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Nuclear Theory·nucl-th

Thursday·May 15, 2025

6 papers—3 primary·3 cross-listed

All6Primary3Cross-lists3
  1. 01

    [Submitted on 13 May 2025]

    Symmetry properties of pair correlations in heavy deformed nuclei

    G. Palkanoglou · A. Gezerlis

    Nucleons are known to form pairing correlations with various types of spin-symmetries. Spin-singlet neutron-neutron and proton-proton pairing is abundant in the nuclear chart but spin-triplet and mixed-spin proton-neutron pairing correlations have also been predicted to form at least in the ground states of certain nuclei. A realistic candidate region is that of the lightest Lanthanides where it was recently demonstrated that the nuclear deformation expected to emerge enhances spin-triplet pairing correlations. In this paper we provide the details of the deformed multimodal Hartree-Fock-Bogolyubov theory that lead to this conclusion, as well as the details of the effects identified. We present in detail the response of different pairing correlations to various deformation modes and calculate their signatures in the odd-even staggering of masses. This paper provides a detailed discussion, and some resolutions, on the long-standing question ``what is the effect of nuclear deformation on the various pairing correlations?''

    Comments:
    17 pages, 14 figures; v2 includes feedback from the community
    Subjects:
    Nuclear Theory (nucl-th); Superconductivity (cond-mat.supr-con); Nuclear Experiment (nucl-ex)
    arXiv:
    2505.08879 [pdf]
    2 citations
  2. 02

    [Submitted on 14 May 2025]

    A renormalizable theory for not-so-light nuclei

    L. Contessi🇫🇷 · M. Schäfer🇨🇿 · A. Gnech🇺🇸 · A. Lovato🇺🇸 · U. van Kolck🇫🇷

    We present an improved action for Pionless Effective Field Theory (EFT). Previous formulations of renormalizable nuclear EFTs have encountered instabilities in systems with more than four nucleons. We resolve this issue by introducing a finite interaction range at leading order, which is compensated for in perturbation theory at next-to-leading order. Calculated ground-state energies of He, Li, C, and O converge and agree with experiment within theoretical uncertainties. This first successful implementation of systematic renormalizability beyond the lightest nuclei enables not only applications to larger nuclei but also extensions to other EFTs in the strong-coupling regime.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2505.09299 [pdf]
    7 citations
  3. 03

    [Submitted on 14 May 2025]

    Photonuclear Tomography in Ultraperipheral Heavy-Ion Collisions

    J.D. Baker🇺🇸 · C.A. Bertulani🇺🇸 · Victor P. Goncalves🇧🇷

    We present a theoretical investigation of photonuclear tomography as a novel technique for probing the internal structure of nuclei. In this approach, ultraperipheral heavy-ion collisions (UPCs) serve as a source of intense fluxes of virtual photons, which induce coherent production of vector mesons. By analyzing the probabilities and cross sections of these photon-induced processes, we propose a methodology for reconstructing the spatial distribution of nucleons within the nucleus. Our framework provides a systematic way to access information on the nuclear geometry probed in UPCs, offering new opportunities for studies of nuclear structure using particle production as a probe. Numerical calculations for selected examples illustrate the feasibility and potential of this method.

    Comments:
    10 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2505.09348 [pdf]
    PRC(2025)·1 citation
  4. 04

    [Submitted on 14 May 2025] (cross-list from astro-ph.HE)

    Neutron Decay Anomaly and Its Effects on Neutron Star Properties

    H. C. Das · G. F. Burgio

    We investigate the effects of dark matter (DM) on neutron star (NS) properties using the neutron decay anomaly model within the relativistic mean-field (RMF) framework. Three nucleonic models (HCD0-HCD2) are developed, satisfying astrophysical constraints such as the maximum NS mass (), the NICER mass-radius limits, and the tidal deformability constraint from the GW170817 event. The equation of states of the NS admixed with DM (DMANS) are calculated by incorporating the self-interactions between them. The macroscopic properties, such as mass, radius, and tidal deformability of the NSs, are obtained for HCD models along with five others by varying self-interaction strength. By combining NS observations with scattering cross-section constraints from galaxy clusters, we explore model-dependent trends in the DM self-interaction parameter space. While the quantitative bounds may vary with hadronic model choice, our analysis offers insights into the interplay between DM interactions and NS observables within the RMF framework.

    Comments:
    14 pages, 5 fgures, and 1 table. Published in Universe
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2505.09190 [pdf]
    Universe(2025)·8 citations
  5. 05

    [Submitted on 14 May 2025] (cross-list from physics.med-ph)

    Evaluating the effectiveness of concrete and metal shields in photoneutron reduction: A Monte Carlo study

    Mohammad Hossein Jahanimehr · Seyed Mohammad Mahdi Abtahi

    Introduction: Neutrons are produced when photons interact with parts of the accelerator, materials in the treatment room, or the patient's body. These neutrons have significant biological effects due to their high quality factor, potentially leading to secondary cancers. Material and method: A Monte Carlo simulation was conducted using the MCNPX code to model an Elekta Infinity linear accelerator operating at 18 MV. The accelerator was situated inside a bunker measuring 7.4* 5 m2. To study photoneutron production and the effectiveness of shielding, various concrete mixtures were applied to the walls of the maze and treatment room. Results: Regardless of the modifications, both photon and neutron fluence decreased substantially as the distance from the maze entrance increased. The fluence reduction was more pronounced between the maze entrance and center. The lowest equivalent neutron doses behind the treatment room door were observed when Ord-Lim concrete was used, while the highest doses occurred with Gal-Bar concrete. Conclusion: The configuration of concrete layers within the treatment room and maze walls is a key factor influencing the changes in neutron dose behind the treatment room door. These variations result from differences in concrete composition and the way neutrons are absorbed in different setups.

    Subjects:
    physics.med-ph (physics.med-ph); Nuclear Theory (nucl-th)
    arXiv:
    2505.09245 [pdf]
    0 citations
  6. 06

    [Submitted on 14 May 2025] (cross-list from hep-ph)

    Pion in the Bethe-Salpeter approach with separable kernel

    S. Bondarenko (1,2)🇷🇺 · M. Slautin (1,2) ((1) Joint Institute for Nuclear Research, Dubna, Russia, (2) Dubna State University, Dubna, Russia)🇷🇺

    In the paper, the static and dynamic properties of the pion in the Bethe-Salpeter approach are considered. The rank-one separable kernel of the quark-antiquark interaction is used to solve the equation analytically. Multidimensional integrals describing pion properties are calculated by several numerical methods and compared with previous papers. An error in the calculation of the interaction part of the elastic pion form factor is found. Using the corrected results, the kernel parameters are refitted. The calculated static properties as well as transition and elastic form factors are presented in comparison with the recent experimental data.

    Comments:
    8 pages, 3 figures, 1 table
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2505.09421 [pdf]
    Phys.Part.Nucl.Lett.(2025)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE