PaperPanorama

Nuclear Theory·nucl-th

Thursday·August 27, 2026

10 papers—5 primary·5 cross-listed

All10Primary5Cross-lists5
  1. 01

    [Submitted on 24 Aug 2026]

    Spectroscopy of 211,213,215Pb isotopes and seniority properties

    Larry Zamick · Praveen Srivastava

    We first consider lead isotopes with valence neutrons in the g9/2shell. We especially compare 211Pb (n=3), 213Pb (n=5) and 215Pb (n=7), 213Pb being at mid-shell. Motivated by the fact the J = 21/2+ and J =3/2+ states are pure seniority v=3 states for both n=3 and n=5, we compare the energy splitting E(J=21/2+)-E(J=3/2+) for various interactions. We then discuss the position of the lowest J=3/2+ state in both n=3 and n=5, although, this state has not been found experimentally. Calculations with configurations beyond g9/2 are also considered. We next address the fact that the J=21/2+ state is isomeric for both n=3 and n=5.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2608.24951 [pdf]
    IJMPE(2026)·0 citations
  2. 02

    [Submitted on 26 Aug 2026]

    Joint cluster-EFT analysis of N -delayed spectra and -C scattering

    Jubin Park · Myeong-Hwan Mun · Shung-Ichi Ando

    The -delayed decay (BDAD) of N probes the -wave -C continuum relevant to the low-energy transition of CO. We analyze the spectra of Azuma \textit{et al.} and Tang \textit{et al.} within cluster effective field theory, fitting each independently together with the same elastic-scattering data. The baseline eight-parameter fits yield for the Azuma spectrum and for the Tang spectrum, substantially improving upon the corresponding fixed-propagator values of 4.06 and 3.56, respectively. The raw simultaneous fit yields , , and for the Azuma, Tang, and elastic-scattering data, respectively. With sector-balanced weighting, the corresponding values are 3.308, 8.993, and 6.466, respectively. Thus, reducing the relative elastic weight improves the BDAD sectors but does not recover the quality of the independent fits. The common strong parameters and normalization ratio remain stable, whereas the fitted weak-current coefficients depend on the objective. The two spectra are separately compatible with a common strong continuum, but the minimal common weak-current amplitude does not reproduce them simultaneously; its fitted coefficients also depend on the objective. These results define the experimental and model sensitivities that must be propagated in a future unified analysis including radiative capture.

    Comments:
    37 pages, 11 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2608.25252 [pdf]
    0 citations
  3. 03

    [Submitted on 26 Aug 2026]

    Impact of Nuclear Level Density on -Process Rare-Earth Peak Nucleosynthesis

    Hang Xu · Peng-Xiang Du · Jian Li · Dong-Liang Fang

    The rare-earth peak () is a prominent feature of the -process, and previous theoretical studies suggest that it is possibly linked to local nuclear structural effects. However, the nuclear level density (NLD), a physical quantity directly reflecting these properties, has been largely overlooked compared to other structural properties such as nuclear masses. To address this, we perform -process simulations across three astrophysical scenarios using neutron-capture rates derived from six distinct NLD models. Our results reveal that microscopic models yield systematic deviations in NLD relative to phenomenological ones, leading to critical impacts on nucleosynthesis. Specifically, systematic NLD differences in even- nuclei redirect the nuclear flow, accelerating the early formation of the rare-earth peak and temporarily enhancing its magnitude. This underlying structural shift also fundamentally alters the -process sensitivity to the neutron-capture rate, effectively eliminating its dependence on the odd-even nature of protons. Overall, these findings demonstrate that the internal nuclear structure encoded within NLDs can collectively induce a global redirection of the nucleosynthesis pathway, highlighting the critical need for self-consistent microscopic inputs in future simulations.

    Comments:
    14 pages, 8 figures. Accepted for publication in The Astrophysical Journal
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2608.25440 [pdf]
    0 citations
  4. 04

    [Submitted on 26 Aug 2026]

    Directional correlations in nuclear charge-radius model residuals enable extrapolation with calibrated uncertainties

