Double Meson Production in Proton-Deuteron Collisions

In a previous publication (Abashian et al., Phys. Rev. Letters, 5: 258(1960)) measurements were reported on the momentum spectra of He/sup 3/ and H/ sup 3/ nuclei produced in collisions of 740-Mev protons with deuterons. The He/ sup 3/ spectrum exhibited an anomaly in the form of a peak in the region corresponding to double pion production. For reactions resulting in He/sup 3/, the two pions (or particle) can be in isotopic spin states 0 or 1; if a R/sup 3/ nucleus results, only 1 = 1 is allowed. The experiment was repeated with a new arrangement which enabled both the He/sup 3/ and the H/sup 3/ spectra to be measured with improved resolution and accuracy. It is concluded that the anomaly must be assigned an isotopic spin I = O. (L.T.W.)