Nuclear Theory·nucl-th

Thursday·September 18, 2025

9 papers—8 primary·1 cross-listed

01
[Submitted on 16 Sept 2025]
Pairing Strength and Quadrupole-Soft Tin Isotopes
Le-Anh Nguyen · Minh-Loc Bui · Panagiota Papakonstantinou · Calvin W. Johnson · Naftali Auerbach
Background: Understanding the experimental $B (E 2)$ values for Sn isotopes around $^{110}$ Sn has been a significant challenge in nuclear structure studies for over a decade. Both experimental data and many, though not all, calculations suggest a picture of the light Sn isotopes as being quadrupole-soft, that is, spherical, yet easy to deform. Purpose: To investigate the delicate interplay of quadrupole deformation and pairing correlations in these nuclides. In particular, by using slightly enhanced pairing, we ask: can we generate spherical mean-field solutions that describe the data? Method: First, we apply the standard spherical Skyrme HFBCS-QRPA calculation with default pairing parameters, allowing us to identify nuclides that are unstable against quadrupole deformation among Sn isotopes. Next, we moderately enhance the pairing strength to reproduce the experimental binding energy in the deformation-unstable isotopes. Result: Within our choice of Skyrme parameters and use of density-independent pairing, this moderate adjustment sufficiently stabilizes the HFBCS ground states against deformation, ensuring a successful QRPA calculation and, more importantly, leading to more realistic properties for the quadrupole $2^{+}$ states. Conclusion: Careful attention to the sensitive interplay of pairing and shell effects in deformation-soft nuclides can be crucial to their correct descriptions. This sensitivity can be exploited to optimize the treatment of pairing in phenomenological approaches such as the present Skyrme-QRPA.
Comments:
7 pages, 5 figures, to be submitted to Physical Review C
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.13475 [pdf]
0 citations
02
[Submitted on 17 Sept 2025]
Octupole correlations in $^{220, 222, 224, 226}$ Rn
Yi-Ming Jiang · Xiao Lu · Shan-Gui Zhou
The octupole correlations in $^{220, 222, 224, 226}$ Rn are investigated by using multi-dimensionally constrained covariant density functional theory. The ground-state properties and potential energy surfaces are analyzed, revealing that octupole deformation appears in $^{222, 224}$ Rn, but not in $^{220, 226}$ Rn. The relationship between pairing correlations and octupole deformation is examined, showing that the neutron pairing energy decreases as octupole deformation develops, whereas the proton pairing energy shows the opposite behavior. The microscopic origin of octupole correlations in these radon isotopes are explored based on an examination of the single-particle levels near the Fermi surface and a schematic two-level model. Experiments have indicated that these isotopes undergo octupole vibrations and the present prediction of octupole deformation in $^{222, 224}$ Rn awaits further confirmation.
Comments:
9 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.13613 [pdf]
PRC(2026)·0 citations
03
[Submitted on 17 Sept 2025]
$Δ (1232)$ production in the $γ p \to ϕ π p$ reaction
Ya-Ke Chen🇨🇳 · Yi Pan🇨🇳 · Bo-Chao Liu🇨🇳
In this work, the production of baryon resonances in the $γ p \to ϕ π p$ reaction near threshold is investigated within an effective Lagrangian approach. incorporates intermediate resonances, including $Δ (1232)$ , $N (1440)$ , $N (1520)$ , and $N (1535)$ , alongside non-resonant background contributions. The results indicate that the reaction is dominated by the $Δ (1232)$ excitation near threshold. A key focus of this study is the exploration of the $a_{0} (980)$ meson exchange in the $Δ (1232)$ production, as this reaction offers a unique opportunity to probe the poorly known $Δ (1232) N a_{0}$ coupling. We demonstrate that the parity asymmetry ( $P_{σ}$ ), accessible through the $ϕ$ -meson's spin density matrix elements, serves as a suitable experimental observable to identify the contribution from the $a_{0} (980)$ exchange.
Comments:
8 pages, 5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2509.13630 [pdf]
PRD(2025)·2 citations
04
[Submitted on 17 Sept 2025]
Charge symmetry breaking effect in mirror {\Lambda} hypernuclei with Skyrme-Hartree-Fock model
Shi-jing Zha🇨🇳 · Suo Qiu🇨🇳 · H. Sagawa🇯🇵 · Xian-Rong Zhou🇨🇳
We study the charge symmetry breaking (CSB) effect in mirror hypernuclei using the deformed Skyrme Hartree-Fock (DSHF)+ Bardeen-Cooper-Schrieffer (BCS) model together with the CSB term and pairing interaction. Our model provides good account for the observations of CSB effect in mirror hypernuclei in the mass region of A = 7~16. We investigate the effect of deformation on the single-Lambda binding energy differences and we found that, in mirror hypernuclei with mass numbers A = 8 and A = 9, deformation has a noticeable impact on the energy difference.
Comments:
9 Pages, 2 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.13655 [pdf]
0 citations
05
[Submitted on 17 Sept 2025]
Global Trends of Nuclear Radii and Binding Energies from the NUCLEI-PACK Framework
H. M. Maridi
