Isospin symmetry in B(E2) values: Coulomb excitation study of 21Mg
Ruotsalainen, P., Henderson, J., Hackman, G., Sargsyan, G. H., Launey, K. D., Saxena, A., . . . Wu, C. Y. (2019). Isospin symmetry in B(E2) values: Coulomb excitation study of 21Mg. Physical Review C, 99 (5), 051301(R). doi:10.1103/physrevc.99.051301
Published inPhysical Review C
Cruz, S. |
Holl, M. |
Park, J. |
© 2019 American Physical Society
The Tz=−32 nucleus 21Mg has been studied by Coulomb excitation on 196Pt and 110Pd targets. A 205.6(1)-keV γ-ray transition resulting from the Coulomb excitation of the 52+ ground state to the first excited 12+ state in 21Mg was observed for the first time. Coulomb excitation cross-section measurements with both targets and a measurement of the half-life of the 12+ state yield an adopted value of B(E2;52+→12+)=13.3(4) W.u. A new excited state at 1672(1) keV with tentative 92+assignment was also identified in 21Mg. This work demonstrates a large difference in the B(E2;52+→12+) value between T=32, A=21 mirror nuclei. The difference is investigated in the shell-model framework employing both isospin conserving and breaking USD interactions and using modern ab initio nuclear structure calculations, which have recently become applicable in the sd shell.