Nuclear Theory·nucl-th

Thursday·August 21, 2025

4 papers—2 primary·2 cross-listed

01
[Submitted on 19 Aug 2025]
Structure of the doubly magic nuclei $^{208}$ Pb and $^{266}$ Pb from ab initio computations
Francesca Bonaiti🇺🇸 · Gaute Hagen🇺🇸 · Thomas Papenbrock🇺🇸
Theoretical studies indicate that the superheavy neutron-rich nucleus $_{82}^{266}$ Pb $_{184}$ is doubly magic and at the neutron drip line. While its density distributions and single-particle energies have been computed, the structure of this nucleus is yet unknown. We perform ab initio computations of $^{266}$ Pb using an interaction from an effective field theory of quantum chromodynamics tuned only on properties of nuclei with $A \leq 4$ . We validate our theoretical framework by computing the first $2^{+}$ and $3^{-}$ excited states of $^{208}$ Pb, finding agreement with experimental data. We confirm that $^{266}$ Pb is doubly magic and show that its $3^{-}$ state, located below the $2^{+}$ state, exhibits an excitation gap of 2.6 MeV with respect to the ground state. Our calculations also suggest that this nucleus is at the neutron drip line.
Comments:
5 pages, 5 figures, corrected typos, updated data reference
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2508.14217 [pdf]
29 citations
02
[Submitted on 20 Aug 2025]
Fragmentation of the IAR along the chains $N = 50$ and $Z = 50$
David Durel🇫🇷 · Sophie Péru🇫🇷 · Marco Martini🇫🇷
We study Isobaric Analog Resonances in even-even nuclei along the $N = 50$ isotonic chain. First, Hartree-Fock-Bogoliubov calculations, using the Gogny D1M effective interaction, have been performed to provide energies and occupation probabilities of nucleon orbitals. The Isobaric Analog Resonances are calculated with the charge exchange QRPA approach on top of then HFB calculations. Fermi transition mechanism is interpreted with the existence of collective modes in the final nucleus. The fragmentation of the Fermi Strength results from the fractional occupation of nucleon shells, a direct consequence of nuclear pairing. The theoretical Fermi transition probabilities along the isotopic chain $Z = 50$ are also analyzed and confirm our conclusions.
Comments:
Due to a wrong sign of paring terms in the equations and code, early results are obsolete. The fragmentation of IAR now seems less pronounced. Work is in progress to analyze the contribution of each term of the Gogny interaction in order to merge all modes into a single resonance
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2508.14643 [pdf]
0 citations

Affiliations

first authorsco-authorsvia INSPIRE

Structure of the doubly magic nuclei 208Pb and 266Pb from ab initio computations

Fragmentation of the IAR along the chains N=50 and Z=50

Affiliations

Structure of the doubly magic nuclei $^{208}$ Pb and $^{266}$ Pb from ab initio computations

Fragmentation of the IAR along the chains $N = 50$ and $Z = 50$