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Nuclear Theory·nucl-th

Thursday·July 3, 2025

14 papers—7 primary·7 cross-listed

All14Primary7Cross-lists7
  1. 01

    [Submitted on 2 Jul 2025]

    From bare two-nucleon interaction to nuclear matter and finite nuclei in a relativistic framework

    Shihang Shen🇨🇳 · Jun-Xu Lu🇨🇳 · Li-Sheng Geng🇨🇳 · Jie Meng🇨🇳 · Wei-Jiang Zou🇨🇳

    Understanding nuclear forces, infinite nuclear matter, and finite nuclei within a unified framework has remained a central challenge in nuclear physics for decades. While most \textit{ab initio} studies employ nonrelativistic Schrödinger-equation frameworks, this work offers a relativistic perspective. Using a leading-order (LO) relativistic chiral interaction, we describe two-nucleon scattering via the Thompson equation, symmetric nuclear matter, and medium-mass nuclei (Ca, Ni, Zr, Sn) via the relativistic Brueckner-Hartree-Fock theory. Systematic uncertainties from regulator cutoffs and interaction parameters are analyzed. The empirical saturation region of nuclear matter is reproduced, and the binding energies and charge radii of medium-mass nuclei agree reasonably well with experimental data, significantly improving the ``Coester line". These results highlight that the relativistic approach, employing a leading-order chiral force with only four low-energy constants and no three-nucleon forces, can capture the most important dynamics and offer a complementary pathway to address longstanding challenges in nuclear \textit{ab initio} studies.

    Comments:
    15 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2507.01257 [pdf]
    PRC(2026)·5 citations
  2. 02

    [Submitted on 2 Jul 2025]

    Impact of shape fluctuations on nuclear Schiff moments in heavy octupole-deformed nuclei

    E. F. Zhou · J. M. Yao · J. Engel · J. Meng

    Permanent electric dipole moments (EDMs) are among the most sensitive probes of CP violation beyond the Standard Model. In diamagnetic atoms, the EDM is determined primarily by the nuclear Schiff moment, whose uncertainty limits the interpretation of current and future EDM searches. For the experimentally most promising octupole-deformed nuclei, however, existing Schiff-moment calculations have largely relied on the rigid-shape approximation. Here we report the first fully microscopic beyond-mean-field study of Schiff moments in the heavy octupole-deformed nuclei Ra, Th, and Pa, based on multireference covariant density functional theory (MR-CDFT) with symmetry restoration and quadrupole--octupole shape mixing. The results show that collective shape fluctuations reduce the Schiff moments by factors of two to four. Furthermore, the Schiff moments of Th and Pa are predicted to exceed that of Ra by more than an order of magnitude, largely due to the near-degenerate parity doublets predicted by MR-CDFT. This work establishes a microscopic framework for calculating Schiff moments in heavy octupole-deformed nuclei, providing essential nuclear-structure input for ongoing and future EDM searches.

    Comments:
    6 pages, 2 figures and 1 table
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Atomic Physics (physics.atom-ph)
    arXiv:
    2507.01369 [pdf]
    7 citations
  3. 03

    [Submitted on 2 Jul 2025]

    Pion properties in isospin-asymmetric nuclear matter using in-medium chiral perturbation theory

    Kihong Kwon🇯🇵 · Yamato Suda🇯🇵 · Stephan Hübsch🇯🇵 · Daisuke Jido🇯🇵

    We compute the density dependence of in-medium pion properties, such as mass, wave function renormalization, and decay constant in the correlation function approach, and how they change under the influence of isospin-asymmetric nuclear matter. To this end, we use in-medium chiral perturbation theory to compute the relevant Feynman diagrams up to two-loop diagrams. Our results show that the isospin asymmetry of the nuclear matter splits these quantities into three separate values, corresponding to the three pions. Consequently, the tendency of each in-medium pion mass, wave function renormalization, and decay constant is dependent on the density and the neutron-to-proton ratio of nuclear matter. We also derive an in-medium Gell-Mann--Oakes--Renner relation which is valid for isospin-asymmetric nuclear matter and investigate to what extent it holds within our calculations.

    Comments:
    23 pages, 3 figures, 4 tables
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2507.01398 [pdf]
    PRC(2025)·1 citation
  4. 04

    [Submitted on 2 Jul 2025]

    Bremsstrahlung emission accompanying ternary fission of \isotope[252]{Cf}

    Sergei P. Maydanyuk (1, 2 and 3) · Ju-Jun Xie (1, 4 and 5) · Sergei O. Omelchenko (3) ((1) Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences, Huizhou, China, (2) Wigner Research Centre for Physics, Budapest, Hungary, (3) Institute for Nuclear Research, National Academy of Sciences of Ukraine, Kyiv, Ukraine, (4) Heavy Ion Science and Technology Key Laboratory, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China, (5) School of Nuclear Sciences and Technology, University of Chinese Academy of Sciences, Beijing, China)

