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Nuclear Theory·nucl-th

Friday·June 17, 2022

9 papers—5 primary·4 cross-listed

All9Primary5Cross-lists4
  1. 01

    Driving Potential and Fission-Fragment Charge Distributions

    Yuan Su · Min Liu · Ning Wang

    We propose an efficient approach to describe the fission-fragment charge yields for actinides based on the driving potential of fissioning system. Considering the properties of primary fission fragments at their ground states, the driving potential, which represents the potential energies of the system around scission configuration and closely relates to the yields of fragments, can be unambiguously and quickly obtained from the Skyrme energy-density functional together with the Weizsaecker-Skyrme mass model. The fission-fragment charge distributions for thermal-neutroninduced fission and spontaneous fission of a series of actinides, especially the odd-even staggering in charge distributions can be well reproduced. Nuclear dynamical deformations and pairing corrections of fragments play an important role in the charge distributions.

    nucl-thCommun.Theor.Phys.(2022)·1 citation
  2. 02

    Incomplete absorption reactions at high energy

    Katsuhito Makiguchi🇯🇵 · Wataru Horiuchi🇯🇵

    The total reaction cross section of high-energy nucleus-nucleus collision refects the nuclear density profiles of the colliding nuclei and has been a standard tool to investigate the size properties of short-lived unstable nuclei. This basis relies on the assumption that the nucleus-nucleus collision is strongly absorptive in the sense of an optical model. However, this property does not hold completely, while incomplete absorption occurs when an overlap density of two colliding nuclei is low enough. In this paper, we propose a way to quantify this incompleteness, that is, the "blackness" of the total reaction cross section. A significance of this quantification is drawn by taking an example of the total reaction cross sections of proton-rich C isotopes.

    nucl-thPTEP(2022)·4 citations
  3. 03

    Spectral fluctuations in the interacting boson model

    Yu-Qing Wu · Wei Teng · Xiao-Jie Hou · Gui-Xiu · Yu Zhang · Bing-Cheng He · Yan-An Luo Na

    The energy dependence of the spectral fluctuations in the interacting boson model (IBM) and its connections to the mean-field structures have been analyzed through adopting two statistical measures, the nearest neighbor level spacing distribution measuring the chaoticity (regularity) in energy spectra and the statistics of Dyson and Metha measuring the spectral rigidity. Specifically, the statistical results as functions of the energy cutoff have been worked out for different dynamical situations including the U(5)-SU(3) and SU(3)-O(6) transitions as well as those near the AW arc of regularity. It is found that most of the changes in spectral fluctuations are triggered near the stationary points of the classical potential especially for the cases in the deformed region of the IBM phase diagram. The results thus justify the stationary point effects from the point of view of statistics. In addition, the approximate degeneracies in the spectrum on the AW arc is also revealed from the statistical calculations.

    nucl-thCPC(2022)·1 citation
  4. 04

    Influence of nuclear structure in relativistic heavy-ion collisions

    Yu-Gang Ma🇨🇳 · Song Zhang🇨🇳

    Many probes are proposed to determine the quark-gluon plasma and explore its properties in ultra-relativistic heavy-ion collisions. Some of them are related to initial states of the collisions, such as collective flow, Hanbury-Brown-Twiss (HBT) correlation, chiral magnetic effects and so on. The initial states can come from geometry overlap of the colliding nuclei, fluctuations or nuclear structure with the intrinsic geometry asymmetry. The initial geometry asymmetry can transfer to the final momentum distribution in the aspect of hydrodynamics during the evolution of the fireball. Different from traditional methods for nuclear structure study, the ultra-relativistic heavy-ion collisions could provide a potential platform to investigate nuclear structures with the help of the final-state observables after the fireball expansion. This chapter first presents a brief introduction of the initial states in relativistic heavy-ion collisions, and then delivers a mini-review for the nuclear structure effects on experimental observables in the relativistic energy domain.

    nucl-thnucl-ex24 citations
  5. 05

    Bayesian estimation of the low-energy constants up to fourth order in the nucleon-nucleon sector of chiral effective field theory

    Isak Svensson🇸🇪 · Andreas Ekström🇸🇪 · Christian Forssén🇸🇪

    We use Bayesian methods and Hamiltonian Monte Carlo (HMC) sampling to infer the posterior probability density function (PDF) for the low-energy constants (LECs) up to next-to-next-to-next- to-leading order (N3LO) in a chiral effective field theory (EFT) description of the nucleon-nucleon interaction. In a first step, we condition the inference on neutron-proton and proton-proton scattering data and account for uncorrelated EFT truncation errors. We demonstrate how to successfully sample the 31-dimensional space of LECs at N3LO using a revised HMC inference protocol. In a second step we extend the analysis by means of importance sampling and an empirical determination of the neutron-neutron scattering length to infer the posterior PDF for the leading charge-dependent contact LEC in the neutron-neutron interaction channel. While doing so we account for the EFT truncation error via a conjugate prior. We use the resulting posterior PDF to sample the posterior predictive distributions for the effective range parameters in the wave as well as the strengths of charge-symmetry breaking and charge-independence breaking. We conclude that empirical point-estimate results of isospin breaking in the channel are consistent with the PDFs obtained in our Bayesian analysis and that, when accounting for EFT truncation errors, one must go to next-to-next-to-leading order to confidently detect isospin breaking effects.

    nucl-thPRC(2023)·24 citations

Affiliations

first authorsco-authorsvia INSPIRE