Upbend and M1 scissors mode in neutron-rich nuclei - consequences for r-process $$(n,\gamma )$$ reaction rates

Journal Article · Thu Jan 01 00:00:00 EST 2015 · Acta Physica Polonica. Series B

DOI:https://doi.org/10.5506/APhysPolB.46.509· OSTI ID:1256979

Larsen, A. C. ^[1]; Goriely, S. ^[2]; Bernstein, L. A. ^[3]; Bleuel, D. L. ^[4]; Bracco, A. ^[5]; Brown, B. A. ^[6]; Camera, F. ^[5]; Eriksen, T. K. ^[1]; Frauendorf, S. ^[7]; Giacoppo, F. ^[1]; Guttormsen, M. ^[1]; Gorgen, A. ^[1]; Harissopulos, S. ^[8]; Leoni, S. ^[5]; Liddick, S. N. ^[6]; Naqvi, F. ^[6]; Nyhus, H. T. ^[1]; Rose, S. J. ^[1]; Renstrom, T. ^[1]; Schwengner, R. ^[9] ; Siem, S. ^[1]; Spyrou, A. ^[6]; Tveten, G. M. ^[1]; Voinov, A. V. ^[10]; Wiedeking, M. ^[11]

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1. Univ. of Oslo, Oslo (Norway)
2. Institut d'Astronomie et d'Astrophysique, Brussels (Belgium)
3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of California, Berkeley, CA (United States)
4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
5. INFN, Milano (Italy); Univ. of Milano, Milano (Italy)
6. Michigan State Univ., East Lansing, MI (United States)
7. Univ. of Notre Dame, Notre Dame, IN (United States)
8. Institute of Nuclear Physics, Athens (Greece)
9. Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany)
10. Ohio Univ., Athens, OH (United States)
11. iThemba LABS, Somerset West (South Africa)

An enhanced probability for low-energy γ-emission (upbend, E < inf > γ < /inf > < 3 MeV) at high excitation energies has been observed for several light and mediummass nuclei close to the valley of stability. Also the M1 scissors mode seen in deformed nuclei increases the γ-decay probability for low-energy γ-rays (E < inf > γ < /inf > ≈ 2-3 MeV). These phenomena, if present in neutron-rich nuclei, have the potential to increase radiative neutron-capture rates relevant for the r-process. The experimental and theoretical status of the upbend is discussed, and preliminary calculations of (n,γ) reaction rates for neutronrich, mid-mass nuclei including the scissors mode are shown.

• Research Organization: Ohio Univ., Athens, OH (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: NA0001837; FG02-88ER40387; AC02-05CH11231
• OSTI ID: 1256979
• Alternate ID(s): OSTI ID: 1407301
• Journal Information: Acta Physica Polonica. Series B, Vol. 46, Issue 3; Conference: Zakopane Conference on Nuclear Physics Extremes of the Nuclear Landscape, Zakopane (Poland), 31 Aug - 7 Sep 2014; ISSN 0587-4254
• Publisher: Jagiellonian University
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
gamma strength
scissors mode