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Nuclear Theory·nucl-th

Wednesday·April 17, 2024

3 papers—1 primary·2 cross-listed

All3Primary1Cross-lists2
  1. 01

    [Submitted on 16 Apr 2024]

    Prediction of Nuclear Charge Density Distribution with Feedback Neural Network

    Tian-Shuai Shang · Jian Li · Zhong-Ming Niu

    The nuclear charge density distribution plays an important role in nuclear physics and atomic physics. As one of the most frequently used models to obtain charge density distribution, the two-parameter fermi (2pF) model has been widely applied in both nuclear physics and atomic physics. Currently, the feedforward neural network has been employed to study the available 2pF model parameters for 86 nuclei, and it is found that by introducing A^{1/3} into the input parameter of the neural network, the accuracy and precision of the parameter learning effect are improved. Furthermore, the average result of multiple predictions is more reliable than the best result of a single prediction, and there is no significant difference between the average result of density value and of parameter value for the average charge density distribution. In addition, 2pF parameters of 284 (near) stable nuclei are also predicted in this work, which provides a reference for the experiment.

    Comments:
    11 pages, 8 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2404.10585 [pdf]
    Nucl.Sci.Tech.(2022)·36 citations
  2. 02

    [Submitted on 15 Apr 2024] (cross-list from physics.optics)

    Multi-photon stimulated grasers assisted by laser-plasma interactions

    C.-J. Yang · K. M. Spohr · D. Doria

    We investigate theoretically the possibility of achieving the stimulated amplification of -rays. Herein, our approach circumvents the so-called ``graser dilemma" through a non-linear, multi-photon mechanism. Our work foresees the combination of a high-intensity flash generated by the interaction of a high-intensity laser pulse with plasma and intensive photons supplied by an additional laser. We show that multi-photon stimulated emission processes can have a larger effective cross-section compared to a one-photon process. The bandwidth of the supplied photons can also be tuned to curtail linewidth broadening. Naturally, Mossbauer transitions can be chosen to apply the scheme in the first instance. Furthermore, we derive that even multi-photon stimulated emission in the form of an anti-Stokes type could allow our scheme to be applied to non-Mossbauer nuclei, provided that the supplied photon energy can be tuned to compensate for the recoil and other broadening induced losses. The graser development can be spearheaded using multi-PW class high-power laser systems such as the 10 PW installation at Extreme Light Infrastructure - Nuclear Physics (ELI-NP) in Romania.

    Comments:
    13 pages, 5 figures
    Subjects:
    physics.optics (physics.optics); Nuclear Theory (nucl-th); Plasma Physics (physics.plasm-ph); Quantum Physics (quant-ph)
    arXiv:
    2404.10025 [pdf]
    3 citations
  3. 03

    [Submitted on 15 Apr 2024] (cross-list from hep-ph)

    Chiral phase transition in soft-wall AdS/QCD with scalar-dilaton coupling

    Sean P. Bartz🇺🇸 · Robert C. Meadows🇺🇸 · Glenn Brock🇺🇸

    The chiral phase boundary of nuclear matter is expected to have a critical point where the rapid crossover of lattice methods at zero chemical potential becomes a first-order phase transition. Phenomenological models based on the AdS/CFT correspondence, known as AdS/ QCD, have succeeded in capturing many features of nuclear matter, with recent progress in producing the expected critical point. We study a model that produces a critical point in the chiral phase diagram by introducing a coupling between the scalar chiral field and the dilaton. We examine the effect of the scalar-dilaton coupling on the critical point. We also study the zero-temperature chiral dynamics, which must allow for spontaneous chiral symmetry breaking in the limit of zero quark mass. We find that when the scalar-dilaton coupling is large enough to ensure correct zero-temperature chiral dynamics, a critical point is present only if the quark mass is greater than 12.8 MeV.

    Comments:
    18 pages, 9 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2404.10104 [pdf]
    PRD(2024)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE