Identifying the spin trapped character of the $^{32}$Si isomeric state

Autor: Williams, J., Hackman, G., Starosta, K., Lubna, R. S., Choudhary, Priyanka, Srivastava, P. C., Andreoiu, C., Annen, D., Asch, H., Badanage, M. D. H. K. G., Ball, G. C., Beuschlein, M., Bidaman, H., Bildstein, V., Coleman, R., Garnsworthy, A. B., Greaves, B., Leckenby, G., Karayonchev, V., Martin, M. S., Natzke, C., Petrache, C. M., Radich, A., Raleigh-Smith, E., Rhodes, D., Russell, R., Satrazani, M., Spagnoletti, P., Svensson, C. E., Tam, D., Wu, F., Yates, D., Yu, Z.
Rok vydání: 2023
Předmět:
Druh dokumentu: Working Paper
Popis: The properties of a nanosecond isomer in $^{32}$Si, disputed in previous studies, depend on the evolution of proton and neutron shell gaps near the `island of inversion'. We have placed the isomer at 5505.2(2) keV with $J^{\pi} = 5^-$, decaying primarily via an $E3$ transition to the $2^+_1$ state. The $E3$ strength of 0.0841(10) W.u. is unusually small and suggests that this isomer is dominated by the $(\nu d_{3/2})^{-1} \otimes (\nu f_{7/2})^{1}$ configuration, which is sensitive to the $N=20$ shell gap. A newly observed $4^+_1$ state is placed at 5881.4(13) keV; its energy is enhanced by the $Z=14$ subshell closure. This indicates that the isomer is located in a `yrast trap', a feature rarely seen at low mass numbers.
Comment: Accepted, Physical Review C
Databáze: arXiv