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Nuclear Theory·nucl-th

Wednesday·November 27, 2024

11 papers—7 primary·4 cross-listed

All11Primary7Cross-lists4
  1. 01

    [Submitted on 26 Nov 2024]

    Universal Wong formula for capture cross sections from light to super-heavy systems

    Ning Wang · Jinming Chen · Yicheng Wang · Hong Yao

    A universal Wong formula is proposed with refined model parameters for a systematic description of the capture cross sections for heavy-ion fusion reactions from C+C to Ni+U, in which the barrier parameters and the barrier distribution are determined by the entrance-channel nucleus-nucleus potential based on the Skyrme energy density functional. With introducing a constraint to the width of the barrier distribution and a pocket-depth dependent barrier radius, the capture excitation functions for a number of fusion reactions involving different nuclear structure effects are remarkably well reproduced, particularly for the reactions between light nuclei and those forming super-heavy nuclei. The systematic decreasing behavior of the geometric radii with the depth of capture pocket due to the influence of deep inelastic scattering is clearly observed in the TDHF calculations for super-heavy systems. The predicted capture cross sections for Cr + U at above barrier energies are evidently smaller than the corresponding results of more asymmetric projectile-target combination Ti + Pu due to the shallower capture pocket in Cr+U.

    Comments:
    6 figures, accepted for publication in Phys. Rev. C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2411.17019 [pdf]
    PRC(2025)·3 citations
  2. 02

    [Submitted on 26 Nov 2024]

    Impact of Nuclear Deformation of Parent and Daughter Nuclei on One Proton Radioactivity Lifetimes

    A. Jain · Pranali Parab · G. Saxena · Mamta Aggarwal

    The influence of nuclear deformation on proton-decay half-lives has been systematically studied in microscopic theoretical frameworks for a wide range of nuclei with Z<82. Correlation between 1p-decay half-lives and the deformed nuclear shapes of both the parent and daughter nuclei has been investigated. Since the deformations of proton emitters and their residual nuclei impact the potential barrier and disintegration energy which are crucial for the accurate determination of half-lives, we incorporate the nuclear deformations of both the emitters and residues in a phenomenological manner and propose a new semi-empirical formula to estimate the 1p-decay half-lives. The robustness of this formula is demonstrated by the accurate predictions of the measured values while making it reliable for forecasting the properties of other potential proton emitters. The phenomenon of shape coexistence as observed in several proton emitters and their respective daughter nuclei, is particularly signicant in this context due to secondary minima in the potential energy surfaces of both the nuclei. Accounting for these factors signicantly affects the estimation of half-lives and branching ratios by introducing additional decay pathways and altering transition probabilities between different nuclear shapes.

    Comments:
    16 pages, 3 figures, 5 tables, Published in Scientific Reports (Nature Portfolio)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2411.17112 [pdf]
    Sci.Rep.(2024)·3 citations
  3. 03

    [Submitted on 26 Nov 2024]

    FNe reaction rate and the puzzling calcium abundance in metal poor stars

    G.X. Dong🇨🇳 · X.B. Wang🇨🇳 · N. Michel🇨🇳 · M. Płoszajczak🇫🇷

    The FNe reaction is the only process to break out of the CNO cycle at temperature below 0.1 GK and may serve as the origin of calcium in first generation of stars after the Big Bang. In the recent measurement, the Jinping Underground Nuclear Experiment (JUNA) obtained the rate of FNe reaction, significantly larger than the previously recommended values. In this work, we perform the theoretical studies of the FNe reaction using the Gamow shell model in the coupled-channel representation (GSM-CC). At temperature around 0.1 GK, the predicted rate by GSM-CC is close to the rate found by JUNA. Thus, based on GSM-CC, the break-out reaction FNe from the CNO-cycle might win over its competing reaction FO, and produce enough calcium in the metal poor stars.

    Comments:
    6 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2411.17243 [pdf]
    PRC(2024)·4 citations
  4. 04

    [Submitted on 26 Nov 2024]

    A solvable model for spin polarizations with flow-momentum correspondence

    Anum Arslan🇨🇳 · Wen-Bo Dong🇨🇳 · Guo-Liang Ma🇨🇳 · Shi Pu🇨🇳 · Qun Wang🇨🇳

    We present an analytically solvable model based on the blast-wave picture of heavy-ion collisions with flow-momentum correspondence. It can describe the key features of spin polarizations in heavy-ion collisions. With the analytical solution, we can clearly show that the spin polarization with respect to the reaction plane is governed by the directed flow, while the spin polarization along the beam direction is governed by the ellipticity in flow and in transverse emission area. There is a symmetry between the contribution from the vorticity and from the shear stress tensor due to the flow-momentum correspondence. The solution can be improved systematically by perturbation method.