I present a proof-of-concept study of nuclear radii and binding energies within NUCLEI-PACK, a novel semi-classical framework based on optimized sphere packing of nucleons and clusters. In this approach, proton and neutron positions are determined through a constrained packing algorithm with uniform nucleon radii, followed by global optimization across the nuclear chart ( $1 \leq A \leq 250$ ). From these geometric configurations, I compute charge and matter radii, as well as binding energies. The model successfully reproduces global trends in nuclear size and stability, while maintaining transparency and computational efficiency. A fit of the Coulomb and surface terms of the semi-empirical mass formula shows remarkable agreement with theoretical expectations. These results establish the feasibility of NUCLEI-PACK as a systematic tool for describing nuclear bulk properties across the chart of nuclides.
Comments:
6 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.13750 [pdf]
1 citation
06
[Submitted on 17 Sept 2025]
Nonperturbative Heavy-Flavor Transport Approach for Hot QCD Matter
Tharun Krishna🇺🇸 · Ralf Rapp🇺🇸 · Yu Fu🇺🇸 · Steffen A. Bass🇺🇸 · Weiyao Ke🇨🇳
The heavy charm and bottom quarks are unique probes of the transport properties of the quark-gluon plasma (QGP) and its hadronization in high-energy nuclear collisions. A key challenge in this context is to embed the interactions of the heavy quarks in the expanding medium compatible with the strong-coupling nature of the QGP, and thus to unravel the underlying microscopic mechanisms. In the present work we progress toward this goal by combining recent $T$ -matrix interactions for elastic scattering with an effective transport implementation of gluon radiation, and apply these in a Langevin framework in a viscous hydrodynamic evolution. Hadronization of heavy quarks is evaluated using a modern recombination model with 4-momentum conservation, supplemented with fragmentation constrained by data in proton-proton collisions. Deploying this approach to charm-hadron observables in Pb-Pb collisions at the LHC yields fair agreement with experiment while also identifying areas of further systematic improvement of the simulations and its current input.
Comments:
7 pages, 4 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2509.13881 [pdf]
PLB(2025)·7 citations
07
[Submitted on 17 Sept 2025]
MEC-induced two-nucleon emission in neutrino-nucleus scattering
M.B. Barbaro🇮🇹 · V. Belocchi🇮🇹 · A. De Pace🇮🇹 · M. Martini🇫🇷
Meson-exchange currents (MEC) play a crucial role in the nuclear response to a leptonic probe, inducing the emission of two nucleons, the so-called 2p2h excitations. Here we report the results of our recent work \cite{Belocchi:2025eix}, in which we evaluated the 2p2h contribution to the $(ν_{μ}, μ^{-} p)$ neutrino cross section off a carbon target, which involves the simultaneous detection the outgoing muon and a proton in the final state. This process has recently been measured in long-baseline neutrino experiments, but no truly microscopic calculation for the 2p2h channel existed to be compared with these data until now. The calculation employs fully relativistic two-body currents and is carried out within the Relativistic Fermi Gas framework. It provides a generalization to the weak sector of the electromagnetic inclusive model developed in Ref.~\cite{DePace:2003spn} and an extension of the calculation to enable semi-inclusive predictions. A selection of our results for the semi-inclusive cross section versus the emitted proton variables is presented, both at fixed neutrino energy and folded with the T2K muon-neutrino flux.
Comments:
12 pages, 5 figures, Contribution to Forty Second International Workshop on Nuclear Theory Proceeding, Rila Mountains (Bulgaria), June 29 - July 5, 2025
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2509.13915 [pdf]
Nucl.Theor.(2025)·1 citation
08
[Submitted on 17 Sept 2025]
Dilated coordinate method for solving nuclear lattice effective field theory
Guangzhao He · Zhenyu Zhang · Teng Wang · Qian Wang · Bing-Nan Lu
We introduce a dilated coordinate method to address computational challenges in nuclear lattice effective field theory (NLEFT) for weakly-bound few-body systems. The approach employs adaptive mesh refinement via analytic coordinate transformations, dynamically adjusting spatial resolution to resolve short-range nuclear interactions with fine grids while efficiently capturing long-range wave function tails with coarse grids. Numerical demonstrations for two- and three-body systems confirm accelerated convergence towards infinite-volume limit compared to uniform lattices, particularly beneficial for accessing highly excited states and shallow bound states near the continuum threshold. This method establishes a foundation for \textit{ab initio} studies of exotic nuclear systems near the dripline and light hypernuclei, with direct extensions to scattering and reaction processes.
Comments:
12 pages, 11 figures, version accepted by Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Lattice (hep-lat)
arXiv:
2509.13967 [pdf]
PRC(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE