Lifetime measurements of excited states in 172Pt and the variation of quadrupole transition strength with angular momentum

B. Cederwall, M. Doncel, Ö. Aktaş, A. Ertoprak, R. Liotta, C. Qi, T. Grahn, D.M. Cullen, B.S. Nara Singh, D. Hodge, M. Giles, S. Stolze, H. Badran, T. Braunroth, T. Calverley, D.M. Cox, Y.D. Fang, P.T. Greenlees, J. Hilton, E. Ideguchi & 21 others R. Julin, S. Juutinen, M. Kumar Raju, H. Li, H. Liu, S. Matta, V. Modamio, J. Pakarinen, P. Papadakis, J. Partanen, C.M. Petrache, P. Rahkila, P. Ruotslainen, M. Sandzelius, J. Saren, C. Scholey, J. Sorri, P. Subramaniam, M.J. Taylor, J. Uusitalo, J.J. Valiente-Dobon

Research output: Contribution to journalLetter

Abstract

Lifetimes of the first excited 2+ and 4+ states in the extremely neutron-deficient nuclide 172Pt have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B(E2:4+1→2+1)/B(E2:2+1→0+gs)=0.55(19) was found, similar to a handful of other such anomalous cases observed in the entire Segré chart. The observation adds to a cluster of a few extremely neutron-deficient nuclides of the heavy transition metals with neutron numbers N≈90–94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B(E2:4+1→2+1)/B(E2:2+1→0+gs) ratios observed in these cases. Such low values cannot, e.g., be explained within the framework of the geometrical collective model or by algebraic approaches within the interacting boson model framework. It is proposed that the group of B(E2:4+1→2+1)/B(E2:2+1→0+gs) ratios in the extremely neutron-deficient even-even W, Os, and Pt nuclei around neutron numbers N≈90–94 reveal a quantum phase transition from a seniority-conserving structure to a collective regime as a function of neutron number. Although a system governed by seniority symmetry is the only theoretical framework for which such an effect may naturally occur, the phenomenon is highly unexpected for these nuclei that are not situated near closed shells.
Original languageEnglish
Article number022502
Number of pages6
JournalPhysical Review Letters
Volume121
Issue number2
DOIs
Publication statusPublished - 10 Jul 2018
Externally publishedYes

Fingerprint

angular momentum
quadrupoles
neutrons
life (durability)
excitation
nuclides
nuclei
charts
heavy metals
marking
bosons
transition metals
shift
symmetry
decay

Keywords

  • electromagnetic transitions
  • lifetimes and widths
  • nuclear fusion

Cite this

Cederwall, B., Doncel, M., Aktaş, Ö., Ertoprak, A., Liotta, R., Qi, C., ... Valiente-Dobon, J. J. (2018). Lifetime measurements of excited states in 172Pt and the variation of quadrupole transition strength with angular momentum. Physical Review Letters, 121(2), [022502]. https://doi.org/10.1103/PhysRevLett.121.022502
Cederwall, B. ; Doncel, M. ; Aktaş, Ö. ; Ertoprak, A. ; Liotta, R. ; Qi, C. ; Grahn, T. ; Cullen, D.M. ; Nara Singh, B.S. ; Hodge, D. ; Giles, M. ; Stolze, S. ; Badran, H. ; Braunroth, T. ; Calverley, T. ; Cox, D.M. ; Fang, Y.D. ; Greenlees, P.T. ; Hilton, J. ; Ideguchi, E. ; Julin, R. ; Juutinen, S. ; Kumar Raju, M. ; Li, H. ; Liu, H. ; Matta, S. ; Modamio, V. ; Pakarinen, J. ; Papadakis, P. ; Partanen, J. ; Petrache, C.M. ; Rahkila, P. ; Ruotslainen, P. ; Sandzelius, M. ; Saren, J. ; Scholey, C. ; Sorri, J. ; Subramaniam, P. ; Taylor, M.J. ; Uusitalo, J. ; Valiente-Dobon, J.J. / Lifetime measurements of excited states in 172Pt and the variation of quadrupole transition strength with angular momentum. In: Physical Review Letters. 2018 ; Vol. 121, No. 2.
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title = "Lifetime measurements of excited states in 172Pt and the variation of quadrupole transition strength with angular momentum",
abstract = "Lifetimes of the first excited 2+ and 4+ states in the extremely neutron-deficient nuclide 172Pt have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B(E2:4+1→2+1)/B(E2:2+1→0+gs)=0.55(19) was found, similar to a handful of other such anomalous cases observed in the entire Segr{\'e} chart. The observation adds to a cluster of a few extremely neutron-deficient nuclides of the heavy transition metals with neutron numbers N≈90–94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B(E2:4+1→2+1)/B(E2:2+1→0+gs) ratios observed in these cases. Such low values cannot, e.g., be explained within the framework of the geometrical collective model or by algebraic approaches within the interacting boson model framework. It is proposed that the group of B(E2:4+1→2+1)/B(E2:2+1→0+gs) ratios in the extremely neutron-deficient even-even W, Os, and Pt nuclei around neutron numbers N≈90–94 reveal a quantum phase transition from a seniority-conserving structure to a collective regime as a function of neutron number. Although a system governed by seniority symmetry is the only theoretical framework for which such an effect may naturally occur, the phenomenon is highly unexpected for these nuclei that are not situated near closed shells.",
keywords = "electromagnetic transitions, lifetimes and widths, nuclear fusion",
author = "B. Cederwall and M. Doncel and {\"O}. Aktaş and A. Ertoprak and R. Liotta and C. Qi and T. Grahn and D.M. Cullen and {Nara Singh}, B.S. and D. Hodge and M. Giles and S. Stolze and H. Badran and T. Braunroth and T. Calverley and D.M. Cox and Y.D. Fang and P.T. Greenlees and J. Hilton and E. Ideguchi and R. Julin and S. Juutinen and {Kumar Raju}, M. and H. Li and H. Liu and S. Matta and V. Modamio and J. Pakarinen and P. Papadakis and J. Partanen and C.M. Petrache and P. Rahkila and P. Ruotslainen and M. Sandzelius and J. Saren and C. Scholey and J. Sorri and P. Subramaniam and M.J. Taylor and J. Uusitalo and J.J. Valiente-Dobon",
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language = "English",
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journal = "Physical Review Letters",
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Cederwall, B, Doncel, M, Aktaş, Ö, Ertoprak, A, Liotta, R, Qi, C, Grahn, T, Cullen, DM, Nara Singh, BS, Hodge, D, Giles, M, Stolze, S, Badran, H, Braunroth, T, Calverley, T, Cox, DM, Fang, YD, Greenlees, PT, Hilton, J, Ideguchi, E, Julin, R, Juutinen, S, Kumar Raju, M, Li, H, Liu, H, Matta, S, Modamio, V, Pakarinen, J, Papadakis, P, Partanen, J, Petrache, CM, Rahkila, P, Ruotslainen, P, Sandzelius, M, Saren, J, Scholey, C, Sorri, J, Subramaniam, P, Taylor, MJ, Uusitalo, J & Valiente-Dobon, JJ 2018, 'Lifetime measurements of excited states in 172Pt and the variation of quadrupole transition strength with angular momentum' Physical Review Letters, vol. 121, no. 2, 022502. https://doi.org/10.1103/PhysRevLett.121.022502

Lifetime measurements of excited states in 172Pt and the variation of quadrupole transition strength with angular momentum. / Cederwall, B.; Doncel, M.; Aktaş, Ö.; Ertoprak, A.; Liotta, R.; Qi, C.; Grahn, T.; Cullen, D.M.; Nara Singh, B.S.; Hodge, D.; Giles, M.; Stolze, S.; Badran, H.; Braunroth, T.; Calverley, T.; Cox, D.M.; Fang, Y.D.; Greenlees, P.T.; Hilton, J.; Ideguchi, E.; Julin, R.; Juutinen, S.; Kumar Raju, M.; Li, H.; Liu, H.; Matta, S.; Modamio, V.; Pakarinen, J.; Papadakis, P.; Partanen, J.; Petrache, C.M.; Rahkila, P.; Ruotslainen, P.; Sandzelius, M.; Saren, J.; Scholey, C.; Sorri, J.; Subramaniam, P.; Taylor, M.J.; Uusitalo, J.; Valiente-Dobon, J.J.

