Isospin symmetry in B(E2) values: Coulomb excitation study of Mg 21

P. Ruotsalainen, J. Henderson, G. Hackman, G. H. Sargsyan, K. D. Launey, A. Saxena, P. C. Srivastava, S. R. Stroberg, T. Grahn, J. Pakarinen, G. C. Ball, R. Julin, P. T. Greenlees, J. Smallcombe, C. Andreoiu, N. Bernier, M. Bowry, M. Buckner, R. Caballero-Folch, A. ChesterS. Cruz, L. J. Evitts, R. Frederick, A. B. Garnsworthy, M. Holl, A. Kurkjian, D. Kisliuk, K. G. Leach, E. McGee, J. Measures, D. Mücher, J. Park, F. Sarazin, J. K. Smith, D. Southall, K. Starosta, C. E. Svensson, K. Whitmore, M. Williams, C. Y. Wu

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

The Tz=-32 nucleus Mg21 has been studied by Coulomb excitation on Pt196 and Pd110 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 Mg21 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 Mg21. 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.

Original languageEnglish (US)
Article number051301
JournalPhysical Review C
Volume99
Issue number5
DOIs
StatePublished - May 6 2019

Funding

Acknowledgments. This work has been supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), The Canada Foundation for Innovation and the British Columbia Knowledge Development Fund. TRIUMF receives federal funding via a contribution agreement through the National Research Council of Canada. The work at LLNL is under Contract No. DE-AC52-07NA27344. The work at JYFL-ACCLAB has been supported by the Academy of Finland under the Finnish Center of Excellence Programme (2012–2017). The work at Colorado School of Mines has been supported by the U.S. Department of Energy under Grant No. DE-SC0017649. This work has been partly supported by the U.S. National Science Foundation (OIA-1738287, ACI-1713690). This work benefited from computing resources provided by Blue Waters (supported by NSF OCI-0725070 and ACI-1238993, and the State of Illinois) and LSU ( www.hpc.lsu.edu ).

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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