    Debodyuti Kar · Soumya Bagchi · Timo Dickel · Rituparna Kanungo

    We identify a pronounced directional anisotropy in the residuals between measured nuclear charge radii and two structurally distinct global models: the phenomenological Weizsäcker--Skyrme formula (WS*) and the microscopic Hartree--Fock--Bogoliubov model (HFB-25). In both cases, the residuals remain correlated over several neutron steps along isotopic chains but decorrelate almost completely after a single proton step along isotonic chains. This common pattern, reinforced by a strong correlation between the two residual fields (), points to a shared deficiency of both global descriptions rather than a model-specific artefact. Motivated by this geometry, we introduce ARCUS (Anisotropic Residual Calibration with Uncertainty Scaling), which applies an anisotropic kernel-regression correction with empirically calibrated prediction intervals. In out-of-fold cross-validation, ARCUS reduces the root-mean-square errors of both WS* and HFB-25 by approximately a factor of two. On an independent, temporally blind test set of 129 nuclei, its prediction intervals retain coverage close to nominal under extrapolation. An isotropic kernel matched to the same cross-validation coverage instead substantially overestimates uncertainties on the blind set, showing that reliable calibration transfer depends on encoding the directional residual structure. In regions with anomalous structure, such as around Ca, ARCUS keeps its prediction intervals wide enough to cover the increased errors, rather than yielding overconfident point predictions. We also extend these calibrated predictions to 1008 unmeasured nuclei near known isotopic chains, ranked by uncertainty to support the future charge-radius measurements.

    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2608.25624 [pdf]
    0 citations
  5. 05

    [Submitted on 26 Aug 2026]

    Evidence for Quartet Binding of Valence Neutrons in He

    Young-Ho Song · Yuan-Zhuo Ma · Dean Lee

    Multimodal neutron superfluidity predicts quartets formed as bound states of two spin-singlet -wave neutron pairs. We present evidence that the four valence neutrons of He realize the finite-system analogue. Quartet binding depends not only on the strength of neutron-neutron attraction but also on the number and symmetry of sufficiently strong attractive pair modes. Pauli blocking limits reuse of the same pair structure, while additional modes can provide extra binding. A partial-wave analysis of the neutron-neutron interaction in Daejeon16 no-core shell-model calculations identifies cooperative pairing and additional attraction as the dominant neutron-neutron contributions to this nonadditive binding, while density cumulants reveal connected four-neutron correlations.

    Comments:
    15 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2608.25883 [pdf]
    0 citations
  6. 06

    [Submitted on 25 Aug 2026] (cross-list from hep-ph)

    Resonant Induced Orbital Electron Capture: Novel method for low-energy detection

    Evgeny Akhmedov🇩🇪 · Thierry Lasserre🇩🇪 · Leonardo Maturi🇩🇪

    We propose a novel approach to detecting low-energy electron antineutrinos based on the induced capture of orbital electrons by nuclei. This process is resonant, requiring the antineutrino energy to precisely match the energy difference between the final and initial atomic systems. For continuous-spectrum sources, the resonance conditions can be satisfied without fine-tuning, and the effective cross sections depend on the spectral intensity of the flux at the resonance rather than on the neutrino energy itself. This opens the possibility of detecting neutrinos of never previously probed low energies. We identify a number of candidate nuclides that allow transitions to excited states of the daughter nuclei corresponding to resonant energies below the inverse decay threshold of 1.8 MeV, and we consider a distinctive atomic-nuclear coincidence signature for background rejection. We discuss implications of the proposed method for detecting low-energy reactor neutrinos, geoneutrinos, and keV-scale thermal solar neutrinos. Applications to neutrino oscillation experiments and to reactor monitoring are also briefly discussed.

    Comments:
    7 pages, 3 figures, 1 table
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2608.25001 [pdf]
    0 citations
  7. 07

    [Submitted on 26 Aug 2026] (cross-list from hep-ph)

    Robust Finite-Momentum Instabilities in Dense Matter

    André G. da Silva🇧🇷 · Ricardo L. S. Farias🇧🇷 · Theo Motta🇧🇷 · William R. Tavares🇵🇹

    The predicted extent of inhomogeneous chiral phases in effective models of quantum chromodynamics is notoriously sensitive to ultraviolet regularization. We show that this sensitivity is largely artificial. In the two-flavor Nambu--Jona-Lasinio model, conventional implementations of three-dimensional cutoff, Pauli--Villars, and proper-time regularization produce strongly different finite-momentum instability regions. Once ultraviolet regulators are restricted to genuinely divergent vacuum contributions, however, all three prescriptions yield nearly identical stability diagrams. Both the onset of the moat regime and the subsequent finite-momentum instability become quantitatively robust. The apparent scheme dependence originates from regulating ultraviolet-finite medium contributions associated with the Fermi-surface response. Our results identify spatially modulated chiral correlations as a genuine property of the dense medium rather than an artifact of the ultraviolet prescription.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2608.25857 [pdf]
    0 citations
  8. 08

