Exotic Nuclear Decay of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">Ra</mml:mi></mml:mrow><mml:mprescripts/><mml:mrow/><mml:mrow><mml:mn>223</mml:mn></mml:mrow><mml:mrow/><mml:mrow/></mml:mmultiscripts></mml:mrow></mml:math>by Emission of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">C</mml:mi></mml:mrow><mml:mprescripts/><mml:mrow/><mml:mrow><mml:mn>14</mml:mn></mml:mrow><mml:mrow/><mml:mrow/></mml:mmultiscripts></mml:mrow></mml:math>Nuclei

The exotic nuclear decay of $^{223}\mathrm{Ra}$ by emission of $^{14}\mathrm{C}$ nuclei has been investigated by use of an intense radioactive $^{227}\mathrm{Ac}$ source and a magnetic spectrometer with a large solid angle. After a run of 5 d, a group of eleven events was observed at the expected location of $^{14}\mathrm{C}$ in a $\ensuremath{\Delta}E\ensuremath{-}E$ telescope calibrated with a $^{14}\mathrm{C}$ beam. A branching ratio of (5.5 \ifmmode\pm\else\textpm\fi{} 2.0) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}10}$ was measured for the emission of $^{14}\mathrm{C}$ nuclei relative to $\ensuremath{\alpha}$ particles from $^{223}\mathrm{Ra}$ in agreement with the previously reported ratio of (8.5 \ifmmode\pm\else\textpm\fi{} 2.5) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}10}$.