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

R. Lică, H. Mach, L. M. Fraile, A. Gargano, M. J. G. Borge, N. Mărginean, C. O. Sotty, V. Vedia, A. N. Andreyev, G. Benzoni, P. Bomans, R. Borcea, L. Coraggio, C. Costache, H. De Witte, F. Flavigny, H. Fynbo, L. P. Gaffney, P. T. Greenlees, L. J. Harkness-BrennanM. Huyse, P. Ibáñez, D. S. Judson, J. Konki, A. Korgul, T. Kröll, J. Kurcewicz, S. Lalkovski, I. Lazarus, M. V. Lund, M. Madurga, R. Mărginean, I. Marroquín, C. Mihai, R. E. Mihai, A. I. Morales, E. Nácher, A. Negret, R. D. Page, J. Pakarinen, S. Pascu, V. Paziy, A. Perea, M. Pérez-liva, E. Picado, V. Pucknell, E. Rapisarda, P. Rahkila, F. Rotaru, J. A. Swartz, O. Tengblad, P. Van Duppen, M. Vidal, R. Wadsworth, W. B. Walters, N. Warr

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7 Citations (Scopus)


The levels in Sn129 populated from the β− decay of In129 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 Sn129 are expected to have configurations dominated by the neutron s1/2 (l=0) and d3/2 ( 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 have measured the half-life of the 1/2+ 315.3-keV state, T1/2= 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 T1/2 value by the renormalization of the M1 effective operator for neutron holes.
Original languageEnglish
Article number044303
Number of pages7
JournalPhysical Review C
Issue number4
Publication statusPublished - 4 Apr 2016


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