Parity of the First Unbound State inN14

A weak radiative decay from the proton-unbound level at 7.966-MeV excitation in ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ has been observed by coincident detection of protons and $\gamma$ rays from the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^3{}_{}{}^{}\mathrm{He}, p\gamma ){}_{}{}^{14}{}_{}{}^{}\mathrm{N}$. Using the previously known decay scheme the width ratio $\frac{{\Gamma }_{\gamma }}{\Gamma }$ is measured as (0.7±0.2)% from the observed coincidence yield. This result together with the reported value of $\frac{\omega {\Gamma }_p{\Gamma }_{\gamma }}{\Gamma }$ implies $\mathrm{}(2J+1)\mathrm{}{\Gamma }_p=12.6\mathrm{}\pm 3.6$ eV. Comparison of the present value of ${\Gamma }_p$ with measurements involving the reaction ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}({}_{}{}^3{}_{}{}^{}\mathrm{He}, d){}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ implies $l_p=2\mathrm{}$ for the (${}_{}{}^3{}_{}{}^{}\mathrm{He}$, $d$) transition leading to the 7.966-MeV state, and consequently establishes the parity of that state as negative.