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Nuclear Theory·nucl-th

Monday·December 25, 2023

10 papers—4 primary·6 cross-listed

All10Primary4Cross-lists6
  1. 01

    [Submitted on 22 Dec 2023]

    Pairing effects on pure rotational energy of nuclei

    K. Abe · H. Nakada

    By applying the angular-momentum projection (AMP) to the self-consistent axial mean-field solutions with the semi-realistic effective Hamiltonian M3Y-P6, the pairing effects on the pure rotational energy of nuclei, \textit{i.e.}, the rotational energy at a fixed intrinsic state, have been investigated. While it was shown at the Hartree-Fock (HF) level that the individual terms of the Hamiltonian contribute to the rotational energy with ratios insensitive to nuclides except for light or weakly-deformed nuclei, the pair correlations significantly change the contributions, even for the well-deformed heavy nuclei. The contribution of the interaction to the rotational energy is found to correlate well with the degree of proximity between nucleons, which is measured via the expectation value that two nucleons exist at the same position. While the nucleons slightly spread as the angular momentum increases at the HF level, accounting for the positive (negative) contribution of the attractive (repulsive) components of the interaction, the pair correlations reduce or invert the effect.

    Comments:
    29 pages including 16 figures; submitted to JPG
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2312.14347 [pdf]
    J.Phys.G(2024)·1 citation
  2. 02

    [Submitted on 22 Dec 2023]

    Systematic study of the rotational bands in the mass region

    Anshul Dadwal · Xiao-Tao He

    For the first time, we conducted a comprehensive analysis of the rotational bands in the \( A\sim250 \) mass region. Utilizing a variety of rotational energy models and formulas, we have extracted free parameters for 36 rotational bands within this mass region, encompassing neutron numbers from N = 148 to 152. A significant enhancement has been made to the vibrational distortion model, leading to an exceptional match with the experimental data on dynamic moment of inertia across most of the rotational bands studied. Through the application of this revised model, we have categorized the dynamic moment of inertia into three distinct groups. The implications of the modified vibrational distortion term and how it evolves with changes in rotational frequency is also investigated. Our systematic investigation brings to light the peculiar behavior of Pu isotopes, especially in ground state bands of \( ^{242,244}\text{Pu}\), within this mass region. We provide a thorough discussion on various aspects such as the role of shape-fluctuation energy, the softness parameter, band-head and average moment of inertia, the prominence of the anti-pairing effect, and the transition from pairing to anti-pairing effects in Pu isotopes. Moreover, these findings are compared with other isotones, offering a comprehensive understanding of their unique characteristics.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2312.14386 [pdf]
    0 citations
  3. 03

    [Submitted on 22 Dec 2023]

    Entanglement in few-nucleon scattering events

    Tanja Kirchner · Wael Elkamhawy · Hans-Werner Hammer

    We investigate the spin entanglement in few-nucleon scattering processes involving nucleons and deuterons. For this purpose, we consider the entanglement power introduced by Beane et al. We analyze different entanglement entropies as a basis to define the entanglement power of the strong interaction and calculate the corresponding entanglement powers for proton-neutron, neutron-deuteron, proton-deuteron, and deuteron-deuteron scattering. For the latter two processes, we also take into account the modification from the Coulomb interaction. In contrast to proton-neutron scattering, no universal low-energy features are evident in the spin entanglement in neutron-deuteron, proton-deuteron, and deuteron-deuteron scattering.

    Comments:
    16 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2312.14484 [pdf]
    Few Body Syst.(2024)·26 citations
  4. 04

    [Submitted on 22 Dec 2023]

    Can we observe effects of early nonequilibrium dynamics using collective flow

    Piotr Bozek

    The rapid expansion of the fireball created in a heavy-ion collision causes strong departures from local equilibrium. Such effects are especially important in the very early phase of the collision, bringing a substantial pressure asymmetry. We investigate effects of this early stage pressure asymmetry in a kinetic model without boost-invariance. In the kinetic evolution the pressure asymmetry results from the competition of the longitudinal expansion and the kinetic relaxation. Unlike the transverse flow, the directed flow is found to be very sensitive to the equilibration rate and the pressure anisotropy.

    Comments:
    Proceedings for Quark Matter 2023, Houston, USA
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2312.14641 [pdf]
    EPJ Web Conf.(2024)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE