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Nuclear Theory·nucl-th

Thursday·August 15, 2024

11 papers—6 primary·5 cross-listed

All11Primary6Cross-lists5
  1. 01

    [Submitted on 13 Aug 2024]

    Study of the Log-third-difference method for the computation of even-odd staggering in fission yields

    Belén Montenegro Viñas · Manuel Caamaño

    The even-odd staggering in fission fragments yield distributions is an important observable to address the role of intrinsic excitations in the fission process. However, its computation as a function of the fragment split is an ill-posed problem that is usually solved through certain assumptions. Arguably, the most widely used method for its computation is the Log-third-difference method, which assumes an underlying local Gaussian distribution. Experimental data of the even-odd effect show sharp features and peaks that are a challenge for the Log-third difference method (or any method for that matter). This paper presents a detailed study of the performance of the Log-third difference method and describes three strategies for improving the precision and accuracy around these sharp features. The best results are obtained with an iterative application of the method and with the use of a multi-Gaussian fit. In regions with a smooth behaviour, the direct application of the Log-third-difference method remains the best option.

    Comments:
    15 pages, 13 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2408.07173 [pdf]
    EPJA(2024)·0 citations
  2. 02

    [Submitted on 14 Aug 2024]

    Pions valence quark distributions in asymmetric nuclear matter at finite temperature

    Satyajit Puhan🇮🇳 · Navpreet Kaur🇮🇳 · Arvind Kumar🇮🇳 · Suneel Dutt🇮🇳 · Harleen Dahiya🇮🇳

    We have calculated the valence quark distributions of the lightest pseudoscalar meson, pions, in the isospin asymmetric nuclear matter at zero and finite temperature employing a light-cone quark model. The medium modifications in the pion properties have been stimulated through the effective quark masses computed using the chiral SU() quark mean field model. We have primarily focused on the impact of isospin asymmetric medium on the distribution amplitudes (DAs) and parton distribution functions (PDFs) of a valence quark for different baryon density and temperature values. Also, the DAs and PDFs have been evolved to GeV and GeV for different densities of nuclear medium and results have been compared with the available experimental data. The DAs and PDFs are found to modify substantially as a function of baryon density as compared to temperature and isospin asymmetry of the medium.

    Comments:
    26 pages and 10 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2408.07334 [pdf]
    PRD(2024)·15 citations
  3. 03

    [Submitted on 14 Aug 2024]

    Survival Probabilities of Compound Superheavy Nuclei Towards Element 119

    Yu Qiang · Xiang-Quan Deng · Yue Shi · C.Y. Qiao · Junchen Pei

    To synthesize superheavy element 119 is becoming highly concerned as several experimental projects in major laboratories are being pursued. This work studied the survival probabilities of compound superheavy nuclei after multiple neutron emissions based on microscopic energy dependent fission barriers, demonstrating a significant role of triaxial deformation in decreasing the first fission barriers in the heaviest region. Together with the fusion cross sections by the dinuclear system model, the optimal energy and the residual cross section of Am(Ca, 3)Mc are reproduced. Finally the cross sections and optimal beam energies of Am+Cr and Bk+Ti reactions are estimated, providing clues for the synthesis of new elements.

    Comments:
    5 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2408.07371 [pdf]
    PLB(2024)·3 citations
  4. 04

    [Submitted on 14 Aug 2024]

    Quantum Entanglement in Nuclear Fission

    Yu Qiang · Junchen Pei · Kyle Godbey

    Nuclear fission presents a unique example of quantum entanglement in strongly interacting many-body systems. A heavy nucleus can split into hundreds of combinations of two complementary fragments in the fission process. The entanglement of fragment wave functions is persistent even after separation and impacts the partition of particles and energies between fragments. Based on microscopic dynamical calculations of the fission of Pu, this work finds that quantum entanglement is indispensable in the appearance of sawtooth distributions of average excitation energies of fragments and thus neutron multiplicities, but not in average neuron excess of fragments. Both sawtooth slopes from particle-number projections are found to be steep -- a feature which can be alleviated by random fluctuations. These findings may impact the understanding of quantum entanglement more broadly in mesoscopic systems.

    Comments:
    11 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2408.07375 [pdf]
    PLB(2025)·17 citations
  5. 05

    [Submitted on 14 Aug 2024]

    Anti-flow of Mesons in the High Baryon Density Region

    Zuo-Wen Liu🇨🇳 · Shusu Shi🇨🇳

    The E895 and STAR experiments demonstrate that the slopes of directed flow with respect to rapidity () of mesons are negative in the low transverse momentum () region, GeV/, in Au + Au collisions at GeV. Using the transport model JAM, we investigate the directed flow of , , and as functions of rapidity, , and collision energy in Au + Au collisions at the same energies as those in the E895 and STAR experiments. We find that the JAM model can qualitatively reproduce the anti-flow of observed in the E895 experiment. The slopes of pions and kaons are analyzed as functions of the window, revealing a strong dependence of the slopes. Negative slopes are observed in the low region, GeV/, while positive slopes are shown in the higher region. We find that the shadowing effect from spectators is crucial in generating the anti-flow of mesons at low in the high baryon density region.

    Comments:
    7 pages, 7 figures, accepted by Phys. Rev. C
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2408.07563 [pdf]
    PRC(2024)·6 citations
  6. 06

    [Submitted on 14 Aug 2024]

    A study of bound states of , , , , and mesons with light and heavy nuclei within chiral SU(3) model

    Arvind Kumar🇮🇳 · Amruta Mishra🇮🇳

    In the present work we explore the possibilities of the formation of bound states of neutral pseudoscalar mesons , and and the vector meson , with the nuclei C, O, Ca and Pb, calculating their binding energy and absorption decay width. To calculate the optical potentials of these mesons in different nuclei under study, we shall use the chiral SU(3) hadronic mean field model, in which the properties of nucleons in the medium are modified through the scalar isoscalar fields and and the scalar-isovector field . The scalar-isovector field account for the finite isospin asymmetry of different nuclei having asymmetry in number of protons and neutrons. The binding energy and absorption decay width of mesons are calculated for the ground state and some of possible excited states of the nuclei. In the chiral SU(3) model, the mesons , and are observed to have significant negative mass shift upto nuclear saturation density which lead to the possibility of the bound states at least for ground states and some of excited states in case of heavy nuclei. For the pseudoscalar singlet and the vector meson the mass shift obtained are found to be small and bound states are not formed. The present calculations are compared with different studies available in the field and will be useful in understanding the outcomes from different experimental facilities focusing on this area of research.

    Comments:
    40 pages, 11 figures, Accepted for publication in Chinese Physics C
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2408.07633 [pdf]
    CPC(2025)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE