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Nuclear Theory·nucl-th

Wednesday·July 17, 2024

7 papers—6 primary·1 cross-listed

All7Primary6Cross-lists1
  1. 01

    [Submitted on 15 Jul 2024]

    Multipole responses in fissioning nuclei and their uncertainties

    Tong Li · Nicolas Schunck · Mike Grosskopf

    Electromagnetic multipole responses are key inputs to model the structure, decay and reaction of atomic nuclei. With the introduction of the finite amplitude method (FAM), large-scale calculations of the nuclear linear response in heavy deformed nuclei have become possible. This work provides a detailed study of multipole responses in actinide nuclei with Skyrme energy density functionals. We quantify both systematic and statistical uncertainties induced by the functional parameterization in FAM calculations. We also extend the FAM formalism to perform blocking calculations with the equal filling approximation for odd-mass and odd-odd nuclei, and analyze the impact of blocking configurations on the response. By examining the entire plutonium isotopic chain from the proton to the neutron dripline, we find a large variability of the response with the neutron number and study how it correlates with the deformation of the nuclear ground state.

    Comments:
    26 pages with 5-page supplemental material, 15 figures in the main text and 8 figures in the supplemental material
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2407.11097 [pdf]
    PRC(2024)·5 citations
  2. 02

    [Submitted on 15 Jul 2024]

    Spin correlation in two-proton emission from Be

    Tomohiro Oishi

    This paper presents a theoretical evaluation of spin correlation in the two-proton () radioactive emission. The three-body model of Be with the proton-proton interaction, which is adjusted to reproduce the experimental energy release, is utilized. Time-dependent calculation is performed to compute the coupled-spin state of the emitted two protons. The spin-correlation function as the Clauser-Horne-Shimony-Holt (CHSH) indicator is evaluated as . Namely, the -spin correlation beyond the limit of local-hidden-variable (LHV) theory is suggested. This correlation is sensitive to the proton-proton interaction. The short-lived (broad-width) ~state has the weaker spin correlation. In parallel, the core-proton interactions do not harm this correlation during the time-dependent decaying process. The CHSH measurement can be a novel probe into the effective nuclear interaction inside finite systems. Two-proton emitters can provide a testing field for identical-particle entanglement.

    Comments:
    4 figures, 1 table. Title is slightly changed. Accepted in Physics Letters B
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); Quantum Physics (quant-ph)
    arXiv:
    2407.11136 [pdf]
    PLB(2025)·3 citations
  3. 03

    [Submitted on 15 Jul 2024]

    Neutron stars and the dense matter equation of state: from microscopic theory to macroscopic observations

    Katerina Chatziioannou🇺🇸 · H. Thankful Cromartie🇺🇸 · Stefano Gandolfi🇺🇸 · Ingo Tews🇺🇸 · David Radice🇺🇸 · Andrew W. Steiner🇺🇸 · Anna L. Watts🇳🇱

    The past years have witnessed tremendous progress in understanding the properties of neutron stars and of the dense matter in their cores, made possible by electromagnetic observations of neutron stars and the detection of gravitational waves from their mergers. These observations provided novel constraints on neutron-star structure, that is intimately related to the properties of dense neutron-rich matter described by the nuclear equation of state. Nevertheless, constraining the equation of state over the wide range of densities probed by astrophysical observations is still challenging, as the physics involved is very broad and the system spans many orders of magnitude in densities. Here, we review theoretical approaches to calculate and model the neutron-star equation of state in various regimes of densities, and discuss the related consequent properties of neutron stars. We describe how the equation of state can be calculated from nuclear interactions that are constrained and benchmarked by nuclear experiments. We review neutron-star observations, with particular emphasis on information provided by gravitational-wave signals and electromagnetic observations. Finally, we discuss future challenges and opportunities in the field.

    Comments:
    55 pages, 26 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
    arXiv:
    2407.11153 [pdf]
    RMP(2025)·107 citations
  4. 04

    [Submitted on 16 Jul 2024]

    Proton drip line of deformed hypernuclei

    Yi-Xiu Liu🇨🇳 · Huai-Tong Xue🇨🇳 · Q. B. Chen🇨🇳 · Xian-Rong Zhou🇨🇳 · H.-J. Schulze🇮🇹

    The proton drip line of (hyper)nuclei is examined within the framework of the deformed Skyrme-Hartree Fock approach by adjusting the nuclear force parameters to exactly reproduce the core binding energies. The impact of adding a {\Lambda} hyperon in a s or p state is studied, and it is found that in some cases the deformation effect facilitates the extension of the drip line by an added p-state hyperon. However, no extension of the drip line is found for s-state hypernuclei.

    Comments:
    7 pages, 2 Figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2407.11312 [pdf]
    PRC(2025)·1 citation
  5. 05

    [Submitted on 16 Jul 2024]

    The first-order phase transition in the neutron star from the deep neural network

    Wenjie Zhou · Hong Shen · Jinniu Hu · Ying Zhang

    This study investigates the first-order phase transition within neutron stars, leveraging the deep neural network (DNN) framework alongside contemporary astronomical measurements. The equation of state (EOS) for neutron stars is delineated in a piecewise polytropic form, with the speed of sound () serving as a pivotal determinant. In the phase transition region, is presumed to be zero, while in other intervals, it is optimized utilizing the DNN. Various onset energy densities of phase transition (), spanning from to (where denotes the energy density at nuclear saturation density), as well as phase transition widths () ranging from to , are examined. Our findings underscore that smaller values of lead to a more substantial impact of on neutron star properties, encompassing maximum mass, corresponding radius, tidal deformability, phase transition mass, and trace anomaly. Conversely, when exceeds , the influence of diminishes, resulting in a stiffer EOS compared to scenarios lacking a phase transition. Furthermore, the trace anomaly at high density shifts to negative values upon the commencement of the phase transition. It is noteworthy that the correlations between the average speed of sound at different energy density segments demonstrate a notably weak connection. The discernment of whether a phase transition has occurred with the present observables of neutron stars poses a challenging task.

    Comments:
    23 pages, 9 figures, 3 tables, accepted by Physical Review D
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2407.11447 [pdf]
    PRD(2024)·12 citations
  7. 07

    [Submitted on 16 Jul 2024] (cross-list from hep-ph)

    New physical processes for extracting GPDs with a better sensitivity to partonic structure

    Jian-Wei Qiu🇺🇸 · Zhite Yu🇺🇸

    We introduce a new type of exclusive processes for a better study of generalized parton distributions (GPDs), which we refer to as single-diffractive hard exclusive processes (SDHEPs). We advocate a two-stage framework for picturing SDHEPs based on the separation of scales, which gives a clear description both kinematically and dynamically. We examine the sensitivity of the SDHEP to the parton momentum fraction -dependence of GPDs, and demonstrate it quantitatively with two specific processes that can be readily measured at J-PARC or AMBER using a pion beam and at JLab using a photon beam, respectively. Both processes are capable of providing enhanced sensitivity to the -dependence, overcoming the problem of shadow GPDs, and disentangling different types of GPDs with various spin asymmetries.

    Comments:
    5 pages, 2 figures; contributed talk to DIS2024
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2407.11304 [pdf]
    PoS(2025)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE