First observation of the fine structure of the Pygmy Dipole Resonance in a nucleus away from stability via the β^- decay of ⁹²Rb to ⁹²Sr

@misc{spagnoletti2026first,
  title = {{First observation of the fine structure of the Pygmy Dipole Resonance in a nucleus away from stability via the $β^-$ decay of $^92$Rb to $^92$Sr}},
  author = {P Spagnoletti and M Ramalho and S Tahtela and E Kauppinen and J Suhonen and C Andreoiu and M Scheck and V Vedia and Z Ahmed and D Annen and G.C Ball and G Benzoni and S.S Bhattacharjee and H Bidaman and V Bildstein and S Buck and R Caballero-Folch and R.J Coleman and S Devinyak and I Dillmann and I Djianto and F.H Garcia and A.B Garnsworthy and P.E Garrett and B Greaves and C.J Griffin and G.F Grinyer and E.G Fuakye and G Hackman and D Hymers and D Kalaydjieva and R Kanungo and K Kapoor and E Kasanda and W Korten and N Marchini and K Mashtakov and A Nannini and K Ortner and B Olaizola and C Natzke and C.M Petrache and M Polettini and A Radich and M Rocchini and N Saei and M Satrazani and M Siciliano and M Singh and C.E Svensson and D.A Torres and R Umashankar and E Wadge and T Zidar and M Zielinska},
  howpublished = {HAL},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.21520},
  eprint = {2609.21520},
  archivePrefix = {arXiv},
  url = {https://hal.science/hal-05770485v1},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - First observation of the fine structure of the Pygmy Dipole Resonance in a nucleus away from stability via the β^- decay of ^92Rb to ^92Sr
AU  - P Spagnoletti
AU  - M Ramalho
AU  - S Tahtela
AU  - E Kauppinen
AU  - J Suhonen
AU  - C Andreoiu
AU  - M Scheck
AU  - V Vedia
AU  - Z Ahmed
AU  - D Annen
AU  - G.C Ball
AU  - G Benzoni
AU  - S.S Bhattacharjee
AU  - H Bidaman
AU  - V Bildstein
AU  - S Buck
AU  - R Caballero-Folch
AU  - R.J Coleman
AU  - S Devinyak
AU  - I Dillmann
AU  - I Djianto
AU  - F.H Garcia
AU  - A.B Garnsworthy
AU  - P.E Garrett
AU  - B Greaves
AU  - C.J Griffin
AU  - G.F Grinyer
AU  - E.G Fuakye
AU  - G Hackman
AU  - D Hymers
AU  - D Kalaydjieva
AU  - R Kanungo
AU  - K Kapoor
AU  - E Kasanda
AU  - W Korten
AU  - N Marchini
AU  - K Mashtakov
AU  - A Nannini
AU  - K Ortner
AU  - B Olaizola
AU  - C Natzke
AU  - C.M Petrache
AU  - M Polettini
AU  - A Radich
AU  - M Rocchini
AU  - N Saei
AU  - M Satrazani
AU  - M Siciliano
AU  - M Singh
AU  - C.E Svensson
AU  - D.A Torres
AU  - R Umashankar
AU  - E Wadge
AU  - T Zidar
AU  - M Zielinska
PY  - 2026
DA  - 2026/09/18
PB  - HAL
DO  - 10.48550/arxiv.2609.21520
UR  - https://hal.science/hal-05770485v1
AB  - A comprehensive γ-ray spectroscopy study of excited states in ^92Sr populated via β^- decay of ^92Rb (J^π=0^-, Q_β=8095(6)~keV) was performed with the GRIFFIN spectrometer at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility at TRIUMF. The high γ-ray efficiency of the GRIFFIN spectrometer combined with the intense rubidium beams produced allowed for 864 γ-ray transitions to be placed in the level scheme with 190 excited levels populated, most of them identified for the first time. The excitation energies of low-spin states in ^92Sr are well reproduced by large-scale Shell Model calculations up to 5~MeV. The β-feeding intensities are in very good agreement with results from a recent study employing Modular Total Absorption Spectroscopy, indicating a significant suppression of the Pandemonium effect. The experimental picture reveals the energy level dependence of log~ft values in unprecedented detail. These log~ft values are well reproduced by Multiple-Commutator Model calculations that identify the features in the excited levels' wavefunctions that enable the population of high-lying levels with a low effective Q-value that belong to the Pygmy Dipole Resonance.
ER  -