Shape coexistence in 94Zr from a model-independent analysis

N. Marchini; M. Rocchini; M. Zielińska; A. Nannini; D.T. Doherty; N. Gavrielrov; P.E. Garrett; K. Hadyńska-Klęk; A. Goasduff; D. Testov; S.D. Bakes; D. Bazzacco; G. Benzoni; T. Berry; D. Brugnara; F. Camera; W.N. Catford; M. Chiari; F. Galtarossa; N. Gelli; A. Gottardo; A. Gozzelino; A. Illana; J. Keatings; D. Mengoni; L. Morrison; D. R. Napoli; M. Ottanelli; P. Ottanelli; G. Pasqualato; F. Recchia; S. Riccetto; M. Scheck; M. Siciliano; J.J. Valiente-Dobón; I. Zanon

doi:10.1016/j.physletb.2026.140668

Shape coexistence in ⁹⁴Zr from a model-independent analysis

N. Marchini^*
, M. Rocchini
, M. Zielińska
, A. Nannini
, D.T. Doherty
, N. Gavrielrov^*
, P.E. Garrett
, K. Hadyńska-Klęk
, A. Goasduff
, D. Testov
, S.D. Bakes
, D. Bazzacco
, G. Benzoni
, T. Berry
, D. Brugnara
, F. Camera
, W.N. Catford
, M. Chiari
, F. Galtarossa
, N. Gelli

A. Gottardo, A. Gozzelino, A. Illana, J. Keatings, D. Mengoni, L. Morrison, D. R. Napoli, M. Ottanelli, P. Ottanelli, G. Pasqualato, F. Recchia, S. Riccetto, M. Scheck, M. Siciliano, J.J. Valiente-Dobón, I. Zanon

^*Corresponding author for this work

Research output: Contribution to journal › Letter › peer-review

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Abstract

Low-lying states of ⁹⁴Zr were investigated via low-energy multi-step Coulomb excitation. From the measured γ-ray yields, 16 reduced E2 transition probabilities between low-spin states were determined, together with the spectroscopic quadrupole moments of the 2⁺_1,2 states. Based on this information, for the first time in the Zr isotopic chain, the shapes of the 0⁺_1,2 states including their deformation softness were inferred in a model-independent way using the quadrupole sum rules approach. The ground state of ⁹⁴Zr possesses a rather diffuse shape associated with a spherical configuration, while the 0⁺₂ state is triaxial tending towards oblate and more strongly deformed. The observed features of shape coexistence in ⁹⁴Zr are consistent with both Monte-Carlo shell-model predictions and IBM-CM calculations, and provide model-independent constraints on the shape character assigned in the IBM-CM to the intruder configuration in ^92–96Zr.

Original language	English
Article number	140668
Number of pages	7
Journal	Physics Letters B
Volume	879
Early online date	20 Jun 2026
DOIs	https://doi.org/10.1016/j.physletb.2026.140668
Publication status	E-pub ahead of print - 20 Jun 2026

Keywords

low-energy Coulomb excitation
shape coexistence
nuclear structure

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10.1016/j.physletb.2026.140668Licence: CC BY 4.0

2026 06 18 Marchini et al Shape finalFinal published version, 1.7 MBLicence: CC BY 4.0

Cite this

Marchini, N., Rocchini, M., Zielińska, M., Nannini, A., Doherty, D. T., Gavrielrov, N., Garrett, P. E., Hadyńska-Klęk, K., Goasduff, A., Testov, D., Bakes, S. D., Bazzacco, D., Benzoni, G., Berry, T., Brugnara, D., Camera, F., Catford, W. N., Chiari, M., Galtarossa, F., ... Zanon, I. (2026). Shape coexistence in ⁹⁴Zr from a model-independent analysis. Physics Letters B, 879, Article 140668. Advance online publication. https://doi.org/10.1016/j.physletb.2026.140668

@article{c60b4775fe4f4c45ac99da427266b5bb,

title = "Shape coexistence in 94Zr from a model-independent analysis",

abstract = "Low-lying states of 94Zr were investigated via low-energy multi-step Coulomb excitation. From the measured γ-ray yields, 16 reduced E2 transition probabilities between low-spin states were determined, together with the spectroscopic quadrupole moments of the 2+1,2 states. Based on this information, for the first time in the Zr isotopic chain, the shapes of the 0+1,2 states including their deformation softness were inferred in a model-independent way using the quadrupole sum rules approach. The ground state of 94Zr possesses a rather diffuse shape associated with a spherical configuration, while the 0+2 state is triaxial tending towards oblate and more strongly deformed. The observed features of shape coexistence in 94Zr are consistent with both Monte-Carlo shell-model predictions and IBM-CM calculations, and provide model-independent constraints on the shape character assigned in the IBM-CM to the intruder configuration in 92–96Zr.",

keywords = "low-energy Coulomb excitation, shape coexistence, nuclear structure",

