Experimental Evidence for the Fermi Interaction in theβDecay ofO14andC10

Abstract

The $\ensuremath{\gamma}$-ray spectra of ${\mathrm{O}}^{14}$ and ${\mathrm{C}}^{10}$ have been investigated with a NaI scintillation spectrometer. A value of 2.30\ifmmode\pm\else\textpm\fi{}0.03 Mev was found for the ${\mathrm{O}}^{14}$ nuclear $\ensuremath{\gamma}$ ray. ${\mathrm{C}}^{10}$ has two $\ensuremath{\gamma}$ rays with energies 723\ifmmode\pm\else\textpm\fi{}15 and 1033\ifmmode\pm\else\textpm\fi{}30 kev; the number of quanta per disintegration are 0.99\ifmmode\pm\else\textpm\fi{}0.08 and 1.65\ifmmode\pm\else\textpm\fi{}0.20\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}2}$, respectively. The 1033-kev $\ensuremath{\gamma}$ ray is associated with a weak positron transition to the 1.74-Mev level in ${\mathrm{B}}^{10}$. There are less than ${10}^{\ensuremath{-}3}$ 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\ensuremath{\rightarrow}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 ${0.79}_{\ensuremath{-}0.13}^{+0.27}$, if one assumes $L\ensuremath{-}S$ coupling, and ${0.44}_{\ensuremath{-}0.07}^{+0.15}$ for $j\ensuremath{-}j$ coupling.