Novel ΔJ=1 Sequence in ^{78}Ge: Possible Evidence for Triaxiality.

Autor: Forney AM; Department of Chemistry and Biochemistry, University of Maryland College Park, College Park, Maryland 20742, USA., Walters WB; Department of Chemistry and Biochemistry, University of Maryland College Park, College Park, Maryland 20742, USA., Chiara CJ; Department of Chemistry and Biochemistry, University of Maryland College Park, College Park, Maryland 20742, USA.; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Janssens RVF; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.; Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA and Triangle Universities Nuclear Laboratory, Duke University, Durham, North Carolina 27708, USA., Ayangeakaa AD; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.; Department of Physics, United States Naval Academy, Annapolis, Maryland 21402, USA., Sethi J; Department of Chemistry and Biochemistry, University of Maryland College Park, College Park, Maryland 20742, USA., Harker J; Department of Chemistry and Biochemistry, University of Maryland College Park, College Park, Maryland 20742, USA.; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Alcorta M; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.; TRIUMF, Vancouver, British Columbia V6T 2A3, Canada., Carpenter MP; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Gürdal G; Nuclear Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.; Physics Department, Millsaps College, Jackson, Mississippi 39202, USA., Hoffman CR; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Kay BP; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Kondev FG; Nuclear Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Lauritsen T; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Lister CJ; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.; Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854, USA., McCutchan EA; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.; National Nuclear Data Center, Brookhaven National Laboratory, Upton, New York 11973, USA., Rogers AM; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.; Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, Massachusetts 01854, USA., Seweryniak D; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Stefanescu I; Department of Chemistry and Biochemistry, University of Maryland College Park, College Park, Maryland 20742, USA.; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Zhu S; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Jazyk: angličtina
Zdroj: Physical review letters [Phys Rev Lett] 2018 May 25; Vol. 120 (21), pp. 212501.
DOI: 10.1103/PhysRevLett.120.212501
Abstrakt: A sequence of low-energy levels in _{32}^{78}Ge_{46} has been identified with spins and parity of 2^{+}, 3^{+}, 4^{+}, 5^{+}, and 6^{+}. Decays within this band proceed strictly through ΔJ=1 transitions, unlike similar sequences in neighboring Ge and Se nuclei. Above the 2^{+} level, members of this sequence do not decay into the ground-state band. Moreover, the energy staggering of this sequence has the phase that would be expected for a γ-rigid structure. The energies and branching ratios of many of the levels are described well by shell-model calculations. However, the calculated reduced transition probabilities for the ΔJ=2 in-band transitions imply that they should have been observed, in contradiction with the experiment. Within the calculations of Davydov, Filippov, and Rostovsky for rigid-triaxial rotors with γ=30°, there are sequences of higher-spin levels connected by strong ΔJ=1 transitions which decay in the same manner as those observed experimentally, yet are calculated at too high an excitation energy.
Databáze: MEDLINE