The energy spectra of deuterons from the reaction ${\mathrm{C}}^{12}(\alpha , d){\mathrm{N}}^{14}$ have been measured. The reaction was induced by 47.5-Mev helium ions. Angular distributions are given for the deuteron groups corresponding to formation of the ground state and 3.95-Mev level of ${\mathrm{N}}^{14}$.

Formation of the 2.31-Mev 0+, $T=1\mathrm{}$ level of ${\mathrm{N}}^{14}$ was not observed; the cross section was less than 3% of the cross section for formation of the 1+, $T=0\mathrm{}$ ground state. It is suggested that this cannot be interpreted as strong evidence for the conservation of isotopic spin for two reasons. First, several well-known $T=0\mathrm{}$ levels were not populated to an observable extent. Second, the reaction leading to the $T=1\mathrm{}$ level would involve a transition from a 0+ level to a 0+ level, and such transitions in ($\alpha , d$) or ($d, \alpha$) reactions involve difficulties with angular momentum and parity conservation in addition to nonconservation of isotopic spin, which requires $\Delta T=0\mathrm{}$.

• Received 15 August 1960

DOI:https://doi.org/10.1103/PhysRev.120.2162