Isospin Conservation in the ReactionC12(α, d)N14

Cross sections for the formation of 24 states between 0 and 13-MeV excitation in ${\mathrm{N}}^{14}$ via the ${\mathrm{C}}^{12}(\alpha , d){\mathrm{N}}^{14}$ reaction were measured. Six $T=1\mathrm{}$ levels could have been observed if the $\Delta T=0\mathrm{}$ selection rule for this reaction had been violated. None of these $T=1\mathrm{}$ levels were observed to be excited. From the upper limits on their cross sections, isospin impurities in the wave functions of the 8.06-, 9.51-, and 10.43-MeV $T=1\mathrm{}$ levels were deduced to be less than 50, 15, and 24%, respectively. These experimental upper limits are still some-what larger than crude theoretical estimates of the isospin mixing induced by the Coulomb interaction.