    \textbf{Background} In ternary fission, bremsstrahlung photons are emitted but those have never been studied yet theoretically and experimentally. In other reactions, bremsstrahlung has been studied for a long time. \textbf{Purpose} To clarify which new information about ternary fission can be obtained from study of bremsstrahlung emission accompanying the ternary fission of \isotope[252]{Cf}. \textbf{Methods} A new quantum model of emission of bremsstrahlung photons accompanying ternary fission of heavy nuclei with -particle as light charged particle is developed. The model takes into account geometry and dynamics of ternary fission. \textbf{Results} We present the theoretical results on the bremsstrahlung emission in the ternary fission of the \isotope[252]{Cf} nucleus. High sensitivity of the bremsstrahlung spectra is established by the model concerning to the following aspects of the ternary fission, and the theoretical calcualtions are in agreement with the preliminary experimental data. It is found that: (a) Photons are emitted with highest intensity in case of perpendicular motion of the \,particle concerning to fission axis; (b) Relative motion between heavy fragments reinforces significantly bremsstrahlung, leaving of -particle concerning to system of heavy fragments is less important; (c) Relative motion between two heavy fragments is faster, bremsstrahlung is more intensive. \textbf{Conclusions} Theoretical study of bremsstrahlung in ternary fission of the \isotope[252]{Cf} nucleus shows high sensitivity of bremsstrahlung spectra on the geometry and dynamics of ternary fission process. It is expected that new information can be obtained by the model when new experimental measurements of bremsstrahlung in ternary fission of the \isotope[252]{Cf} nucleus are available.

    Comments:
    14 pages, 7 captured figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex)
    arXiv:
    2507.01451 [pdf]
    J.Phys.A(2026)·0 citations
  5. 05

    [Submitted on 2 Jul 2025]

    Probing the tetrahedral clusters in relativistic O + O collisions

    Jin-Yu Hu🇨🇳 · Hao-jie Xu🇨🇳 · Xiaobao Wang🇨🇳 · Shi Pu🇨🇳

    Relativistic O +O collisions probe the Quark-Gluon Plasma formed in small systems, while their collective phenomena illuminate the structure of O. Recently, various configurations of O from \textit{ab initio} calculations were implemented in heavy-ion models, such as the hydrodynamic model and a multiphase transport model (AMPT) to study cluster effects in relativistic O +O collisions. However, divergent predictions across configurations and models complicate interpretations. In this Letter, we isolate the impact of multi-nucleon correlations in relativistic O +O collisions while fixing the one-body density distribution of O. Our results show that the normalized ratios and effectively probe the effects of one-body density (e.g., tetrahedral symmetry) and multi-nucleon correlations (e.g., clusters). These observables provide critical constraints for refining heavy-ion models, essential for investigating cluster configurations in light nuclei through relativistic heavy-ion collisions.

    Comments:
    6 page, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2507.01493 [pdf]
    7 citations
  6. 06

    [Submitted on 2 Jul 2025]

    Ab Initio Complex Scaling and Similarity Renormalization Group for Continuum Properties of Nuclei

    Osama Yaghi🇫🇷 · Guillaume Hupin🇫🇷 · Petr Navrátil🇨🇦

    We introduce a novel \abinitio many-body method designed to compute the properties of nuclei in the continuum. This approach combines well-established techniques, namely the Complex Scaling (CS) and Similarity Renormalization Group (SRG) methods while employing the translationally invariant No-Core Shell Model (NCSM) as a few-body solver. We demonstrate that this combination effectively overcomes numerical limitations previously encountered in exploring continuum properties of light nuclei with standard many-body techniques, and at the same time makes less imperative the need for a continuous set of basis states for the continuum. To benchmark the method for applications in the many-body sector, we apply it to the \textsuperscript{4}He system, where semi-exact calculations within a finite basis are feasible. Our extrapolated results agree with exact calculations already published in the literature. We argue that different NN parametrizations of chiral EFT Hamiltonians will not permit to reproduce evaluated resonance properties of \textsuperscript{4}He. As an application, we showcase the case of the tetraneutron. This work enables the application of the method to -mass systems, providing a reliable representation of the initial Hamiltonian and its continuum properties.

    Comments:
    7 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2507.01595 [pdf]
    2 citations
  7. 07

    [Submitted on 2 Jul 2025]

    Transmutation of O and Ne at the Large Hadron Collider

    Govert Nijs🇨🇭 · Wilke van der Schee🇨🇭

    In July 2025 the Large Hadron Collider (LHC) will collide OO and NeNe isotopes in a quest to understand the physics of ultrarelativistic light ion collisions. One particular feature is that there are many smaller isotopes with the exact same charge over mass ratio that potentially can be produced and contaminate the beam composition. Using the Trajectum framework together with the GEMINI code we provide an estimate of the production cross-section and its consequences. A potential benefit could be the interesting measurement of the multiplicity and mean transverse momentum of OHe collisions.

    Comments:
    3 pages, 3 figures and an appendix. v2: added figure 4. v3: added Ne-He, matches published version. The Trajectum code can be found at https://sites.google.com/view/govertnijs/trajectum , data points included in source
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2507.01659 [pdf]
    PLB(2026)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE