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Nuclear Theory·nucl-th

Friday·October 7, 2022

11 papers—7 primary·4 cross-listed

All11Primary7Cross-lists4
  1. 01

    Bayesian probability updates using Sampling/Importance Resampling: Applications in nuclear theory

    Weiguang Jiang · Christian Forssén

    We review an established Bayesian sampling method called sampling/importance resampling and highlight situations in nuclear theory when it can be particularly useful. To this end we both analyse a toy problem and demonstrate realistic applications of importance resampling to infer the posterior distribution for parameters of NNLO interaction model based on chiral effective field theory and to estimate the posterior probability distribution of target observables. The limitation of the method is also showcased in extreme situations where importance resampling breaks.

    nucl-thFront.in Phys.(2022)·12 citations
  2. 02

    Proposal for a Nuclear Light Source

    E. V. Tkalya · P. V. Borisyuk · M. S. Domashenko · Yu. Yu. Lebedinskii

    The paper considers a principal possibility of creating a nuclear light source of the vacuum ultra violet (VUV) range based on the Th nucleus. This nuclear light source can help to solve two main problems -- excitation of the low-lying Th isomer and precision measurement of the nuclear isomeric transition energy. The Thorium nuclear light source is based on the nuclei implanted in a thin dielectric film with a large bandgap. While passing an electric current through the sample, the Th nuclei are excited to the low energy isomeric state eV) in the process of inelastic scattering of conduction electrons. The subsequent spontaneous decay of Th is followed by the emission of quanta in the VUV range. The luminosity of the Thorium nuclear light source is approximately ~photons/s per 1~A of current and per 1~ng of Th. The suggested scheme to obtain radiation from the Th isomer can be considered as a kind of nuclear analogue of the optical radiation from the usual metal-insulator-semiconductor (MIS) junction.

    nucl-thCPC(2023)·3 citations
  3. 03

    Nuclear symmetry energy and the PREX-CREX neutron skin puzzle within the KIDS framework

    Panagiota Papakonstantinou

    I briefly review the KIDS theoretical framework for the nuclear equation of state (EoS) and energy density functional (EDF), I discuss recent results for the curvature parameter of the symmetry energy, and I address the PREX-CREX puzzle. I show that it is possible to obtain EDF models which can reproduce both PREX-II and CREX results each within its respective error bars. Such EDFs correspond to EoSs which soften towards low densities, as could be attributed to clusterization. Before such a scenario is considered viable, the dipole polarizability should also be examined.

    nucl-thNucl.Theor.(2022)·14 citations
  4. 04

    Effect of isovector scalar meson on equation of state of dense matter within relativistic mean field model

    Virender Thakur🇮🇳 · Raj Kumar🇮🇳 · Pankaj Kumar🇮🇳 · Vikesh Kumar🇮🇳 · Mukul Kumar🇮🇳 · C. Mondal🇫🇷 · B.K. Agrawal🇮🇳 · Shashi K. Dhiman🇮🇳

    The effects of the isovector-scalar -meson field on the properties of finite nuclei, infinite nuclear matter and neutron stars are investigated within the Relativistic Mean Field (RMF) model which includes non-linear couplings. Several parameter sets (SRV's) are generated to asses the influence of -meson on the properties of neutron star. These parametrizations correspond to different values of coupling constant of -meson to the nucleons with remaining ones calibrated to yield finite nuclei and infinite nuclear matter properties consistent with the available experimental data. It is observed that to fit the properties of finite nuclei and infinite nuclear matter, a stronger coupling between isovector-vector meson and nucleons is required in the presence of field. Furthermore, the -meson is found to affect the radius of canonical neutron star significantly. The value of dimensionless tidal deformability, for the canonical neutron star also satisfies the constraints from the waveform models analysis of GW170817 binary neutron star merger event. A covariance analysis is performed to estimate the statistical uncertainties of the model parameters as well as correlations among the model parameters and different observables of interest.

    nucl-thPRC(2022)·33 citations
  5. 05

    Single- & double-strangeness hypernuclei up to within chiral effective field theory

    H. Le🇩🇪

    We investigate and hypernuclei with employing the Jacobi-NCSM approach and in combination with baryon-baryon interactions derived within the frame work of chiral effective field theory. The employed interactions are transformed using the similarity renormalization group (SRG) so that the low- and high-momentum states are decoupled, and, thereby,convergence of the binding energies with respect to model space can be significantly speeded up. Such an evolution is however only approximately unitary when the so-called SRG induced higher-body forces are omitted. We first explore the impact of the SRG evolution on the separation energies in hypernuclei when only SRG-evolved two-body and when both two- and three-body forces are included. For the latter scenario, we thoroughly study predictions of the two almost phase-equivalent NLO13 and NLO19 YN potentials for hypernuclei. The NLO19 interaction yields separation energies that are comparable with experiment, whereas NLO13 underestimates all the systems considered. We further explore CSB splittings in the multiplets employing the two NLO YN potentials that include also the leading CSB potential in the N channel, whose strength has been fitted to the presently established CSB in . Finally, we report on our recent study for hypernuclei based on the N interaction at NLO.

    nucl-thEPJ Web Conf.(2022)·3 citations
  6. 06

    Nuclear binding energies in artificial neural networks

    Lin-Xing Zeng · Yu-Ying Yin · Xiao-Xu Dong · Li-Sheng Geng

    The binding energy (BE) or mass is one of the most fundamental properties of an atomic nucleus. Precise binding energies are vital inputs for many nuclear physics and nuclear astrophysics studies. However, due to the complexity of atomic nuclei and of the non-perturbative strong interaction, up to now, no conventional physical model can describe nuclear binding energies with a precision below 0.1 MeV, the accuracy needed by nuclear astrophysical studies. In this work, artificial neural networks (ANNs), the so called ``universal approximators", are used to calculate nuclear binding energies. We show that the ANN can describe all the nuclei in AME2020 with a root-mean-square deviation (RMSD) around 0.2 MeV, which is better than the best macroscopic-microscopic models, such as FRDM and WS4. The success of the ANN is mainly due to the proper and essential input features we identify, which contain the most relevant physical information, i.e., shell, paring, and isospin-asymmetry effects. We show that the well-trained ANN has excellent extrapolation ability and can predict binding energies for those nuclei so far inaccessible experimentally. In particular, we highlight the important role played by ``feature engineering'' for physical systems where data are relatively scarce, such as nuclear binding energies.

    nucl-thnucl-exPRC(2024)·20 citations
  7. 07

    Microscopic nucleus-nucleus optical potentials from nuclear matter with uncertainty analysis from chiral forces

    T. R. Whitehead

    Nucleus-nucleus optical potentials are constructed from an energy density functional approach first outlined by Brueckner et al. The interaction term of the energy density functional comes from the complex nucleon self-energy computed in nuclear matter with two- and three-body chiral nuclear forces. Nuclear density distributions are calculated from Skyrme functionals constrained to the equations of state calculated from the same chiral forces used for the self-energy. Predictions for elastic scattering cross sections and fusion cross sections are compared to experimental data. Very good agreement is found with experiment for elastic scattering of heavier nucleus-nucleus systems at energies in the range of MeV/N, while accurate descriptions of lighter and lower-energy systems may require the inclusion of collective excitations.

    nucl-th1 citation

Affiliations

first authorsco-authorsvia INSPIRE