The reactions ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}(\alpha , p){}_{}{}^{34}{}_{}{}^{}\mathrm{S}$ and ${}_{}{}^{35}{}_{}{}^{}\mathrm{Cl}(\alpha , p){}_{}{}^{38}{}_{}{}^{}\mathrm{Ar}$ have been used to study the $E0\mathrm{}$ $\pi$ decays of the ${}_{}{}^{34}{}_{}{}^{}\mathrm{S}$(3.91 MeV, $0^{+}$) and ${}_{}{}^{38}{}_{}{}^{}\mathrm{Ar}$(3.38 MeV, $0^{+}$) states to the ground state. The $E0\mathrm{}$ branching ratios $\frac{{\Gamma }_{\pi }}{\Gamma }$ were measured to be (0.38 ± 0.06) × ${10}^{-3\mathrm{}}$ and (6.6 ± 1.0) × ${10}^{-3\mathrm{}}$, respectively. When these values are combined with the available lifetime of these states, $E0\mathrm{}$ matrix elements ${〈M〉}_{\pi }=(1.55\mathrm{}\pm 0.15)$ ${\mathrm{fm}}^2$ (${}_{}{}^{34}{}_{}{}^{}\mathrm{S}$) and (2.26 ± 0.21) ${\mathrm{fm}}^2$ (${}_{}{}^{38}{}_{}{}^{}\mathrm{Ar}$) are obtained.

NUCLEAR REACTIONS ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}(\alpha , p)$, $E=7.60\mathrm{}$ MeV; ${}_{}{}^{35}{}_{}{}^{}\mathrm{Cl}(\alpha , p)$, $E=7.67\mathrm{}$ MeV; ${}_{}{}^{34}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{38}{}_{}{}^{}\mathrm{Ar}$ measured $E0\mathrm{}$ branching ratios. Deduced $E0\mathrm{}$ matrix elements. Natural targets.

• Received 24 April 1975

DOI:https://doi.org/10.1103/PhysRevC.12.1103