author = "N. Marchini and M. Rocchini and M. Zieli{\'n}ska and A. Nannini and D.T. Doherty and N. Gavrielrov and P.E. Garrett and K. Hady{\'n}ska-Kl{\c e}k and A. Goasduff and D. Testov and S.D. Bakes and D. Bazzacco and G. Benzoni and T. Berry and D. Brugnara and F. Camera and W.N. Catford and M. Chiari and F. Galtarossa and N. Gelli and A. Gottardo and A. Gozzelino and A. Illana and J. Keatings and D. Mengoni and L. Morrison and Napoli, \{D. R.\} and M. Ottanelli and P. Ottanelli and G. Pasqualato and F. Recchia and S. Riccetto and M. Scheck and M. Siciliano and J.J. Valiente-Dob{\'o}n and I. Zanon",

year = "2026",

month = jun,

day = "20",

doi = "10.1016/j.physletb.2026.140668",

language = "English",

volume = "879",

journal = "Physics Letters B",

issn = "0370-2693",

publisher = "Elsevier B.V.",

}

Marchini, N, Rocchini, M, Zielińska, M, Nannini, A, Doherty, DT, Gavrielrov, N, Garrett, PE, Hadyńska-Klęk, K, Goasduff, A, Testov, D, Bakes, SD, Bazzacco, D, Benzoni, G, Berry, T, Brugnara, D, Camera, F, Catford, WN, Chiari, M, Galtarossa, F, Gelli, N, Gottardo, A, Gozzelino, A, Illana, A, Keatings, J, Mengoni, D, Morrison, L, Napoli, DR, Ottanelli, M, Ottanelli, P, Pasqualato, G, Recchia, F, Riccetto, S, Scheck, M, Siciliano, M, Valiente-Dobón, JJ & Zanon, I 2026, 'Shape coexistence in ⁹⁴Zr from a model-independent analysis', Physics Letters B, vol. 879, 140668. https://doi.org/10.1016/j.physletb.2026.140668

TY - JOUR

T1 - Shape coexistence in 94Zr from a model-independent analysis

AU - Marchini, N.

AU - Rocchini, M.

AU - Zielińska, M.

AU - Nannini, A.

AU - Doherty, D.T.

AU - Gavrielrov, N.

AU - Garrett, P.E.

AU - Hadyńska-Klęk, K.

AU - Goasduff, A.

AU - Testov, D.

AU - Bakes, S.D.

AU - Bazzacco, D.

AU - Benzoni, G.

AU - Berry, T.

AU - Brugnara, D.

AU - Camera, F.

AU - Catford, W.N.

AU - Chiari, M.

AU - Galtarossa, F.

AU - Gelli, N.

AU - Gottardo, A.

AU - Gozzelino, A.

AU - Illana, A.

AU - Keatings, J.

AU - Mengoni, D.

AU - Morrison, L.

AU - Napoli, D. R.

AU - Ottanelli, M.

AU - Ottanelli, P.

AU - Pasqualato, G.

AU - Recchia, F.

AU - Riccetto, S.

AU - Scheck, M.

AU - Siciliano, M.

AU - Valiente-Dobón, J.J.

AU - Zanon, I.

PY - 2026/6/20

Y1 - 2026/6/20

N2 - Low-lying states of 94Zr were investigated via low-energy multi-step Coulomb excitation. From the measured γ-ray yields, 16 reduced E2 transition probabilities between low-spin states were determined, together with the spectroscopic quadrupole moments of the 2+1,2 states. Based on this information, for the first time in the Zr isotopic chain, the shapes of the 0+1,2 states including their deformation softness were inferred in a model-independent way using the quadrupole sum rules approach. The ground state of 94Zr possesses a rather diffuse shape associated with a spherical configuration, while the 0+2 state is triaxial tending towards oblate and more strongly deformed. The observed features of shape coexistence in 94Zr are consistent with both Monte-Carlo shell-model predictions and IBM-CM calculations, and provide model-independent constraints on the shape character assigned in the IBM-CM to the intruder configuration in 92–96Zr.

AB - Low-lying states of 94Zr were investigated via low-energy multi-step Coulomb excitation. From the measured γ-ray yields, 16 reduced E2 transition probabilities between low-spin states were determined, together with the spectroscopic quadrupole moments of the 2+1,2 states. Based on this information, for the first time in the Zr isotopic chain, the shapes of the 0+1,2 states including their deformation softness were inferred in a model-independent way using the quadrupole sum rules approach. The ground state of 94Zr possesses a rather diffuse shape associated with a spherical configuration, while the 0+2 state is triaxial tending towards oblate and more strongly deformed. The observed features of shape coexistence in 94Zr are consistent with both Monte-Carlo shell-model predictions and IBM-CM calculations, and provide model-independent constraints on the shape character assigned in the IBM-CM to the intruder configuration in 92–96Zr.

KW - low-energy Coulomb excitation

KW - shape coexistence

KW - nuclear structure

U2 - 10.1016/j.physletb.2026.140668

DO - 10.1016/j.physletb.2026.140668

M3 - Letter

SN - 0370-2693

VL - 879

JO - Physics Letters B

JF - Physics Letters B

M1 - 140668

ER -