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Nuclear Theory·nucl-th

Monday·February 5, 2024

7 papers—6 primary·1 cross-listed

All7Primary6Cross-lists1
  1. 01

    [Submitted on 2 Feb 2024]

    Nakanishi integral representation of pseudoscalar fermion-antifermion bound states in the Bethe--Salpeter equation

    Shaoyang Jia🇺🇸

    We propose a method to solve for the pseudoscalar bound state amplitude of a fermion and an antifermion from its Bethe--Salpeter equation (BSE) in the Minkowski space applying spectral representations. With the dressing of the fermion propagators specified by their spectral functions, we first derive the explicit expressions for the Nakanishi spectral functions of the Bethe--Salpeter wave function (BSWF) in terms of these propagators and the Bethe--Salpeter amplitude (BSA) directly from the definition in the momentum space. Applying the rainbow-ladder truncation in the covariant gauge, we then convert the BSE in the momentum space into identities that calculate the spectral functions of the BSA from those of the gauge-boson propagator and of the BSWF. These relations form a closed set of linear functionals for the Nakanishi spectral functions with analytical kernels, laying the foundation for the numerical solution of the BSE in the Minkowski space.

    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Theory (hep-th)
    arXiv:
    2402.01125 [pdf]
    1 citation
  2. 02

    [Submitted on 2 Feb 2024]

    Constraining theoretical Corrections to Gamow-Teller Transition Rates

    L. Xayavong · Y. Lim

    We propose two novel constraints for the theoretical corrections to Gamow-Teller transition rates. The first, derived from a two-level model, predicts forbidden regions within the plane defined by the isospin-mixing correction, , and the ratio, , of the isospin-symmetry Gamow-Teller matrix elements between the upper and lower admixed states. It serves as a filter for the theoretical calculations, particularly effective for small values of . The other employs experimental values, incorporating the upper admixed states, and exploits mirror symmetry to eliminate isospin-invariant and nuclear structure-independent quantities. This approach not only offers an alternative mean for collectively testing theoretical corrections but also, as a byproduct, enables the extraction of . This provides another sensitive test for the isospin-conserving component of nuclear Hamiltonian. Our investigation reveals a substantial cancellation of among radiative correction contributions in these tests.

    Comments:
    6 pages, 1 supplementary material, 2 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2402.01165 [pdf]
    PRC(2025)·2 citations
  3. 03

    [Submitted on 2 Feb 2024]

    Residual Tensor Force Effects on the Gamow-Teller states in Magic Nuclei, 48Ca, 90Zr, 132Sn, and 208Pb

    Eunja Ha · Myung-Ki Cheoun · H. Sagawa

    We investigate the tensor force (TF) effect %in the residual interaction on the Gamow-Teller (GT) transitions in four magic nuclei, Ca, Zr, Sn and Pb. The TF is taken into account by using the Brückner -matrix theory with the charge-dependent (CD) Bonn potential as the residual interaction of charge-exchange quasiparticle random phase approximation (QRPA). We found that particle-particle () tensor interaction does not affect the GT transitions because of the closed shell nature in the nuclei, but repulsive particle-hole () residual interaction for the configuration of spin-orbit partners dominates the high-lying giant GT states for all of the nuclei. It is also shown that appreciable GT strengths are shifted to lower energy region by the attractive TF for the same configuration, and produce the low-lying GT peak about 2.5 MeV in Ca. Simultaneously, in Zr and Sn, the low-energy strength appears as a lower energy shoulder near the main GT peak. On the other hand, the shift of the low-lying GT state is not seen clearly for Pb because of the strong spin-orbit splitting of high orbits, which dominates the GT strength.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2402.01184 [pdf]
    PTEP(2024)·1 citation
  4. 04

    [Submitted on 2 Feb 2024]

    Production of hypernuclei from antiproton capture within a relativistic transport model

    Alexander Schmidt🇩🇪 · Theodoros Gaitanos🇬🇷 · Alexandre Obertelli🇩🇪 · José-Luis Rodríguez-Sánchez🇪🇸

    Production yields of single- hypernuclei from simulated peripheral annihilations of antiprotons after capture on various target nuclei are reported. The initial annihilation process and the production of excited hypernuclei are estimated within the GiBUU transport framework, while their deexcitation process is treated with the ABLA++ code. The yield of excited hypernuclei range from 0.3% for O to 1.2% for Xe per annihilation, consistent with previous measurements at LEAR, CERN. The yield of specific ground state hypernuclei after deexcitation reaches up to a few 10 per annihilation. The hypernuclei are produced in strangeness exchange reactions occuring between a nucleon of the target and the kaons originating from the annihilation in 80% of the cases, while the strangeness pair production in secondary pion-nucleon collision contributes to the remaining 20%. The simulations indicate that antiproton annihilations at rest on different nuclei could populate a wide range of so-far unexplored hypernuclei.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2402.01351 [pdf]
    EPJA(2024)·2 citations
  5. 05

    [Submitted on 2 Feb 2024]

    Relativistic Dissipative Magnetohydrodynamics from the Boltzmann equation for a two-component gas

    Khwahish Kushwah🇧🇷 · Gabriel S. Denicol🇧🇷

    We derive the equations of motion of relativistic magnetohydrodynamics, as well as microscopic expressions for all of its transport coefficients, from the Boltzmann equation using the method of moments. In contrast to reference Phys. Rev. D 98(7) 2018, where a single component gas was considered, we perform our derivation for a locally neutral fluid composed of two massless particle species with opposite charges. We demonstrate that the magnetohydrodynamical equations of motion become dramatically different for this more realistic system. The shear-stress tensor no longer obeys a single differential equation; it breaks into three non-degenerate components with respect to the magnetic field, each evolving according to different dynamical equations. For large magnetic fields, we further show that the solution of this theory displays oscillatory behaviour that can no longer be described by an Israel-Stewart-like theory. Finally, we investigate the derived equations in a Bjorken flow scenario.

    Comments:
    18 pages, 12 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2402.01597 [pdf]
    PRD(2024)·14 citations
  6. 06

    [Submitted on 2 Feb 2024]

    Solving coupled Non-linear Schrödinger Equations via Quantum Imaginary Time Evolution

    Yang Hong Li🇬🇧 · Jim Al-Khalili🇬🇧 · Paul Stevenson🇬🇧

    Coupled non-linear Schrödinger equations are crucial in describing dynamics of many particle systems. We present a quantum imaginary time evolution (ITE) algorithm as a solution to such equations in the case of nuclear Hartree-Fock equations. Under a simplified Skyrme interaction model, we calculate the ground state energy of an oxygen-16 nucleus and demonstrate that the result is in agreement with the classical ITE algorithm.

    Subjects:
    Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2402.01623 [pdf]
    Eur.Phys.J.ST(2025)·1 citation

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first authorsco-authorsvia INSPIRE