PaperPanorama
FAQ

Nuclear Theory·nucl-th

Friday·September 20, 2024

13 papers—7 primary·6 cross-listed

All13Primary7Cross-lists6
  1. 01

    [Submitted on 18 Sept 2024]

    Systematic study of cross section for proton-induced reactions on Neodymium up to 65 MeV using TALYS-1.96 code

    A. Saha

    Systematic study of theoretical estimation of nuclear cross section of charged particle induced reactions on rare earth nuclei has been carried out. The production cross section of the Pm and Nd nuclei were calculated theoretically via proton induced reaction on neodymium using TALYS (version 1.96) code in the default mode, with different combination of nuclear models as well as using adjusted nuclear model parameters from reaction threshold to the proton energy upto 65 MeV. The theoretically computed results were compared with the experimental results taken from EXFOR database and literature, reported by various research groups. Moreover, the effect of the various Level Density Models (LDMs), Preequilibrium Models (PEs), Optical Model Potentials (OMPs), gamma Strength Functions (SFs) in the cross section calculation were taken into consideration. The present theoretical analysis will help to understand the theory of nuclear reaction models and improve the evaluated nuclear data libraries.

    Comments:
    15 pages, 13 figures, to be published in Chinese Physics C
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2409.12267 [pdf]
    CPC(2025)·1 citation
  2. 02

    [Submitted on 19 Sept 2024]

    Effective nucleus-nucleus potentials for heavy-ion fusion reactions

    Ning Wang · Jinming Chen · Min Liu

    Based on the Skyrme energy density functional and the reaction -value, we propose an effective nucleus-nucleus potential for describing the capture barrier in heavy-ion fusion processes. The 443 extracted barrier heights are well reproduced with a root-mean-square (rms) error of 1.53 MeV and the rms deviations with respect to 144 TDHF capture barrier heights is only 1.05 MeV. Together with the Siwek-Wilczyński formula in which the three parameters are determined by the proposed effective potentials, the measured capture cross sections at energies around the barriers can be reasonably well reproduced for a series of fusion reactions induced by not only nearly spherical nuclei but also the nuclei with large deformations such as Sm and U. The shallow capture pockets and small values of the average barrier radii play a role in the reduction of the capture cross sections for Cr and Ni induced reactions which are related to the synthesis of new super-heavy nuclei.

    Comments:
    21 pages, 6 figures, accepted for publication in Nucl. Sci. Tech
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2409.12383 [pdf]
    Nucl.Sci.Tech.(2025)·3 citations
  3. 03

    [Submitted on 19 Sept 2024]

    Benchmarking rotational correction energies in odd-mass nuclei

    Y. Li · E. F. Zhou · J. M. Yao

    Nuclear energy density functional theory (DFT) provides a microscopic approach to describing nuclear masses. By incorporating pairing correlations and deformation within DFT, nuclear masses can be predicted with sub-MeV accuracy. A crucial factor in achieving this precision is the dynamical correlation energy associated with restoring rotational symmetry, known as rotational correction energy (RCE). This correction is typically estimated using the cranking approximation in perturbation theory. In this work, we benchmark the results of these calculations against exact angular-momentum projection (AMP) for both even-even and odd-mass nuclei from light to heavy mass region, utilizing a covariant DFT framework. We find that the RCE, computed using the full moment of inertia (MoI) in the cranking approximation, closely matches the results from exact AMP for both even-even and odd-mass nuclei, with the exception of near-spherical even-even nuclei. For certain configurations in odd-mass nuclei, however, the RCEs can become abnormally small, a phenomenon linked to the divergence of the MoI. To address this, a regulator is introduced for the MoI of an odd-mass nucleus, the validity of which is examined through exact AMP calculations.

    Comments:
    9 pages with 6 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2409.12402 [pdf]
    PRC(2025)·3 citations
  4. 04

    [Submitted on 19 Sept 2024]

    Mixed phases of compact star matter in a unified mean-field approach

    Cheng-Jun Xia🇨🇳 · Toshiki Maruyama🇯🇵 · Nobutoshi Yasutake🇯🇵 · Toshitaka Tatsumi🇯🇵

    Based on an extended NJL model that treats baryons as clusters of quarks, we investigate the properties and microscopic structures of mixed phases for various types of first-order phase transitions in a unified manner, where the model parameters are fixed by reproducing nuclear matter properties and the binding energies of finite nuclei. In particular, based on the Thomas-Fermi approximation, we investigate the mixed phases arise from the liquid-gas phase transition of nuclear matter, chiral phase transition, and deconfinement phase transition in dense stellar matter adopting spherical and cylindrical approximations for the Wigner-Seitz cells. It is found that the geometrical structures do not emerge for chiral phases transition, while the droplet, rod, slab, tube, and bubble phases emerge sequentially as density increases for the liquid-gas and deconfinement phase transitions. Additional attractive interactions between strange quark matter and hyperons are observed as the deconfinement phase transition is entangled with chiral phase transition of quarks. The results obtained here should be useful to understand the properties and structures of dense stellar matter throughout compact stars and in particular the matter state in the core regions. Meanwhile, more extensive investigations in a three-dimensional geometry with large box sizes are necessary for our future study.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2409.12489 [pdf]
    PRD(2024)·4 citations
  5. 05

    [Submitted on 19 Sept 2024]

    Allowed and forbidden beta-decay log ft values of neutron-rich Pb and Bi isotopes

    Necla Cakmak · Jameel-Un Nabi · Arslan Mehmood · Asim Ullah · Rubba Tahir

    The beta-decay log ft values for 210 215Pb 210 215Bi and 210 215Bi 210 215Po transitions in the north east region of 208Pb nuclei are estimated using the proton neutron quasiparticle random phase approximation model. The pn-QRPA equations were solved using the schematic model approach. The Woods Saxon (WS) potential was inserted as a mean field basis and nuclei were treated as spherical. Allowed Gamow Teller (GT) and first forbidden (FF) transitions were investigated in the particle hole (ph) channel. The calculated log ft values of the allowed GT and FF transitions using the pn-QRPA(WS) were found closer to the experimental values. Later we performed calculation of beta-decay rates in stellar environment. Here we solved the RPA equations in deformed Nilsson basis, both in the particle particle (pp) and particle hole (ph) channels. Allowed beta decay and unique first-forbidden (U1F) rates were calculated in stellar matter. For certain cases, the calculated U1F contribution was much more than the allowed beta decay rates under prevailing stellar conditions in line with previous findings. Increasing temperature of the stellar core affected the allowed GT rates more than the U1F rates.

    Comments:
    26 pages 13 tables and zero figure
    Subjects:
    Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR)
    arXiv:
    2409.12565 [pdf]
    EPJA(2024)·0 citations
  6. 06

    [Submitted on 19 Sept 2024]

    Mode entanglement and isospin pairing in two-nucleon systems

    J Kovács🇭🇺 · A T Kruppa🇭🇺 · Ö Legeza🇭🇺 · P Salamon🇭🇺

    In this study, we explore the entanglement and correlation in two-nucleon systems using isospin formalism. With the help of Slater decomposition, we derive analytical expressions for various entanglement measures. Specifically, we analyse the one- and two-mode entropies, mutual informations, and a basis-independent characteristic known as the one-body entanglement entropy. To understand the impact of pairing, we consider interactions involving isovector and isoscalar L=0 pairing terms. Our findings show that certain pairing interactions can maximize one-body entanglement entropy of ground states when both total angular momentum and total isospin have zero projections. We provide numerical examples for the sd shell and explore the mutual informations in LS coupled and jj coupled single-particle bases. We find that the shell structure and angular momentum coupling significantly impact the measures of entanglement. We outline the implications of conserving angular momentum and isospin on one-mode entropies, irrespective of particle number.

    Comments:
    32 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2409.12583 [pdf]
    J.Phys.G(2025)·5 citations
  7. 07

    [Submitted on 19 Sept 2024]

    Detecting Hyperons in neutron stars -- a machine learning approach

    Valéria Carvalho🇵🇹 · Márcio Ferreira🇵🇹 · Constança Providência🇵🇹

    We present a neural network classification model for detecting the presence of hyperonic degrees of freedom in neutron stars. The models take radii and/or tidal deformabilities as input and give the probability for the presence of hyperons in the neutron star composition. Different numbers of observations and different levels of uncertainty in the neutron star properties are tested. The models have been trained on a dataset of well-calibrated microscopic equations of state of neutron star matter based on a relativistic mean-field formalism. Real data and data generated from a different description of hyperonic matter are used to test the performance of the models.

    Comments:
    15 pages, 8 figures, published version
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2409.12684 [pdf]
    PRD(2024)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE