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Nuclear Theory·nucl-th

Monday·June 17, 2024

9 papers—7 primary·2 cross-listed

All9Primary7Cross-lists2
  1. 01

    [Submitted on 14 Jun 2024]

    Spontaneous fission half-life in Fm isotopes with nuclear energy density functional

    Kouhei Washiyama

    A microscopic description of fission dynamics is important to understand the decay properties of neutron-rich heavy nuclei that are relevant to -process nucleosynthesis. To provide a reliable and efficient method to evaluate the spontaneous fission half-life, we develop a method, called the constrained Hartree--Fock--Bogoliubov (CHFB) plus local quasiparticle random-phase approximation (LQRPA), to include dynamical residual effects in the collective inertia. With the CHFB + LQRPA, we evaluate the collective potential and the collective inertia along a mass-symmetric fission path in Fm isotopes with the neutron numbers --164. The obtained LQRPA inertia is much larger than the cranking one that ignores dynamical residual effects and shows a remarkable variation along the fission path. We estimate the fission half-life of the Fm isotopes using the action integral with the obtained collective potential and inertia. A large difference between the fission half-lives obtained with the LQRPA inertia and with the cranking inertia is observed. This indicates the importance of evaluating the collective inertia for estimating the fission half-life.

    Comments:
    5 pages, 6 figures, to be published in the proceedings of FUSION23
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2406.09735 [pdf]
    EPJ Web Conf.(2024)·0 citations
  2. 02

    [Submitted on 14 Jun 2024]

    Exploration on halo nucleus C from D-RHFB structure to reaction observables

    Jia-Lin An · Qi Lu · Wen Hui Long · Shi-Sheng Zhang

    We utilize the axially deformed relativistic Hartree-Fock-Bogoliubov (D-RHFB) model to describe the structure of neutron-rich carbon isotopes, taking into account the continuum, pairing correlations, tensor force and their interplay. In this scheme, one- and two-neutron separation energies of neutron-rich carbon isotopes agree well with measured data, as well as the spin and parity for the ground state of C, which is a long-standing problem for theoretical structure models. With the structure input extracted from the microscopic D-RHFB model, the reaction observables are well described the Glauber model. In particular, this unified approach accurately reproduces the inclusive longitudinal momentum distributions of the breakup reaction C + C at 240 MeV/nucleon, which rule out the possibility of the ground state of C being . Moreover, the continuum plays a crucial role in the formation of the halo, which is further confirmed by the reaction cross sections and longitudinal momentum distributions. However, the tensor force components carried by the -coupling are not as significant as anticipated. Consequently, the D-RHFB + Glauber approach turns out to be a promising tool to search for halo candidates from the structure to the reaction.

    Comments:
    The description on the reactions on the carbon target needs more works
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2406.09766 [pdf]
    J.Phys.G(2025)·3 citations
  3. 03

    [Submitted on 14 Jun 2024]

    Triaxial shape of the one-proton emitter Lu

    Qi Lu · Kai-Yuan Zhang · Shi-Sheng Zhang

    We revisit the proton emitter Lu utilizing the recently developed triaxial relativistic Hartree-Bogoliubov theory in continuum (TRHBc). By incorporating the microscopic nuclear structure properties from the TRHBc theory into the WKB approximation, we successfully reproduce the measured proton-emission half-life of Lu within experimental uncertainties. A triaxial ground state characterized by () has been clarified for Lu. The inclusion of triaxiality significantly changes nuclear density distributions and potentials, which results in enhanced binding of both the nuclear system and the proton-emitting orbital. As a result, a slightly extended half-life for the proton emission of Lu is achieved after considering triaxial deformation degrees of freedom.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2406.09803 [pdf]
    PLB(2024)·18 citations
  4. 04

    [Submitted on 14 Jun 2024]

    The weak magnetic field effect on dilepton polarization in heavy-ion collisions

    Minghua Wei🇨🇳 · Li Yan🇨🇳

    The measurement of the magnetic field created in high-energy heavy-ion collisions is challenging, due the the fact that the magnetic field decays so drastically that in a thermalized quark-gluon plasma the field strength becomes rather weak. By incorporating the weak magnetic effect into the medium, and especially into the production formalism of dileptons from the quark-gluon plasma, the effect of dilepton polarization is studied through the dilepton angular distribution. We find that the anisotropic coefficients in the dilepton spectrum are quite sensitive to the orientation and strength of the weak field. Accordingly, these coefficients provide ideal probes for the magnetic field in realistic experiments.

    Comments:
    13 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2406.10041 [pdf]
    PRD(2024)·8 citations
  5. 05

    [Submitted on 14 Jun 2024]

    Weak entanglement approximation for nuclear structure

    Oliver C. Gorton · Calvin W. Johnson

    The interacting shell model, a configuration-interaction method, is a venerable approach for low-lying nuclear structure calculations; but it is hampered by the exponential growth of its basis dimension as one increases the single-particle space and/or the number of active particles. Recent, quantum-information-inspired work has demonstrated that the proton and neutron sectors of a nuclear wave function are weakly entangled. Furthermore, the entanglement is smaller for nuclides away from , such as heavy, neutron-rich nuclides. Here we implement a weak entanglement approximation to bipartite configuration-interaction wave functions, approximating low-lying levels by coupling a relatively small number of many-proton and many-neutron states. This truncation scheme, which we present in the context of past approaches, reduces the basis dimension by many orders of magnitude while preserving essential features of nuclear spectra.

    Comments:
    11 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2406.10120 [pdf]
    PRC(2024)·26 citations
  6. 06

    [Submitted on 14 Jun 2024]

    Investigating the Role of Quantum Entanglement in Heavy Ion Collisions through Elliptic Flow

    Mira Varma🇺🇸 · Oliver Baker🇺🇸

    This paper investigates the relationship between initial spatial anisotropy and final state momentum anisotropy in heavy ion collisions through the analysis of elliptic flow () as a function of transverse momentum (). Building upon previous studies on thermalization in heavy ion collisions using transverse momentum distributions, we extend the analysis to the dependence of in Pb-Pb and Xe-Xe collisions. By employing a two-component model to extract the thermal and hard scattering contributions to the elliptic flow, we aim to gain further insights into the role of quantum entanglement in the rapid thermalization and collective behavior of the quark-gluon plasma (QGP).

    Comments:
    The arXiv version of this paper incorporates additional theoretical context about quantum entanglement in heavy ion collisions based on recent literature. The core contribution is our systematic measurement and analysis of the two-component behavior in elliptic flow across different centralities in Xe-Xe and Pb-Pb collisions. A revised version of this work has been prepared for journal submission
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Quantum Physics (quant-ph)
    arXiv:
    2406.10129 [pdf]
    1 citation
  7. 07

    [Submitted on 14 Jun 2024]

    Study of the Coulomb and nuclear breakup of Be using a Halo-EFT description at NLO

    L.-P. Kubushishi · P. Capel

    Background: The halo effective field theory (Halo-EFT) provides a very efficient description of loosely-bound nuclei in models of reaction. It offers a very systematical ranking of the significance of nuclear-structure observables in reaction calculations. This greatly helps to infer reliable structure information from reaction cross sections. However, for a meaningful analysis, the Halo-EFT scheme needs to have converged. Purpose: In a previous study [P. Capel, D. R. Phillips, and H.-W. Hammer, Phys. Rev. C 98, 034610 (2018)], NLO descriptions of 11Be have been developed and lead to excellent agreement with existing breakup data. However, the convergence of the scheme at NLO was not fully demonstrated. Moreover, a significant dependence on the regulator of the effective 10Be-n interaction has been observed. Method: We develop Halo-EFT descriptions of 11Be at N2LO and use them in an accurate breakup-reaction code. We compare our theoretical cross sections with experiment on Pb and C targets at about 70 MeV/nucleon. Results: On Pb, the N2LO descriptions of 11Be lead to little change to the NLO results of the previous study, confirming the convergence of that scheme. On C, the reaction is significantly affected by the presence of d resonances in the low-energy spectrum of 11Be. In the Halo-EFT power counting these resonances appear only at N2LO; our new descriptions include them naturally. Going to N2LO removes also the cutoff dependence observed in the previous study. Conclusions: We demonstrate the convergence of the Halo-EFT description of 11Be at NLO for Coulomb breakup and at N2LO for nuclear-dominated dissociation. The reliability of the nuclear-structure information inferred in the previous study is thus confirmed.

    Comments:
    9 pages, 7 figures - This work has been accepted for publication in Physical Review C
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2406.10168 [pdf]
    PRC(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE