Isovector parity mixing in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ investigated via the ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$(p→,${\mathrm{\alpha }}_0$${)}^{12}$C resonance reaction

The parity- and isospin-forbidden ${\mathrm{\alpha }}_0$ decay from ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}_{}^{\mathrm{*}}{}_{}{}^{}$(${\mathit{J}}^{\mathrm{\pi }}$=$2^{\mathrm{-}}$, T=1, ${\mathit{E}}_{\mathit{x}}$=12.9686 MeV) to ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(g.s.) has been investigated theoretically. Considering various strong and weak interaction models the longitudinal ${\mathit{A}}_{\mathit{L}}$ and the irregular transverse ${\mathit{A}}_{\mathit{b}}$ analyzing powers of the reaction ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$(p→,${\mathrm{\alpha }}_0$${)}^{12}$C have been calculated in the energy range of the $2^{\mathrm{-}}$ resonance in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}_{}^{\mathrm{*}}{}_{}{}^{}$. Energy anomalies for the expected interference effects, relevant for experiments, have been found to be ${\mathit{A}}_{\mathit{L}}$=1.1×${10}^{\mathrm{-}5}$ and ${\mathit{A}}_{\mathit{b}}$=0.9×${10}^{\mathrm{-}5}$ at θ=90° and ${\mathit{A}}_{\mathit{L}}$=1.4×${10}^{\mathrm{-}5}$ and ${\mathit{A}}_{\mathit{b}}$=0.2×${10}^{\mathrm{-}5}$ at θ=150° based on a conservative value of 0.1 eV for the parity-nonconservation matrix element. A proposal for an experimental investigation is sketched.