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

Abstract

An enhanced probability for low-energy γ-emission ( upbend, Eγ < 3 MeV) at high excitation energies has been observed for several light and medium-mass 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 γ ≈ 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. Furthermore, the experimental and theoretical status of the upbend is discussed, and preliminary calculations of (n,γ) reaction rates for neutron-rich, mid-mass nuclei including the scissors mode are shown.

Authors:
 [1];  [2];  [3];  [4];  [5];  [6];  [5];  [1];  [7];  [1];  [1];  [1];  [8];  [5];  [6];  [6];  [1];  [1];  [1];  [9] more »;  [1];  [6];  [1];  [10];  [11] « less
  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)
Publication Date:
Research Org.:
Ohio Univ., Athens, OH (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1256979
Alternate Identifier(s):
OSTI ID: 1407301
Grant/Contract Number:
NA0001837; FG02-88ER40387; AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Acta Physica Polonica. Series B
Additional Journal Information:
Journal Volume: 46; Journal Issue: 3; Conference: Zakopane Conference on Nuclear Physics Extremes of the Nuclear Landscape, Zakopane (Poland), 31 Aug - 7 Sep 2014; Journal ID: ISSN 0587-4254
Publisher:
Jagiellonian University
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; gamma strength; scissors mode

Citation Formats

Larsen, A. C., Goriely, S., Bernstein, L. A., Bleuel, D. L., Bracco, A., Brown, B. A., Camera, F., Eriksen, T. K., Frauendorf, S., Giacoppo, F., Guttormsen, M., Gorgen, A., Harissopulos, S., Leoni, S., Liddick, S. N., Naqvi, F., Nyhus, H. T., Rose, S. J., Renstrom, T., Schwengner, R., Siem, S., Spyrou, A., Tveten, G. M., Voinov, A. V., and Wiedeking, M. Upbend and M1 scissors mode in neutron-rich nuclei - consequences for r-process $(n,\gamma )$ reaction rates. United States: N. p., 2015. Web. doi:10.5506/APhysPolB.46.509.
Larsen, A. C., Goriely, S., Bernstein, L. A., Bleuel, D. L., Bracco, A., Brown, B. A., Camera, F., Eriksen, T. K., Frauendorf, S., Giacoppo, F., Guttormsen, M., Gorgen, A., Harissopulos, S., Leoni, S., Liddick, S. N., Naqvi, F., Nyhus, H. T., Rose, S. J., Renstrom, T., Schwengner, R., Siem, S., Spyrou, A., Tveten, G. M., Voinov, A. V., & Wiedeking, M. Upbend and M1 scissors mode in neutron-rich nuclei - consequences for r-process $(n,\gamma )$ reaction rates. United States. doi:10.5506/APhysPolB.46.509.
Larsen, A. C., Goriely, S., Bernstein, L. A., Bleuel, D. L., Bracco, A., Brown, B. A., Camera, F., Eriksen, T. K., Frauendorf, S., Giacoppo, F., Guttormsen, M., Gorgen, A., Harissopulos, S., Leoni, S., Liddick, S. N., Naqvi, F., Nyhus, H. T., Rose, S. J., Renstrom, T., Schwengner, R., Siem, S., Spyrou, A., Tveten, G. M., Voinov, A. V., and Wiedeking, M. Thu . "Upbend and M1 scissors mode in neutron-rich nuclei - consequences for r-process $(n,\gamma )$ reaction rates". United States. doi:10.5506/APhysPolB.46.509. https://www.osti.gov/servlets/purl/1256979.
@article{osti_1256979,
title = {Upbend and M1 scissors mode in neutron-rich nuclei - consequences for r-process $(n,\gamma )$ reaction rates},
author = {Larsen, A. C. and Goriely, S. and Bernstein, L. A. and Bleuel, D. L. and Bracco, A. and Brown, B. A. and Camera, F. and Eriksen, T. K. and Frauendorf, S. and Giacoppo, F. and Guttormsen, M. and Gorgen, A. and Harissopulos, S. and Leoni, S. and Liddick, S. N. and Naqvi, F. and Nyhus, H. T. and Rose, S. J. and Renstrom, T. and Schwengner, R. and Siem, S. and Spyrou, A. and Tveten, G. M. and Voinov, A. V. and Wiedeking, M.},
abstractNote = {An enhanced probability for low-energy γ-emission (upbend, Eγ < 3 MeV) at high excitation energies has been observed for several light and medium-mass 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 (Eγ ≈ 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. Furthermore, the experimental and theoretical status of the upbend is discussed, and preliminary calculations of (n,γ) reaction rates for neutron-rich, mid-mass nuclei including the scissors mode are shown.},
doi = {10.5506/APhysPolB.46.509},
journal = {Acta Physica Polonica. Series B},
number = 3,
volume = 46,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 2015},
month = {Thu Jan 01 00:00:00 EST 2015}
}

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