Novel ΔJ=1 Sequence in Ge78: Possible Evidence for Triaxiality

Forney, A. M.; Walters, W. B.; Chiara, C. J.; Janssens, R. V. F.; Ayangeakaa, A. D.; Sethi, J.; Harker, J.; Alcorta, M.; Carpenter, M. P.; Gurdal, G.; Hoffman, C. R.; Kay, B. P.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; McCutchan, Elizabeth A.; Rogers, A. M.; Seweryniak, D.; Stefanescu, I.; Zhu, S.

doi:10.1103/PhysRevLett.120.212501

Title: Novel $Δ J = 1$ Sequence in ${}^{78}{Ge}$ : Possible Evidence for Triaxiality

Journal Article · Tue May 22 00:00:00 EDT 2018 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.120.212501· OSTI ID:1438428

Forney, A. M. ^[1]; Walters, W. B. ^[1]; Chiara, C. J. ^[2]; Janssens, R. V. F. ^[3]; Ayangeakaa, A. D. ^[4]; Sethi, J. ^[1]; Harker, J. ^[5]; Alcorta, M. ^[6]; Carpenter, M. P. ^[7]; Gurdal, G. ^[8]; Hoffman, C. R. ^[7]; Kay, B. P. ^[7]; Kondev, F. G. ^[7]; Lauritsen, T. ^[7]; Lister, C. J. ^[9]; McCutchan, Elizabeth A. ^[10]; Rogers, A. M. ^[9]; Seweryniak, D. ^[7]; Stefanescu, I. ^[5]; Zhu, S. ^[7]

Univ. of Maryland, College Park, MD (United States)
Univ. of Maryland, College Park, MD (United States); Argonne National Lab. (ANL), Argonne, IL (United States); U.S. Army Research Lab., Adelphi, MD (United States)
Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of North Carolina, Chapel Hill, NC (United States)
Argonne National Lab. (ANL), Argonne, IL (United States); United States Naval Academy, Annapolis, MD (United States)
Univ. of Maryland, College Park, MD (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Argonne National Lab. (ANL), Argonne, IL (United States); TRIUMF, Vancouver, BC (Canada)
Argonne National Lab. (ANL), Argonne, IL (United States)
Argonne National Lab. (ANL), Argonne, IL (United States); Millsaps College, Jackson, MS (United States)
Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of Massachusetts, Lowell, MA (United States)
Argonne National Lab. (ANL), Argonne, IL (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)

A sequence of low-energy levels in ^$7832$Ge₄₆ 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 groundstate 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.

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Research Organization:: Brookhaven National Lab. (BNL), Upton, NY (United States); Argonne National Lab. (ANL), Argonne, IL (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Nuclear Physics (NP); USDOE Office of Science - Office of Nuclear Physics

Grant/Contract Number:: SC0012704; AC02-06CH11357; AC02-98CH10886; FG02-94ER40834; FG02-97ER41041; FG02-97ER41033

OSTI ID:: 1438428

Alternate ID(s):: OSTI ID: 1438290; OSTI ID: 1493714

Report Number(s):: BNL-203652-2018-JAAM; BNL-203358-2018-JAAM; PRLTAO; TRN: US1900437

Journal Information:: Physical Review Letters, Vol. 120, Issue 21; ISSN 0031-9007

Publisher:: American Physical Society (APS)Copyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 13 works

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References (37)

