Electromagnetic and weak transitions in the seven-nucleon systems

H. Walliser, Q. K. K. Liu, H. Kanada, and Y. C. Tang
Phys. Rev. C 28, 57 – Published 1 July 1983
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Abstract

Electromagnetic M1 and E2 transitions in the seven-nucleon systems, the He3(α, γ)Be7 radiative-capture problem, and the electron-capture reaction of Be7 into Li7 are studied. The wave functions employed are from a previous single-channel resonating-group calculation which yielded satisfactory results for the He3 +α and H3 +α scattering cross sections and polarizations. With no adjustable parameters, the calculated B(M1) and B(E2) values for transitions between the ground and first excited states of Li7 or Be7 are found to agree rather well with values empirically determined. The B(E2) study shows, in particular, that the nuclei Li7 and Be7 must have strong collective features, which are describable in terms of α plus three-nucleon clustering. The cross-section factor S(0), important in astrophysical considerations, is determined to have a value between 0.5 and 0.6 keV b. For the electron-capture reaction, the calculated value of the branching ratio to the first excited state of Li7 is 10.31%, which is in very good agreement with the measured value of 10.36±0.10% reported prior to 1982.

NUCLEAR REACTIONS He3(α, γ), Be7(e), Li7(γ);; calculated capture cross section, logft, B(M1) and B(E2) with resonating-group wave functions.

  • Received 4 March 1983

DOI:https://doi.org/10.1103/PhysRevC.28.57

©1983 American Physical Society

Authors & Affiliations

H. Walliser*

  • School of Physics, University of Minnesota, Minneapolis, Minnesota 55455 and Universität Gesamthochschule Siegen, Fachbereich Physik, 59 Siegen, Federal Republic of Germany

Q. K. K. Liu

  • Hahn-Meitner-Institut für Kernforschung, Berlin, Federal Republic of Germany

H. Kanada

  • Department of Physics, Niigata University, Niigata, Japan

Y. C. Tang

  • School of Physics, University of Minnesota, Minneapolis, Minnesota 55455

  • *Permanent address: Universität Gesamthochschule Siegen, Fachbereich Physik, 59 Seigen, Federal Republic of Germany.

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Vol. 28, Iss. 1 — July 1983

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