The mixing ratios for two gamma-ray transitions in ${\mathrm{C}}^{13}$ have been measured: For the transition $3.68\to 0$, $x\left(\frac{E2\mathrm{}}{M1\mathrm{}}\right)=-\left({{0.096}_{-0.021\mathrm{}}}^{+0.030\mathrm{}}\right)$ while for the transition $3.85\to 0$, $x\left(\frac{E3\mathrm{}}{M2\mathrm{}}\right)=+(0.12\mathrm{}\pm 0.03)$. The phase convention quoted by Poletti and Warburton is used. The phase of the mixing ratio for the 3.68 → 0 transition is compared with that for the mirror transition in ${\mathrm{N}}^{13}$ and with the phase of the mixing ratio for the transitions between ${\frac{3}{2}}^{-}$ and ${\mathrm{½}}^{-}$ hole states in ${\mathrm{N}}^{15}$ and ${\mathrm{O}}^{15}$. The 3.85 → 0, ${\frac{5}{2}}^{+}$ → ${\mathrm{½}}^{-}$ transition is also discussed and compared with the ${\frac{5}{2}}^{+}$ → ${\mathrm{½}}^{-}$ transitions in mass 15.

• Received 22 June 1966

DOI:https://doi.org/10.1103/PhysRev.151.812