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Nuclear Theory·nucl-th

Friday·June 23, 2023

9 papers—4 primary·5 cross-listed

All9Primary4Cross-lists5
  1. 01

    Nuclear structure and elastic scattering observables obtained consistently with different NN interactions

    R.B. Baker · M. Burrows · Ch. Elster · P. Maris · G. Popa · S.P. Weppner

    Nucleon-nucleon () interactions based on chiral effective theories are commonly used in ab initio calculations of light nuclei. Here we present a study based on three different NN interactions (up to next-to-next-to-leading order) for which structure and elastic proton scattering observables are consistently calculated for He, C, and O. The interactions are compared at the two-body level in terms of Wolfenstein amplitudes, and their predictions for ground state energies, point-proton radii, and charge form factors, as well as proton elastic scattering observables in the leading-order spectator expansion in the energy range between 65 and 160 MeV projectile energy are presented. To gain further insight into differences visible in elastic scattering observables, we investigate the behavior of the calculated effective nucleon-nucleus interactions for the C nucleus based on the different interactions.

    nucl-thnucl-exPRC(2023)·5 citations
  2. 02

    Efficient solver of relativistic hydrodynamics with implicit Runge-Kutta method

    Nathan Touroux🇯🇵 · Masakiyo Kitazawa🇯🇵 · Koichi Murase🇯🇵 · Marlene Nahrgang🇫🇷

    We propose a new method to solve the relativistic hydrodynamic equations based on implicit Runge-Kutta methods with a locally optimized fixed-point iterative solver. For numerical demonstration, we implement our idea for ideal hydrodynamics using the one-stage Gauss-Legendre method as an implicit method. The accuracy and computational cost of our new method are compared with those of explicit ones for the (1+1)-dimensional Riemann problem, as well as the (2+1)-dimensional Gubser flow and event-by-event initial conditions for heavy-ion collisions generated by TrENTo. We demonstrate that the solver converges with only one iteration in most cases, and as a result, the implicit method requires a smaller computational cost than the explicit one at the same accuracy in these cases, while it may not converge with an unrealistically large . By showing a relationship between the one-stage Gauss-Legendre method with the iterative solver and the two-step Adams-Bashforth method, we argue that our method benefits from both the stability of the former and the efficiency of the latter.

    nucl-thhep-phphysics.comp-phphysics.flu-dynPTEP(2024)·1 citation
  3. 03

    Detailed study of the astrophysical direct capture reaction in a potential model approach

    E.M. Tursunov · S.A. Turakulov · K.I. Tursunmakhatov

    The astrophysical factor and reaction rates of the direct capture process Li(p,Be are estimated within a two-body single-channel potential model approach. Central potentials of the Gaussian-form in the and waves are adjusted to reproduce the binding energies and the empirical values of the asymptotic normalization coefficients (ANC) for the Be(3/2) ground and Be(1/2) excited bound states, respectively. The parameters of the potential in the most important scattering channel were fitted to reproduce the empirical phase shifts from the literature and the low-energy astrophysical factor of the LUNA collaboration. The obtained results for the astrophysical factor and the reaction rates are in a very good agreement with available experimental data sets. The numerical estimates reproduce not only the absolute values, but also the energy and temperature dependence of the factor and reaction rates of the LUNA collaboration, respectively. The estimated primordial abundance ratio is well consistent with recent BBN result of after the Planck observation.

    nucl-thastro-ph.SRPRC(2023)·7 citations
  4. 04

    Generative modeling of nucleon-nucleon interactions

    Pengsheng Wen · Jeremy W. Holt · Maggie Li

    Developing high-precision models of the nuclear force and propagating the associated uncertainties in quantum many-body calculations of nuclei and nuclear matter remain key challenges for ab initio nuclear theory. In the present work we demonstrate that generative machine learning models can construct novel instances of the nucleon-nucleon interaction when trained on existing potentials from the literature. In particular, we train the generative model on nucleon-nucleon potentials derived at second and third order in chiral effective field theory and at three different choices of the resolution scale. We then show that the model can be used to generate samples of the nucleon-nucleon potential drawn from a continuous distribution in the resolution scale parameter space. The generated potentials are shown to produce high-quality nucleon-nucleon scattering phase shifts. This work provides an important step toward a comprehensive estimation of theoretical uncertainties in nuclear many-body calculations that arise from the arbitrary choice of nuclear interaction and resolution scale. Source code for this project can be found at https://github.com/pswen2019/Glow-nuclear-potential.git.

    nucl-thPRL(2024)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE