Enhanced low-energy γ-decay probability - implications for r-process (n,γ) reaction rates


Enhanced low-energy γ-decay probability - implications for r-process (n,γ) reaction rates

Larsen, A. C.; Guttormsen, M.; Bello-Garrotte, F. L.; Bernstein, L. A.; Bleuel, D. L.; Bracco, A.; Brown, B. A.; Camera, F.; Crespo-Campo, L.; Frauendorf, S.; Goldblum, B. L.; Goriely, S.; Görgen, A.; Hadynska-Klek, K.; Hagen, T. W.; Harissopulos, S.; Kheswa, B. V.; Klintefjord, M.; Leoni, S.; Liddick, S. N.; Moretto, L. G.; Naqvi, F.; Perdikakis, G.; Renstrøm, T.; Rogers, A. M.; Rose, S. J.; Sahin, E.; Schwengner, R.; Siem, S.; Simon, A.; Spyrou, A.; Tveten, G. M.; Voinov, A.; Wiedeking, M.; Utsunomiya, H.

An unexpected enhancement in the average, reduced γ-decay strength at very low -transition energies has been observed in in f p-shell nuclei as well as in the Mo region. Very recently, it has showed up in 138 La, which is, so far, the heaviest nucleus to display this feature. In this work, we present an experimental and theoretical overview of the low-energy enhancement. In particular, experimental evidence for the dipole nature of the enhancement, and shell-model calculations indicating strong, low-energy M 1 transitions are shown. Possible implications of this low-energy enhancement on astrophysical (n,γ ) reaction rates of relevance for the r-process nucleosynthesis are discussed.

Keywords: Nuclear structure; nuclear reactions; gamma strength function; neutron capture; reaction rates

  • Open Access Logo Contribution to proceedings
    14th International Conference on Nuclear Reaction Mechanisms, 15.-19.06.2015, Varenna, Italien
    Proceedings of the 14th International Conference on Nuclear Reaction Mechanisms, Genf: CERN-Proceedings, ISBN 978-92-9083-418-2, 261-266

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Publ.-Id: 22472