Peer-reviewedCC BY 4.0Phys.Lett.B
First experimental isotopic mapping of the fission “γ-bump” and its connection to the Pygmy dipole resonance
Abstract
Nuclear fission produces two excited fragments which fast fly apart. Their properties at scission depend on the dynamics of fission, and rule their return to equilibrium. The present work addresses the excess of γ-rays with energies between 3 and 8 MeV emitted during the fragment de-excitation, revealed in the 80’s but hitherto not fully understood. Combining a state-of-the-art heavy-ion spectrometer and an array of novel scintillators, the island of existence of the so-called “γ-bump” is delineated, and its topography mapped as a function of fragment emitter proton and neutron numbers for the first time. Its connection to the Pygmy Dipole Resonance is discussed by means of dedicated fission calculations employing microscopic nuclear level densities and γ strength functions. Besides giving insight into the post-scission dynamics of the fragments, the present finding would make fission a new probe of soft dipole modes, complementary to the conventional approaches.
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BibTeX
@article{kumar2026first,
title = {{First experimental isotopic mapping of the fission “$\gamma$-bump” and its connection to the Pygmy dipole resonance}},
author = {N Kumar and C Schmitt and M Ciemala and A Maj and A Lemasson and D Ramos and M Rejmund and S Brambilla and Y Cho and E Clément and O Dorvaux and J Dudouet and G De. France and A Goasduff and B Jacquot and S Kihel and M Lewitowicz and O Litaize and I Matea and S Péru and D.S Ahn and A.N Andreyev and P Bednarczyk and C Boiano and C Borcea and A Bracco and M Caamano and S Calinescu and D Curien and F Didierjean and G Duchn̂e and S Erturk and M Filliger and M Forge and B Fornal and B Gall and I Harca and D.G Jenkins and D.T Kattikat Melcom and Y.H Kim and M Kmiecik and S Leoni and K Mazurek and V Nanal and A Navin and A Oberstedt and S Oberstedt and C Petrone and Julien Piot and B Sowicki and M Stanoiu and L Stuttgé and A Utepov and M Ziȩbliński},
journal = {Phys.Lett.B},
year = {2026},
month = sep,
doi = {10.1016/j.physletb.2026.140506},
url = {https://hal.science/hal-05686541v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - First experimental isotopic mapping of the fission “γ-bump” and its connection to the Pygmy dipole resonance
AU - N Kumar
AU - C Schmitt
AU - M Ciemala
AU - A Maj
AU - A Lemasson
AU - D Ramos
AU - M Rejmund
AU - S Brambilla
AU - Y Cho
AU - E Clément
AU - O Dorvaux
AU - J Dudouet
AU - G De. France
AU - A Goasduff
AU - B Jacquot
AU - S Kihel
AU - M Lewitowicz
AU - O Litaize
AU - I Matea
AU - S Péru
AU - D.S Ahn
AU - A.N Andreyev
AU - P Bednarczyk
AU - C Boiano
AU - C Borcea
AU - A Bracco
AU - M Caamano
AU - S Calinescu
AU - D Curien
AU - F Didierjean
AU - G Duchn̂e
AU - S Erturk
AU - M Filliger
AU - M Forge
AU - B Fornal
AU - B Gall
AU - I Harca
AU - D.G Jenkins
AU - D.T Kattikat Melcom
AU - Y.H Kim
AU - M Kmiecik
AU - S Leoni
AU - K Mazurek
AU - V Nanal
AU - A Navin
AU - A Oberstedt
AU - S Oberstedt
AU - C Petrone
AU - Julien Piot
AU - B Sowicki
AU - M Stanoiu
AU - L Stuttgé
AU - A Utepov
AU - M Ziȩbliński
PY - 2026
DA - 2026/09/25
JO - Phys.Lett.B
DO - 10.1016/j.physletb.2026.140506
UR - https://hal.science/hal-05686541v1
AB - Nuclear fission produces two excited fragments which fast fly apart. Their properties at scission depend on the dynamics of fission, and rule their return to equilibrium. The present work addresses the excess of γ-rays with energies between 3 and 8 MeV emitted during the fragment de-excitation, revealed in the 80’s but hitherto not fully understood. Combining a state-of-the-art heavy-ion spectrometer and an array of novel scintillators, the island of existence of the so-called “γ-bump” is delineated, and its topography mapped as a function of fragment emitter proton and neutron numbers for the first time. Its connection to the Pygmy Dipole Resonance is discussed by means of dedicated fission calculations employing microscopic nuclear level densities and γ strength functions. Besides giving insight into the post-scission dynamics of the fragments, the present finding would make fission a new probe of soft dipole modes, complementary to the conventional approaches.
ER -