Isospin Purity and Delayed-Proton Decay: ${}^{17}{Ne}$ and ${}^{33}{Ar}$

β

-delayed proton and

γ

-ray measurements have been used to study the decay of

{}^{17}{Ne}

and

{}^{33}{Ar}

. Their half-lives have been measured as 109.0 ± 1.0 and 173.0 ± 2.0 msec, respectively, and absolute

ft

values have been determined for their

β

-decay branches. Precise level energies have been measured in

{}^{17}F

and

{}^{33}{Cl}

, and an earlier discrepancy concerning energies in

{}^{17}F

has been resolved. The

log ft

value for the superallowed decay branch of

{}^{17}{Ne}

has been measured to be

{3.29}_{- 0.07}^{+ 0.04}

, which indicates an isospin purity of ≥95% for the lowest

T = \frac{3}{2}

state in

{}^{17}F

. In addition, the antianalog configuration is located in

{}^{17}F

and is shown to be the most probable source of the small isospin mixing present in the analog state in that nucleus. The

log ft

value measured for the superallowed decay branch from

{}^{33}{Ar}

was 3.34 ± 0.05, a value which suggests an impurity of ∼10% in the lowest

T = \frac{3}{2}

state in

{}^{33}{Cl}

. There is circumstantial evidence that this mixing occurs with four

T = \frac{1}{2}

states which lie within 350 keV of the analog state.

This publication has 50 references indexed in Scilit:

Isospin Purity and Delayed-Proton Decay:Ne17andAr33