Publication Date:
2012-06-23
Description:
The shell structure of atomic nuclei is associated with 'magic numbers' and originates in the nearly independent motion of neutrons and protons in a mean potential generated by all nucleons. During beta(+)-decay, a proton transforms into a neutron in a previously not fully occupied orbital, emitting a positron-neutrino pair with either parallel or antiparallel spins, in a Gamow-Teller or Fermi transition, respectively. The transition probability, or strength, of a Gamow-Teller transition depends sensitively on the underlying shell structure and is usually distributed among many states in the neighbouring nucleus. Here we report measurements of the half-life and decay energy for the decay of (100)Sn, the heaviest doubly magic nucleus with equal numbers of protons and neutrons. In the beta-decay of (100)Sn, a large fraction of the strength is observable because of the large decay energy. We determine the largest Gamow-Teller strength so far measured in allowed nuclear beta-decay, establishing the 'superallowed' nature of this Gamow-Teller transition. The large strength and the low-energy states in the daughter nucleus, (100)In, are well reproduced by modern, large-scale shell model calculations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Hinke, C B -- Bohmer, M -- Boutachkov, P -- Faestermann, T -- Geissel, H -- Gerl, J -- Gernhauser, R -- Gorska, M -- Gottardo, A -- Grawe, H -- Grebosz, J L -- Krucken, R -- Kurz, N -- Liu, Z -- Maier, L -- Nowacki, F -- Pietri, S -- Podolyak, Zs -- Sieja, K -- Steiger, K -- Straub, K -- Weick, H -- Wollersheim, H-J -- Woods, P J -- Al-Dahan, N -- Alkhomashi, N -- Atac, A -- Blazhev, A -- Braun, N F -- Celikovic, I T -- Davinson, T -- Dillmann, I -- Domingo-Pardo, C -- Doornenbal, P C -- de France, G -- Farrelly, G F -- Farinon, F -- Goel, N -- Habermann, T C -- Hoischen, R -- Janik, R -- Karny, M -- Kaskas, A -- Kojouharov, I M -- Kroll, Th -- Litvinov, Y -- Myalski, S -- Nebel, F -- Nishimura, S -- Nociforo, C -- Nyberg, J -- Parikh, A R -- Prochazka, A -- Regan, P H -- Rigollet, C -- Schaffner, H -- Scheidenberger, C -- Schwertel, S -- Soderstrom, P-A -- Steer, S J -- Stolz, A -- Strmen, P -- England -- Nature. 2012 Jun 20;486(7403):341-5. doi: 10.1038/nature11116.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Physik Department E12, Technische Universitat Munchen, D-85748 Garching, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22722192" target="_blank"〉PubMed〈/a〉
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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