Fast-timing study of the l-forbidden 1/2(+) -> 3/2(+) M1 transition in Sn-129



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Fraile Prieto, Luis Mario and Vedia Fernández, María Victoria and Ibáñez García, Paula Beatriz and Paziy, Vadym and Pérez Liva, Mailyn and Picado, E. and Vidal, M. (2016) Fast-timing study of the l-forbidden 1/2(+) -> 3/2(+) M1 transition in Sn-129. Physical teview C, 93 (4). ISSN 0556-2813

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The levels in Sn-129 populated from the beta(-) decay of In-129 isomers were investigated at the ISOLDE facility of CERN using the newly commissioned ISOLDE Decay Station (IDS). The lowest 1/2(+) state and the 3/2(+) ground state in 129Sn are expected to have configurations dominated by the neutron s(1/2) (l = 0) and d(3/2) (l = 2) single-particle states, respectively. Consequently, these states should be connected by a somewhat slow l-forbidden M1 transition. Using fast-timing spectroscopy we havemeasured the half-life of the 1/2(+) 315.3-keV state, T-1/2 = 19(10) ps, which corresponds to a moderately fast M1 transition. Shell-model calculations using the CD-Bonn effective interaction, with standard effective charges and g factors, predict a 4-ns half-life for this level. We can reconcile the shell-model calculations to the measured T-1/2 value by the renormalization of the M1 effective operator for neutron holes.

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© 2016 Amer Physical Soc.
We express our deep appreciation to the late Professor Henryk Mach, who was the initiator of this investigation. He was an inspiring collaborator, mentor, and leader in developing the beta gamma gamma (t) fast-timing technique. His memory and accomplishments will always be with us. This work was partially supported by the Spanish MINECO through Projects No. FPA2012-32443, No. FPA2013-41267-P, and CPAN Consolider (Project No. CSD-2007-00042), and by Romanian IFA Grant CERN/ISOLDE. It was also partly funded by the NuPNET network FATIMA (PRI-PIMNUP-2011-1338), by FWO-Vlaanderen (Belgium), by GOA/2010/010 (BOF KU Leuven), and by the Interuniversity Attraction Poles Programme initiated by the Belgian Science PolicyOffice (BriX network P7/12). Support from Grupo de Fisica Nuclear (GFN-UCM), Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale (PRIN) Grant No. 2001024324 01302, German BMBF under Contracts No. 05P12PKFNE and No. 05P15PKCIA, the U.K. Science and Technology Facilities Council, and the European Union Seventh Framework through ENSAR (Contract No. 262010) is also acknowledged. Fast-timing electronics were provided by the Fast Timing Collaboration, the ISOLDE Decay Station collaboration, and MASTICON.

Uncontrolled Keywords:Picosecond lifetime measurements; Neutron rich nuclei
Subjects:Sciences > Physics > Nuclear physics
ID Code:37870
Deposited On:01 Jun 2016 15:12
Last Modified:10 Dec 2018 14:57

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