One- and two-phonon wobbling excitations in triaxial 165Lu Schönwaßer, G.; Hübel, H.; Hagemann, G. B. Physics Letters B, Vol. 552, Issue 1-2 https://doi.org/10.1016/S0370-2693(02)03095-2	journal	January 2003
Rotational states in even atomic nuclei Davydov, A. S.; Filippov, G. F. Nuclear Physics, Vol. 8 https://doi.org/10.1016/0029-5582(58)90153-6	journal	September 1958
Identification of deformed intruder states in semi-magic ${}^{70}{Ni}$ Chiara, C. J.; Weisshaar, D.; Janssens, R. V. F. Physical Review C, Vol. 91, Issue 4 https://doi.org/10.1103/PhysRevC.91.044309	journal	April 2015
“Anomalous” signature splitting in the yrast band of the odd-odd 160Ho nucleus Pinston, J. A.; Andre, S.; Barneoud, D. Physics Letters B, Vol. 137, Issue 1-2 https://doi.org/10.1016/0370-2693(84)91103-1	journal	March 1984
Signatures of γ softness or triaxiality in low energy nuclear spectra Zamfir, N. V.; Casten, R. F. Physics Letters B, Vol. 260, Issue 3-4 https://doi.org/10.1016/0370-2693(91)91610-8	journal	May 1991
The Shell-Model Code NuShellX@MSU Brown, B. A.; Rae, W. D. M. Nuclear Data Sheets, Vol. 120 https://doi.org/10.1016/j.nds.2014.07.022	journal	June 2014
Breakdown of $K$ Selection in ${}^{178}{Hf}$ Hayes, A. B.; Cline, D.; Wu, C. Y. Physical Review Letters, Vol. 96, Issue 4 https://doi.org/10.1103/PhysRevLett.96.042505	journal	February 2006
A Composite Chiral Pair of Rotational Bands in the Odd- $A$ Nucleus ${}^{135}{N d}$ Zhu, S.; Garg, U.; Nayak, B. K. Physical Review Letters, Vol. 91, Issue 13 https://doi.org/10.1103/PhysRevLett.91.132501	journal	September 2003
The role of triaxiality in the ground states of even-even neutron-rich Ru isotopes Shannon, J. A.; Phillips, W. R.; Durell, J. L. Physics Letters B, Vol. 336, Issue 2 https://doi.org/10.1016/0370-2693(94)90238-0	journal	September 1994
Evidence for the Wobbling Mode in Nuclei Ødegård, S. W.; Hagemann, G. B.; Jensen, D. R. Physical Review Letters, Vol. 86, Issue 26 https://doi.org/10.1103/PhysRevLett.86.5866	journal	June 2001
${}^{72, 74, 76}{Ge}$ by the ( $t$ , $p$ ) reaction Lebrun, C.; Guilbault, F.; Ardouin, D. Physical Review C, Vol. 19, Issue 4 https://doi.org/10.1103/PhysRevC.19.1224	journal	April 1979
Level lifetime measurements and the structure of neutron-rich ${}^{78}{Ge}$ Chou, W. -T.; Brenner, D. S.; Casten, R. F. Physical Review C, Vol. 47, Issue 1 https://doi.org/10.1103/PhysRevC.47.157	journal	January 1993
Shell structure in nuclei Ragnarsson, Ingemar; Gösta Nilsson, Sven; Sheline, Raymond K. Physics Reports, Vol. 45, Issue 1 https://doi.org/10.1016/0370-1573(78)90004-2	journal	August 1978
Triaxiality near the 110 Ru ground state from Coulomb excitation Doherty, D. T.; Allmond, J. M.; Janssens, R. V. F. Physics Letters B, Vol. 766 https://doi.org/10.1016/j.physletb.2017.01.031	journal	March 2017
Surface Oscillations in Even-Even Nuclei Wilets, Lawrence; Jean, Maurice Physical Review, Vol. 102, Issue 3 https://doi.org/10.1103/PhysRev.102.788	journal	May 1956
Collective motion and deformed shell structure in the doubly even fp shell nuclei Larsson, S. E.; Leander, G.; Ragnarsson, I. Nuclear Physics A, Vol. 261, Issue 1 https://doi.org/10.1016/0375-9474(76)90042-7	journal	April 1976
${}^{76}{Ge} (t, p) {}^{78}{Ge}$ reaction Mateja, J. F.; Medsker, L. R.; Fortune, H. T. Physical Review C, Vol. 17, Issue 6 https://doi.org/10.1103/PhysRevC.17.2047	journal	June 1978
Triaxiality in quadrupole deformed nuclei Wu, C. Y.; Cline, D. Physical Review C, Vol. 54, Issue 5 https://doi.org/10.1103/PhysRevC.54.2356	journal	November 1996
Shape coexistence and the role of axial asymmetry in 72Ge Ayangeakaa, A. D.; Janssens, R. V. F.; Wu, C. Y. Physics Letters B, Vol. 754 https://doi.org/10.1016/j.physletb.2016.01.036	journal	March 2016
Nuclear structure of ${}^{76}{Ge}$ from inelastic neutron scattering measurements and shell model calculations Mukhopadhyay, S.; Crider, B. P.; Brown, B. A. Physical Review C, Vol. 95, Issue 1 https://doi.org/10.1103/PhysRevC.95.014327	journal	January 2017
Quadrupole collectivity and shapes of OsPt nuclei Wu, C. Y.; Cline, D.; Czosnyka, T. Nuclear Physics A, Vol. 607, Issue 2 https://doi.org/10.1016/0375-9474(96)00181-9	journal	September 1996
Spontaneous symmetry breaking in rotating nuclei Frauendorf, Stefan Reviews of Modern Physics, Vol. 73, Issue 2 https://doi.org/10.1103/RevModPhys.73.463	journal	June 2001
Triaxial deformation in odd-Z light rare-earth nuclei Hamamoto, I.; Sagawa, H. Physics Letters B, Vol. 201, Issue 4 https://doi.org/10.1016/0370-2693(88)90593-X	journal	February 1988
Identification of the $g_{9 / 2}$ -proton bands in the neutron-rich ${}^{71, 73, 75, 77}{Ga}$ nuclei Stefanescu, I.; Walters, W. B.; Janssens, R. V. F. Physical Review C, Vol. 79, Issue 6 https://doi.org/10.1103/PhysRevC.79.064302	journal	June 2009
Relative transition probabilities between rotational levels of non-axial nuclei Davydov, A. S.; Rostovsky, V. S. Nuclear Physics, Vol. 12, Issue 1 https://doi.org/10.1016/0029-5582(59)90127-0	journal	June 1959
Nature of $γ$ deformation in Ge and Se nuclei and the triaxial projected shell model description Bhat, G. H.; Dar, W. A.; Sheikh, J. A. Physical Review C, Vol. 89, Issue 1 https://doi.org/10.1103/PhysRevC.89.014328	journal	January 2014
Evidence for Multiple Chiral Doublet Bands in ${}^{133}{Ce}$ Ayangeakaa, A. D.; Garg, U.; Anthony, M. D. Physical Review Letters, Vol. 110, Issue 17 https://doi.org/10.1103/PhysRevLett.110.172504	journal	April 2013
Transverse Wobbling in ${}^{135}\Pr$ Matta, J. T.; Garg, U.; Li, W. Physical Review Letters, Vol. 114, Issue 8 https://doi.org/10.1103/PhysRevLett.114.082501	journal	February 2015
Nuclear Data Sheets for A = 78 Farhan, Ameenah R.; Singh, Balraj Nuclear Data Sheets, Vol. 110, Issue 9 https://doi.org/10.1016/j.nds.2009.08.001	journal	September 2009
The GAMMASPHERE Lee, I-Yang Nuclear Physics A, Vol. 520 https://doi.org/10.1016/0375-9474(90)91181-P	journal	December 1990
Staggering in γ-band energies and the transition between different structural symmetries in nuclei McCutchan, E. A.; Bonatsos, Dennis; Zamfir, N. V. Physical Review C, Vol. 76, Issue 2 https://doi.org/10.1103/PhysRevC.76.024306	journal	August 2007
Decay of mass-separated ${}^{78}{Ga}$ to levels in even-even ${}^{78}{Ge}$ Lewis, D. A.; Hill, John C.; Wohn, F. K. Physical Review C, Vol. 22, Issue 5 https://doi.org/10.1103/PhysRevC.22.2178	journal	November 1980
Wobbling mode in ${}^{167}{Ta}$ Hartley, D. J.; Janssens, R. V. F.; Riedinger, L. L. Physical Review C, Vol. 80, Issue 4 https://doi.org/10.1103/PhysRevC.80.041304	journal	October 2009
Evidence for rigid triaxial deformation at low energy in $^{76}$ Ge Toh, Y.; Chiara, C. J.; McCutchan, E. A. Physical Review C, Vol. 87, Issue 4 https://doi.org/10.1103/PhysRevC.87.041304	journal	April 2013
Low-spin states and the non-observation of a proposed 2202-keV, $0^{+}$ isomer in $^{68}$ Ni Chiara, C. J.; Broda, R.; Walters, W. B. Physical Review C, Vol. 86, Issue 4 https://doi.org/10.1103/PhysRevC.86.041304	journal	October 2012
Evidence for Multiple Chiral Doublet Bands in $^{133}$Ce Ayangeakaa, A. D.; Garg, U.; Anthony, M. D. arXiv https://doi.org/10.48550/arxiv.1302.0401	text	January 2013
Shape coexistence and the role of axial asymmetry in $^{72}$Ge Ayangeakaa, A. D.; Janssens, R. V. F.; Wu, C. Y. arXiv https://doi.org/10.48550/arxiv.1603.04484	text	January 2016

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