학술논문
Identifying the spin trapped character of the $^{32}$Si isomeric state
Document Type
Working Paper
Author
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.
Source
Subject
Language
Abstract
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
Comment: Accepted, Physical Review C