Measurement of the N + 2 s 2 p 3 5 S 2 o level lifetime using a heavy-ion storage ring

The slow electric-dipole intercombination decay of the ${2s2p}^{3}{}^{5}{S}_{2}^{o}$ level in the C-like ion ${\mathrm{N}}^{+},$ which appears in the auroral airglow spectrum, has been optically observed from ions circulating in a storage ring. A result of $5.88\ifmmode\pm\else\textpm\fi{}0.03 \mathrm{ms}$ was obtained for the natural lifetime of this level. This represents an improvement in precision by a factor of 10 compared to previous radio-frequency and electrostatic ion trap work and is in slight disagreement with the latest theoretical values.