Search for a2π0Resonance near 730 MeV inπ+dInteractions

Abstract

In an analysis of 229 000 pictures of ${\pi }^{+}$ at incident momenta of 1.1 to 2.3 GeV/c in the deuterium-filld 72-in. bubble chamber, we have identified 8386 examples of the reaction ${\pi }^{+}d\to pp+\mathrm{neutrals}$. An application of the impulse approximation gives 4965 events of the type ${\pi }^{+}n\to p+\mathrm{neutrals}$. At a small momentum transfer (≤0.2 and 0.08 ${\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c}}^2$) to the neutrals system, we find no direct evidence for an enhancement near the reported position of the ${\epsilon }^0$, ≈730 MeV. A detailed subtraction of $3{\pi }^0$ and $N^{*}\mathrm{}\left(1238\right)\mathrm{}$ background based on cross sections from other experiments results in a $2{\pi }^0$ mass spectrum, which is found to be in agreement with the direct experimental results of Corbett et al. (in shape only) and with the prediction of Malamud and Schlein (in shape and magnitude). The latter is based on an analysis of the $\rho$-decay asymmetry. Consequently, we interpret our results to be consistent with the existence of the ${\epsilon }^0$, the parameters for which result from the analysis by Malamud and Schlein.