Nuclear Theory·nucl-th

Thursday·January 15, 2026

7 papers—5 primary·2 cross-listed

01
[Submitted on 13 Jan 2026]
Comment on "Spin-trap isomers in deformed, odd-odd nuclei in the light rare-earth region near N = 98"
N. Susshma · S. Deepa · K. Vijay Sai · R. Gowrishankar
Mass spectrometry studies of odd-odd light rare-earth nuclei by Orford et al. [Phys. Rev. C 102, 011303(R) (2020)] suggested the existence of new isomers in the neutron rich isotopes $^{162}$ Tb and $^{164}$ Tb. More recently, Stryjczyk et al. [Phys. Rev. C 111, 049801 (2025)] commented on the former, citing inconsistencies between the available experimental data and the proposed presence of an isomer in $^{162}$ Tb. To further examine the possibility of isomeric states in $^{162, 164}$ Tb, we employed the well-tested empirical Two Quasiparticle Rotor Model to construct their low-lying level structure. The resulting level schemes support the potential existence of low-lying isomeric states in both isotopes and we propose their corresponding spin-parities, orbital configurations, and excitation energies.
Comments:
Comment on https://link.aps.org/doi/10.1103/PhysRevC.102.011303
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.08897 [pdf]
0 citations
02
[Submitted on 14 Jan 2026]
Comments on Baryon Transition Form Factors
Christoph Hanhart · Maxim Mai · Ulf-G. Meißner · Deborah Rönchen
We discuss in rather general terms the properties of space-like baryon transition form factors. In particular, we argue why these are necessarily complex-valued, what can be deduced from the respective phase motion and why dealing with real valued transition form factors in general leads to misleading results. For illustration the transition form factors for the Roper resonance as derived in the Jülich-Bonn-Washington framework are discussed.
Comments:
Prepared for the occasion of David Roper's 90 $^{th}$ birthday
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2601.09307 [pdf]
Acta Phys.Polon.B(2026)·0 citations
03
[Submitted on 14 Jan 2026]
Shell and cluster structures in $^{20}$ Ne in the variation of multiple bases of the antisymmetrized molecular dynamics
Takayuki Myo · Mengjiao Lyu · Qing Zhao · Masahiro Isaka · Niu Wan · Hiroki Takemoto · Hisashi Horiuchi · Akinobu Doté
We investigate the structures of $^{20}$ Ne in the variation of the multiple bases of the antisymmetrized molecular dynamics (AMD). In this method, the multiple AMD bases are superposed and optimized simultaneously in the total-energy variation. This scheme is beneficial for describing the various configurations in $^{20}$ Ne. In the results, we confirm the shell and cluster structures in the $K^{π} = 0_{1 - 4}^{+}$ bands, such as the deformed states in the $K^{π} = 0_{1, 4}^{+}$ bands with the $α$ cluster development, and the spherical shell-like states in the $K^{π} = 0_{2}^{+}$ band, the latter of which is difficult to describe in the previous AMD calculations imposing the quadrupole deformation. We evaluate the monopole and quadrupole transitions in these states. The negative parity states of $^{20}$ Ne with $K^{π} = 0^{-}$ and $2^{-}$ are discussed in relation to the shell and cluster structures. As a result, six kinds of the $K^{π}$ bands in $^{20}$ Ne are described comprehensively in the microscopic framework of nuclei.
Comments:
12 pages, 10 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2601.09424 [pdf]
PRC(2025)·2 citations
04
[Submitted on 14 Jan 2026]
Probing the two-quasiparticle $K^{π} = 8^{+}$ isomeric structure and enhanced stability in the proton drip-line nuclei
Zhen-Zhen Zhang · Hua-Lei Wang · Kui Xiao · Min-Liang Liu
Stimulated by recent experimental discoveries [{Phys. Lett. B \textbf{847}, 138310 (2023)} and {Phys. Rev. Lett. \textbf{132}, 072502 (2024)}], two-quasiparticle $K^{π} = 8^{+}$ isomeric structure (related to the neutron $h_{9/2}$ and $f_{7/2}$ orbitals) in $_{76}^{160}$ Os $_{84}$ that lies at the two-proton drip line has been studied by means of the configuration-constrained potential-energy-surface calculations. Calculated results indicate that, for such an isomer, the excitation energy can be well reproduced and its oblate shape can be enhanced by the polarization effects of the two high- $K$ orbits. Comparing with experimental data, two sets of the widely used Woods-Saxon parameters, especially, the spin-orbit coupling one, are evaluated and argued. It is found that, considering the uncertainty of the spin-orbit coupling strength, the energy crossing or inversion of the $h_{9/2}$ and $f_{7/2}$ neutrons can occur, which may lead to three kinds of different evolution-trends of two-quasiparticle excitation energies with the changing quadrupole deformation $β_{2}$ . With decreasing spin-orbit coupling interaction, the structure of the $K^{π} = 8^{+}$ isomeric state will evolute from $ν h_{9/2} f_{7/2}$ ( $ν 9/ 2^{-} [505] \otimes 7/ 2^{-} [503]$ ) to the mixing of $ν h_{9/2} f_{7/2}$ and $ν h_{9/2}^{2}$ ( $ν 9/ 2^{-} [505] \otimes 7/ 2^{-} [514]$ ) to $ν h_{9/2}^{2}$ , indicating that its structural probes is still of interest and an arbitrary assignment may be risky. The related theoretical calculations and experimental evidences e.g., the transition properties, are desirable. In addition, similar to that in superheavy nuclei, it is suggested that the stability inversion between high- $K$ isomeric states and ground states might occur in this proton drip-line mass region, e.g., in the hitherto unknown nucleus $_{78}^{162}$ Pt $_{84}$ .
Comments:
12 pages,6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.09526 [pdf]
Nucl.Sci.Tech.(2026)·0 citations
05
[Submitted on 14 Jan 2026]
Ab initio charge form factors and radii of light isoscalar nuclei: Role of the two-body charge density
Xiang-Xiang Sun · Vadim Baru · Arseniy A. Filin · Evgeny Epelbaum · Hermann Krebs · Ulf-G. Meißner · Andreas Nogga
We make \textit{ab initio} predictions of charge form factors (FFs) and radii for the isoscalar nuclei $^{6}$ Li and $^{8}$ Be using the Jacobi-coordinate No-Core Shell Model. The calculations employ chiral semilocal momentum-space regularized two- and three-nucleon interactions, together with consistently regularized one- and two-nucleon electromagnetic charge operators. With the short-range charge density fixed to the $^{4}$ He charge radius, the predicted FFs and the $^{6}$ Li radius show good agreement with available experimental data. We find that two-nucleon charge density contributions are essential for describing the FFs, particularly at intermediate and large momentum transfers. Although their influence on the charge radii is limited, these contributions remain crucial for attaining accurate predictions. The present results highlight the importance of two-nucleon charge operators in addressing the long-standing underestimation of nuclear charge radii in \textit{ab initio} calculations based on modern chiral interactions.
Comments:
6 pages, 2 figures, 1 table, additional supplement (5 pages, 5 figures)
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2601.09614 [pdf]
3 citations

Affiliations

first authorsco-authorsvia INSPIRE

Comment on "Spin-trap isomers in deformed, odd-odd nuclei in the light rare-earth region near N = 98"

Comments on Baryon Transition Form Factors

Shell and cluster structures in 20Ne in the variation of multiple bases of the antisymmetrized molecular dynamics

Probing the two-quasiparticle Kπ=8+ isomeric structure and enhanced stability in the proton drip-line nuclei

Ab initio charge form factors and radii of light isoscalar nuclei: Role of the two-body charge density

Affiliations

Shell and cluster structures in $^{20}$ Ne in the variation of multiple bases of the antisymmetrized molecular dynamics

Probing the two-quasiparticle $K^{π} = 8^{+}$ isomeric structure and enhanced stability in the proton drip-line nuclei