In: Physical Review Letters, Vol. 121, No. 2, 022502, 10.07.2018.

Research output: Contribution to journalLetter

TY - JOUR

T1 - Lifetime measurements of excited states in 172Pt and the variation of quadrupole transition strength with angular momentum

AU - Cederwall, B.

AU - Doncel, M.

AU - Aktaş, Ö.

AU - Ertoprak, A.

AU - Liotta, R.

AU - Qi, C.

AU - Grahn, T.

AU - Cullen, D.M.

AU - Nara Singh, B.S.

AU - Hodge, D.

AU - Giles, M.

AU - Stolze, S.

AU - Badran, H.

AU - Braunroth, T.

AU - Calverley, T.

AU - Cox, D.M.

AU - Fang, Y.D.

AU - Greenlees, P.T.

AU - Hilton, J.

AU - Ideguchi, E.

AU - Julin, R.

AU - Juutinen, S.

AU - Kumar Raju, M.

AU - Li, H.

AU - Liu, H.

AU - Matta, S.

AU - Modamio, V.

AU - Pakarinen, J.

AU - Papadakis, P.

AU - Partanen, J.

AU - Petrache, C.M.

AU - Rahkila, P.

AU - Ruotslainen, P.

AU - Sandzelius, M.

AU - Saren, J.

AU - Scholey, C.

AU - Sorri, J.

AU - Subramaniam, P.

AU - Taylor, M.J.

AU - Uusitalo, J.

AU - Valiente-Dobon, J.J.

PY - 2018/7/10

Y1 - 2018/7/10

N2 - Lifetimes of the first excited 2+ and 4+ states in the extremely neutron-deficient nuclide 172Pt have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B(E2:4+1→2+1)/B(E2:2+1→0+gs)=0.55(19) was found, similar to a handful of other such anomalous cases observed in the entire Segré chart. The observation adds to a cluster of a few extremely neutron-deficient nuclides of the heavy transition metals with neutron numbers N≈90–94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B(E2:4+1→2+1)/B(E2:2+1→0+gs) ratios observed in these cases. Such low values cannot, e.g., be explained within the framework of the geometrical collective model or by algebraic approaches within the interacting boson model framework. It is proposed that the group of B(E2:4+1→2+1)/B(E2:2+1→0+gs) ratios in the extremely neutron-deficient even-even W, Os, and Pt nuclei around neutron numbers N≈90–94 reveal a quantum phase transition from a seniority-conserving structure to a collective regime as a function of neutron number. Although a system governed by seniority symmetry is the only theoretical framework for which such an effect may naturally occur, the phenomenon is highly unexpected for these nuclei that are not situated near closed shells.

AB - Lifetimes of the first excited 2+ and 4+ states in the extremely neutron-deficient nuclide 172Pt have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B(E2:4+1→2+1)/B(E2:2+1→0+gs)=0.55(19) was found, similar to a handful of other such anomalous cases observed in the entire Segré chart. The observation adds to a cluster of a few extremely neutron-deficient nuclides of the heavy transition metals with neutron numbers N≈90–94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B(E2:4+1→2+1)/B(E2:2+1→0+gs) ratios observed in these cases. Such low values cannot, e.g., be explained within the framework of the geometrical collective model or by algebraic approaches within the interacting boson model framework. It is proposed that the group of B(E2:4+1→2+1)/B(E2:2+1→0+gs) ratios in the extremely neutron-deficient even-even W, Os, and Pt nuclei around neutron numbers N≈90–94 reveal a quantum phase transition from a seniority-conserving structure to a collective regime as a function of neutron number. Although a system governed by seniority symmetry is the only theoretical framework for which such an effect may naturally occur, the phenomenon is highly unexpected for these nuclei that are not situated near closed shells.

KW - electromagnetic transitions

KW - lifetimes and widths

KW - nuclear fusion

U2 - 10.1103/PhysRevLett.121.022502

DO - 10.1103/PhysRevLett.121.022502

M3 - Letter

VL - 121

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 2

M1 - 022502

ER -