Experimental Evidence for the Fermi Interaction in theβDecay ofO14andC10

Abstract

The $\gamma$-ray spectra of ${\mathrm{O}}^{14}$ and ${\mathrm{C}}^{10}$ have been investigated with a NaI scintillation spectrometer. A value of 2.30±0.03 Mev was found for the ${\mathrm{O}}^{14}$ nuclear $\gamma$ ray. ${\mathrm{C}}^{10}$ has two $\gamma$ rays with energies 723±15 and 1033±30 kev; the number of quanta per disintegration are 0.99±0.08 and 1.65±0.20×${10}^{-2\mathrm{}}$, respectively. The 1033-kev $\gamma$ ray is associated with a weak positron transition to the 1.74-Mev level in ${\mathrm{B}}^{10}$. There are less than ${10}^{-3\mathrm{}}$ transitions per disintegration to the 2.15-Mev level of ${\mathrm{B}}^{10}$. By combining our results with those of heavy particle reactions and using the predictions of the charge multiplet theory on the energies of the analog states, we conclude that the ${\mathrm{O}}^{14}$ decay and the weak ${\mathrm{C}}^{10}$ branch to the 1.74-Mev level of ${\mathrm{B}}^{10}$ are allowed favored 0→0 (no) transitions. From the ${\mathrm{C}}^{10}$ data we find that the ratio of the Fermi to the Gamow-Teller interactions constants ($\frac{{G_F}^2}{{G_{\mathrm{GT}}}^2}$) is ${0.79}_{-0.13\mathrm{}}^{+0.27\mathrm{}}$, if one assumes $L-S$ coupling, and ${0.44}_{-0.07\mathrm{}}^{+0.15\mathrm{}}$ for $j-j$ coupling.