    [Submitted on 26 Aug 2026] (cross-list from cond-mat.supr-con)

    Fluxtube Bouquets and Type-1.5 Clustering in Superfluid Neutron Star Cores

    Adarsh Karekkat · Gabriele Montefusco · Marco Antonelli

    We study mesoscopic configurations of a neutron superfluid coupled to a proton superconductor in the outer core of a neutron star. The condensates are described by a two-component Ginzburg-Landau free energy with local couplings, neglecting genuine phase-gradient entrainment. In two spatial dimensions, we minimize the free energy using quasi-periodic boundary conditions and constrained phase-imprinting calculations to study vortex-fluxtube and fluxtube-fluxtube interactions. We find that, for locally attractive couplings in the free energy, vortex-fluxtube overlap is energetically favoured and several pre-existing proton fluxtubes can bind around a neutron vortex, forming finite vortex-centred aggregates that we call fluxtube bouquets. These bouquet configurations may become so dense that a vortex can effectively accommodate several quanta of magnetic flux. We also confirm the possible presence of a type-1.5-like regime and find that it survives in the zero-entrainment regime considered here. In this type-1.5 regime, the fluxtube-fluxtube interaction is repulsive at short distances and attractive at intermediate distances, leading to self-assembled clusters while the individual fluxtubes remain topologically distinct. Possible implications for dissipative coupling and transport in neutron stars are discussed.

    Comments:
    Preprint version, 16 pages, 12 figures. Comments are welcome!
    Subjects:
    Superconductivity (cond-mat.supr-con); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2608.25943 [pdf]
    0 citations
  9. 09

    [Submitted on 26 Aug 2026] (cross-list from hep-ph)

    Jet Quenching Meets Gluon Saturation

    Paul Caucal🇫🇷 · Kevin Eisenberg🇺🇸 · Yacine Mehtar-Tani🇺🇸

    We present a theoretical framework for jet fragmentation in heavy-ion collisions based on the resummation of large energy logarithms. Exploiting the hierarchy of scales characteristic of jet quenching, we show that the jet function obeys the Banfi-Marchesini-Smye evolution equation, with medium-induced energy loss and color decoherence encoded in the initial condition. This structure reveals a close correspondence with saturation physics. In particular, the coherence angle emerges as the analog of the saturation scale and exhibits the same asymptotic scaling behavior under nonlinear evolution. As a proof of principle, we compute the jet nuclear modification factor to quantify the interplay between vacuum radiation and medium-induced color decoherence. Our framework provides a unified perturbative description of vacuum-like parton showers, medium-induced radiation, and color-coherence effects, paving the way for precision studies of jet quenching at RHIC and the LHC.

    Comments:
    10 pages, 4 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2608.25983 [pdf]
    0 citations
  10. 10

    [Submitted on 26 Aug 2026] (cross-list from hep-ph)

    Color Coherence and the Soft Structure of QCD Jets in Vacuum and the QGP

    Paul Caucal🇫🇷 · Yacine Mehtar-Tani🇺🇸

    We formulate a theoretical framework for the evolution of QCD jets in vacuum and in the quark--gluon plasma through the resummation of large energy logarithms. Exploiting the strong hierarchy between the hard scale of the jet and the energy scale associated with jet energy loss, we show that jet observables near threshold can be formulated in terms of Wilson-line correlators obeying Banfi-Marchesini-Smye (BMS) evolution. In this description, soft radiation resolves the internal color structure of the jet, leading to a hierarchy of non-linear evolution equations that govern the evolution of color coherence and the emergence of decoherent energy loss. For jets propagating through a QCD medium, we demonstrate that medium-induced interactions modify the boundary conditions of the evolution while leaving its ultraviolet structure unchanged. This separation of scales provides a unified description of vacuum-like radiation, medium-induced energy loss, and color coherence. In the large- limit, the resulting evolution is closely related to the Balitsky-Kovchegov equation of high-energy QCD, allowing concepts from saturation physics to be applied to jet quenching. In particular, the medium coherence angle plays a role analogous to the saturation scale and acquires the same asymptotic scaling behavior under evolution. Our framework establishes a perturbative foundation for the study of color coherence effects in jet quenching and provides a unified picture of soft jet evolution in vacuum and in dense QCD matter.

    Comments:
    49 pages, 8 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2608.25984 [pdf]
    0 citations

Affiliations

first authorsco-authorsvia INSPIRE