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Nuclear Theory·nucl-th

Tuesday·December 14, 2021

12 papers—6 primary·6 cross-listed

All12Primary6Cross-lists6
  1. 01

    [Submitted on 10 Dec 2021]

    Symmetries of the nucleon-nucleon -matrix and effective field theory expansions

    Silas R. Beane🇺🇸 · Roland C. Farrell🇺🇸

    The s-wave nucleon-nucleon (NN) scattering matrix (-matrix) exhibits UV/IR symmetries which are hidden in the effective field theory (EFT) action and scattering amplitudes, and which explain some generic features of the phase shifts. These symmetries offer clarifying interpretations of existing pionless EFT expansions, and suggest starting points for novel expansions. The leading-order (LO) -matrix obtained in the pionless EFT with scattering lengths treated exactly is shown to have a UV/IR symmetry which leaves the sum of s-wave phase shifts invariant. A new scheme, which treats effective range corrections exactly, and which possesses a distinct UV/IR symmetry at LO, is developed up to NLO (next-to-LO) and compared with data.

    Comments:
    20 pages, 4 figures. Contribution to Special Issue of Few-Body Systems: Celebrating 30 years of Steven Weinberg's papers on Nuclear Forces from Chiral Lagrangians. References and clarifications added in v2
    Subjects:
    Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2112.05800 [pdf]
    Few Body Syst.(2022)·20 citations
  2. 02

    [Submitted on 11 Dec 2021]

    Influence of collective nuclear vibrations on initial state eccentricities in Pb+Pb collisions

    B.G. Zakharov🇷🇺

    We study within the Monte Carlo Glauber model the influence of collective quantum effects in the Pb nucleus on the azimuthal anisotropy coefficients in Pb+Pb collisions at the LHC energies. To account for the quantum effects, we modify the sampling of the nucleon positions by applying suitable filters that guarantee that the colliding nuclei have the mean squared quadrupole and octupole moments consistent with the ones extracted from the experimental quadrupole and octupole strength functions for the Pb nucleus with the help of the energy weighted sum rule. Our Monte Carlo Glauber model with the modified sampling of the nucleon positions leads to at centrality \%, which allows to resolve the -to- puzzle.

    Comments:
    13 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2112.06066 [pdf]
    J.Exp.Theor.Phys.(2022)·4 citations
  3. 03

    [Submitted on 12 Dec 2021]

    Isovector density and isospin impurity in

    H. Sagawa · S. Yoshida · T. Naito · T. Uesaka · J. Zenihiro · J. Tanaka · T. Suzuki

    We study isoscalar (IS) and isovector (IV) densities in in comparison with theoretical densities calculated by Skyrme Hartree-Fock (HF) models. The charge symmetry breaking and the charge independence breaking forces are introduced to study the effect on the IV density. The effect of isospin mixing in the ground-state density is examined by using the particle-vibration coupling model taking into account the collective IV giant monopole excitation. We show a clear correlations in the IV density and isospin impurity of within the HF and the particle-vibration coupling model. We extract for the first time the experimental information of isospin impurity from the magnitude of IV density.

    Comments:
    6 pages, 7 figures, 1 table for main text; 4 pages, 7 figures, 2 tables for supplemental materials
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2112.06169 [pdf]
    PLB(2022)·10 citations
  4. 04

    [Submitted on 13 Dec 2021]

    Weinberg Operator Contribution to the Hadronic CP Violation

    Nodoka Yamanaka🇯🇵

    The CP violating Weinberg operator (or the gluon chromo-electric dipole moment) is generated in many candidates of new physics beyond the standard model, and it contributes to observables such as the electric dipole moments (EDM) of the neutron, nuclei and atoms. In this proceedings contribution, we review the present understanding of the Weinberg operator as well as the result of the estimation of its effect to the EDM of He nucleus through the contact CP-odd nuclear force.

    Comments:
    5 pages, 2 figures, proceedings of the 24th International Spin Symposium (SPIN2021), Matsue, Japan, October 2021
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2112.06478 [pdf]
    JPS Conf.Proc.(2022)·2 citations
  5. 05

    [Submitted on 13 Dec 2021]

    Shape coexistence and neutron skin thickness of Pb isotopes by the deformed relativistic Hartree-Bogoliubov theory in continuum

    Seonghyun Kim · Myeong-Hwan Mun · Myung-Ki Cheoun · Eunja Ha

    We investigate ground states properties of Pb isotopes located between neutron and proton drip-lines estimated by two-neutron (two-proton) separation energies and Fermi energies within the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc). First, we report some candidates of nuclear shape coexistence in the isotope chain. They are accessed by calculating total energy as a function of the deformation parameter , and for the coexistence candidates we take a couple of the deformation region bringing about minima of the energy within energy difference 1 MeV. Second, the Pb isotopes near neutron drip-lines are also investigated and compared to the results by other nuclear mass models. We find out eleven neutron emitters, Pb, giving rise to the Pb peninsular near the neutron drip-line. Finally, by exploiting the neutron and proton density we deduce the neutron skin thickness (NST) of the Pb isotopes and compare to the available experimental data. The recent data regarding the shape coexistence of Pb and the NST of Pb are shown to be well matched with the present results.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2112.06520 [pdf]
    PRC(2022)·41 citations
  6. 06

    [Submitted on 13 Dec 2021]

    Single-Nucleon Energies Changing with Nucleon Number

    J. P. Schiffer · B. P. Kay · J. chen

    The broad range of accumulated experimental data on the binding energies for single-particle states in nuclei is examined as a function of the constituent number of neutrons and protons and an unexpectedly simple pattern emerges. The dependence of the energies of neutron states on the number of constituent protons, or of proton states on the number of neutrons, are very similar to each other and the sign reflects the well-known strong attraction. For the same kind of nucleons changing as in the state -- energies for neutron states with neutron number changing or proton states with protons -- the dependence is at least a factor of four weaker in magnitude and slightly repulsive, except when the changing nucleons are only within the same orbit as the state. The systematics of the accumulated data are presented with a minimum of use made of model assumptions.

    Comments:
    5 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2112.06740 [pdf]
    0 citations

Affiliations

first authorsco-authorsvia INSPIRE