β+decays of very proton-richsd-shell nuclei

Allowed ${\mathrm{\beta }}^{+}$-decay branches of very proton-rich sd-shell nuclei up to the proton drip line are calculated by the complete sd-space shell model. The ${\mathrm{\beta }}^{+}$-decay half-lives calculated with the global quenching factor (${\mathit{g}}_{\mathit{A}}^{\mathrm{eff}}$/${\mathit{g}}_{\mathit{A}}$ ${)}^2$=0.60 are in reasonable agreement with existing experimental data. However, considerable deviations of the quenching factor from the global value are obtained in a comparison of the theoretical and experimental ft values in the large-Q-value window. Probable candidates for the β-delayed two-proton emission are suggested with the predicted ${\mathrm{\beta }}^{+}$-decay branching strengths to states above the proton-emission threshold energy.