    Comments:
    RevTex 4, 12 pages, 8 figures, 2 tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2411.17285 [pdf]
    PRC(2025)·8 citations
  5. 05

    [Submitted on 26 Nov 2024]

    Inner crust of neutron stars: Polymorphism and superconductivity in the liquid drop model

    Dmitry Kobyakov · Xavier Viñas

    Within the liquid drop model built up with the nuclear interaction parametrization Sk450, which is based on the chiral effective field theory, we calculate numerically the internal energy density for each of nuclear pasta phases and for the uniform nuclear matter. We provide quantitative arguments in favor of coexistence of various nuclear matter phases at a significant range of total pressure within the inner crust of neutron stars, a concept known as crystal polymorphism. Specifically, we find that differences of the internal energy per baryon for various phases are typically less than the thermal energy per a freedom degree at temperature about -- K, which sets the energetic scale for thermal fluctuations of state of Fermi liquid from the ground state. The nuclear energy contributions are described using the same parametrization Sk450 for the bulk, plain surface and curvature terms. We find that the introduction of the curvature correction changes the ground state in a relevant way. This may be understood as a consequence of the corresponding change in size of the nucleus, which significantly modifies the phase transition densities. Using the calculated structural parameters from liquid drop model, we explore the physical consequences of the expected Cooper pairing of protons in lasagna phase. In this case, we find a crossover between the discreet layered and the three-dimensional anisotropic regimes of superconductivity. Additionally, we study the magnetic stress in lasagna accounting for a rotational lag between superfluid neutrons and the crystal lattice, which is believed to develop naturally in pulsars and magnetars. Our results offer a preliminary insight into rich magnetic properties of the inner crust of neutron stars.

    Comments:
    Revised version. 25 pages, 11 figures, 3 tables
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Theory (hep-th); Plasma Physics (physics.plasm-ph)
    arXiv:
    2411.17303 [pdf]
    2 citations
  6. 06

    [Submitted on 26 Nov 2024]

    Isomer triplets in odd-odd transitional rare earth nuclei: unique features, orbital systematics and characterization

    N. Susshma · S. Deepa · K. Vijay Sai · R. Gowrishankar

    The existence of low-lying long-lived isomers, predominantly in odd-odd nuclei of the light rare-earth mass region, is investigated through an extensive survey of available nuclear data. The characteristics of these isomeric states and their systematics has revealed intriguing and unusual properties, including the identification of isomer triplets, a phenomenon specific to odd-odd deformed nuclei close to the transition region. This exclusive feature was observed in the following odd-odd nuclei, namely, 152Pm, 152Eu, 154Tb, 156Tb, 156Ho, 158Ho, 160Ho, 162Lu and 166Lu. We present a detailed overview of these isomer triplets by exploring the systematics of single-quasiparticle proton and neutron orbitals near the Fermi surface relevant in this mass region, to elucidate the factors responsible for their formation. The low-lying level structures of 156Tb and 154Tb, were constructed using the well-tested Two Quasiparticle Rotor Model to resolve the ambiguities in the spin, parity, energy and orbital configuration of these isomeric states. These results were extended to study the systematics of low-lying isomer triplets in the other five light rare-earth nuclei of interest. Our review and analysis of 1qp proton and neutron orbital systematics in the neighboring odd-mass isotopes and isotones highlights the crucial role of high-spin intruder neutron orbital in the formation of these isomer triplets.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2411.17407 [pdf]
    0 citations
  7. 07

    [Submitted on 26 Nov 2024]

    Lattice simulation of nucleon distribution and shell closure in the proton-rich nucleus Si

    Shuang Zhang · Serdar Elhatisari · Ulf-G. Meißner · Shihang Shen

    The proton-rich nucleus Si is studied using Nuclear Lattice Effective Field Theory with high-fidelity chiral forces. Our results indicate that Si is more tightly bound than Mg, thereby excluding the possibility of two-proton emission. The shell closure in Si is supported by the evolution of the state in the neighboring nuclei. We then focus on the charge radius and spatial distribution information of Si, considering the novel phenomena that may emerge due to the small two-proton separation energy and the shell closure. We present the distribution of the protons and neutrons obtained from our lattice simulation, revealing insights into the spatial arrangement of the nucleons. Moreover, the spatial localization of the outermost proton and neutron suggests that Si is a doubly magic nucleus. Furthermore, we develop the pinhole method based on the harmonic oscillator basis, which gives insight into the nuclear structure in terms of the shell model picture from lattice simulations. Our calculated occupation numbers support that and are the shell closures and show that the orbital component is minor in Si.

    Comments:
    5+4 pages, 3+2 figures
    Subjects:
    Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex)
    arXiv:
    2411.17462 [pdf]
    PLB(2025)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE