribution becomes progressively more negligible as $n$ increases.