First two members of the $K^{\pi }=0^{-}$ band in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$

In an alpha capture experiment on an ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ gas target, the $3^{-}$, 7.156 MeV state in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ has been observed to decay to the $1^{-}$, 5.782 MeV and the $4^{+}$, 4.248 MeV states with gamma ray branches of 45 ± 5% and 55 ± 5%, respectively. The strengths of the 1374 and 2908 keV transitions were deduced to be $B\left(E2\mathrm{}\right)=51\mathrm{}\pm 8$ W.u. and $B\left(E1\mathrm{}\right)=79\mathrm{}\pm 9$ μ W.u., respectively. The strongly enhanced $E2\mathrm{}$ rate for the $3^{-}$ to $1^{-}$ transition is convincing evidence for these two states being the first members of this $K^{\pi }=0^{-}$ band in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$. From resonance scattering experiments, the alpha widths for these two states were determined to be 28 ± 3 eV and 8.1 ± 0.3 keV, respectively; values in agreement with cluster calculations of alpha widths in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$.

NUCLEAR REACTIONS Measured $\sigma (E, \theta )$ for ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}(\alpha , \alpha ){}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and $\sigma \left(E_R\right)$ for ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}(\alpha , \gamma ){}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$; deduced ${\Gamma }_{\alpha }$ for $E_x=5.782\mathrm{} \mathrm{and} 7.156$ MeV and radiative transition rates from $E_x=7.156\mathrm{}$ MeV.