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Nuclear Theory·nucl-th

Monday·March 21, 2022

9 papers—5 primary·4 cross-listed

All9Primary5Cross-lists4
  1. 01

    [Submitted on 18 Mar 2022]

    Neutron skin systematics from microscopic equations of state

    Francesca Sammarruca

    This paper presents an analysis of neutron skins based on fully microscopic equations of state, including chiral two- and three-nucleon forces consistently at N3LO. Other theoretical predictions and recent constraints are also addressed, such as those from the PREX II experiment and the latest parity-violating electron scattering measurement of the 27Al neutron skin.

    Comments:
    Revised version, to appear in Physical Review C
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2203.09753 [pdf]
    PRC(2022)·9 citations
  2. 02

    [Submitted on 18 Mar 2022]

    Spin Effects In Heavy Ion Collisions at High Energies

    Zuo-tang Liang🇨🇳

    In non-central high energy heavy ion collisions, the colliding system possesses a huge orbital angular momentum along the normal direction of the reaction plane. Due to the spin orbit interaction in the system, such a huge orbital angular momentum leads to the spin polarization of quarks and anti-quarks in the quark matter system produced in the collision. Such an effect, known as the global polarization effect, was predicted many years ago and has been confirmed by the STAR collaboration at RHIC. The discovery of the global polarization effect opens a new avenue in heavy ion physics in general and in studying the properties of quark-gluon plasma in particular. This talk will briefly review the original ideas and calculations that lead to the prediction and summarize progresses and problems in related aspects.

    Comments:
    plenary talk at the 24th International Spin Symposium (SPIN2021)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2203.09786 [pdf]
    JPS Conf.Proc.(2022)·5 citations
  3. 03

    [Submitted on 18 Mar 2022]

    decay and evolution of low-lying structure in Ge and As nuclei

    Kosuke Nomura

    A simultaneous calculation for the shape evolution and the related spectroscopic properties of the low-lying states, and the -decay properties in the even- and odd-mass Ge and As nuclei in the mass region, within the framework of the nuclear density functional theory and the particle-core coupling scheme, is presented. The constrained self-consistent mean-field calculations using a universal energy density functional (EDF) and a pairing interaction determines the interacting-boson Hamiltonian for the even-even core nuclei, and the essential ingredients of the particle-boson interactions for the odd-nucleon systems, and of the Gamow-Teller and Fermi transition operators. A rapid structural evolution from -soft oblate to prolate shapes, as well as the spherical-oblate shape coexistence around the neutron sub-shell closure , is suggested to occur in the even-even Ge nuclei. The predicted low-energy spectra, electromagnetic transition rates, and -decay values are in a reasonable agreement with experiment. The predicted values reflect the structures of the wave functions for the initial and final nuclei of decay, which are, to a large extent, determined by the microscopic input provided by the underlying EDF calculation.

    Comments:
    17 pages, 14 figures, 7 tables
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2203.09837 [pdf]
    PRC(2022)·13 citations
  4. 04

    [Submitted on 18 Mar 2022]

    Probing neutron-skin thickness with free spectator neutrons in ultracentral high-energy isobaric collisions

    Lu-Meng Liu🇨🇳 · Chun-Jian Zhang🇺🇸 · Jia Zhou🇨🇳 · Jun Xu🇨🇳 · Jiangyong Jia🇺🇸 · Guang-Xiong Peng🇨🇳

    We show that the yield ratio of free spectator neutrons produced in high-energy Zr+Zr to Ru+Ru collisions is a clean probe of the neutron-skin thickness of colliding nuclei and the slope parameter of the symmetry energy. The idea is demonstrated based on the proton and neutron density distributions via a state-of-the-art Skyrme-Hartree-Fock-Bogolyubov calculation. Among spectator nucleons given by the Glauber model, free spectator neutrons include those from direct production that survive from clusterization as well as those from deexcitation of heavy clusters described by the popular GEMINI model. More free neutrons are produced in collisions of Zr nucleus due to its larger neutron skin, compared to those produced in collisions of Ru nucleus with a smaller neutron skin. The difference of the free spectator neutron yield is further increased with the increasing difference of the neutron-skin thickness between Zr and Ru with a larger value, and the increase in ultracentral collisions is particularly insensitive to model details and experimental uncertainties. Since the production of free spectator neutrons is not affected by the complicated dynamics in the mid-rapidity region, the ratio of their multiplicities in ultracentral isobaric collisions is a robust observable for constraining the neutron skin and value.

    Comments:
    6 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex)
    arXiv:
    2203.09924 [pdf]
    PLB(2022)·39 citations
  5. 05

    [Submitted on 18 Mar 2022]

    Effects of two-body currents in the one-particle one-hole electromagnetic responses within a relativistic model

    T. Franco-Munoz · R. González-Jiménez · J.M. Udías

    Longitudinal () and transverse () responses from inclusive electron scattering from carbon 12 and calcium 40 nuclei are computed within a fully relativistic and unfactorized model for the initial and final states, and one- and two-body current operators leading to the one-particle one-hole responses. We find that the two-body contributions have no effect on but they increase by up to 30%, depending on the energy and momentum transfer. Inclusive cross sections have also been computed. In this case, the increase of due to two-body currents will translate into an increase in the cross-sections depending on the degree of transversity of each kinematic. The comparison with carbon data is good for the responses and the cross sections. In the case of calcium, while the model compares well with the cross section data, the agreement with the responses is generally poor. However, the inconsistencies between different data sets for the separate responses in this nucleus points to uncertainties underlying the procedure to extract the responses that are not considered (or largely underestimated) in the experimental error bars. Our calculation is fully relativistic and considers within the full quantum mechanical description both the initial and final nucleon states involved in the process. We also show that it is essential to go beyond the plane-wave approach, since incorporating the distortion of the nucleons while making the initial and final states orthogonal, allows to reproduce both the shape and magnitude of the cross section data and carbon responses. The good agreement with the electron scattering experimental data supports the use of this approach to describe the analogous neutrino-induced scattering reaction.

    Comments:
    21 pages, 8 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2203.09996 [pdf]
    J.Phys.G(2025)·22 citations

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first authorsco-authorsvia INSPIRE