Analysis ofp+d→He3+X0Experiments

Analysis of ${\pi }^0$, ${\eta }^0$, and ${\omega }^0$ production by 2- and 3-GeV protons in the reaction $p+d\to {\mathrm{He}}^3+X^0$ leads to an understanding of the variation of these cross sections with respect to momentum transfer and yields information concerning the ${\mathrm{He}}^3$ form factor. It is shown that the observed missing-mass spectra at the $2\pi$ threshold, which deviates from phase space in this reaction (the ABC effect), can be explained using this momentum-transfer dependence of the ${\mathrm{He}}^3$ form factor.