A new measurement is reported of the radiative branching ratio $\frac{{\Gamma }_{\mathrm{rad}}}{\Gamma }$ for the 7.655-MeV state of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$. This quantity is needed for calculations of stellar helium burning. Coincidences between ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ recoils of the proper energy and protons inelastically scattered from ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ signified the radiative decay of the 7.655-MeV state. A value of (4.30 ± 0.20) × ${10}^{-4\mathrm{}}$ was obtained for the branching ratio, compared with a recent measurement of (4.20 ± 0.22) × ${10}^{-4\mathrm{}}$ and the previous best value of (2.9 ± 0.3) × ${10}^{-4\mathrm{}}$.

NUCLEAR STRUCTURE ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, 7.655-MeV state; measured $\frac{{\Gamma }_{\mathrm{rad}}}{\Gamma }$. Stellar helium burning.

• Received 10 February 1975

DOI:https://doi.org/10.1103/PhysRevC.11.2063