Nuclear Theory·nucl-th

Friday·June 17, 2022

9 papers—5 primary·4 cross-listed

01
[Submitted on 16 Jun 2022]
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.
Comments:
to appear in Comm. Theor. Phys
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2206.07858 [pdf]
Commun.Theor.Phys.(2022)·1 citation
02
[Submitted on 16 Jun 2022]
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.
Comments:
14 pages, 5 figures, to appear in Prog. Theor. Exp. Phys
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2206.07939 [pdf]
PTEP(2022)·4 citations
03
[Submitted on 16 Jun 2022]
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 $P (S)$ measuring the chaoticity (regularity) in energy spectra and the $Δ_{3} (L)$ 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 $2^{+}$ spectrum on the AW arc is also revealed from the statistical calculations.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2206.07947 [pdf]
CPC(2022)·1 citation
04
[Submitted on 16 Jun 2022]
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.
Comments:
28 pages, 21 figures; contribution to the "Handbook of Nuclear Physics", Springer, 2022, edited by I. Tanihata, H. Toki, and T. Kajino
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2206.08218 [pdf]
24 citations
05
[Submitted on 16 Jun 2022]
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 ( $χ$ 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 $χ$ 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 $^{1} S_{0}$ neutron-neutron interaction channel. While doing so we account for the $χ$ 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 $^{1} S_{0}$ 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 $^{1} S_{0}$ channel are consistent with the PDFs obtained in our Bayesian analysis and that, when accounting for $χ$ EFT truncation errors, one must go to next-to-next-to-leading order to confidently detect isospin breaking effects.
Comments:
17 pages, 9 figures. One additional figure in the ancillary material. Updated to match the Phys Rev C version as closely as possible
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2206.08250 [pdf]
PRC(2023)·24 citations
06
[Submitted on 15 Jun 2022] (cross-list from gr-qc)
Dynamical evolution of fermion-boson stars with realistic equations of state
Joseph E. Nyhan🇺🇸 · Ben Kain🇺🇸
Fermion-boson stars are mixtures of the ordinary nuclear matter of a neutron star and bosonic dark matter. We dynamically evolve fermion-boson stars for the first time using a realistic equation of state for nuclear matter. We use our dynamical solutions to make a detailed study of the evolution of weakly and strongly perturbed static solutions. As examples of our findings, we identify a region of parameter space where weakly perturbed unstable static solutions migrate to a stable configuration and we determine the criteria under which strongly perturbed stable static solutions will always move to a stable configuration instead of collapsing to a black hole.
Comments:
12 pages, 6 figures. arXiv admin note: text overlap with arXiv:2201.02274
Subjects:
General Relativity and Quantum Cosmology (gr-qc); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2206.07715 [pdf]
PRD(2022)·17 citations
07
[Submitted on 16 Jun 2022] (cross-list from hep-ph)
Inverse Primakoff Scattering for Axionlike Particle Coupling
C.-P. Wu🇨🇦 · C.-P. Liu🇹🇼 · Greeshma C.🇮🇳 · L. Singh🇮🇳 · J.-W. Chen🇹🇼 · H.-C. Chi🇹🇼 · M.K. Pandey🇹🇼 · H.T. Wong🇹🇼
Axionlike particles (ALPs) can be produced in the Sun, and are considered viable candidates for the cosmological dark matter (DM). It can decay into two photons or interact with matter. We identify new inelastic channels of inverse Primakoff processes due to atomic excitation and ionization. Their cross sections are derived by incorporating full electromagnetic fields of atomic charge and current densities, and computed by well-benchmarked atomic many-body methods. Complementing data from the underground XENONnT and surface TEXONO experiments are analyzed. Event rates and sensitivity reaches are evaluated with respect to solar- and DM-ALPs. New parameter space in ALP couplings with the photons versus ALP masses in (1~eV $-$ 10~keV) not previously accessible to laboratory experiments are probed and excluded with solar-ALPs. However, at regions where DM-ALPs have already decayed, there would be no ALP-flux and hence no interactions at the detectors in direct search experiments. No physics constraints can be derived. Future projects would be able to evade the stability bound and open new observable windows in (100~eV $-$ 1~MeV) for DM-ALPs.
Comments:
1 table, 12 figures, V2 Published Version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2206.07878 [pdf]
PRD(2023)·9 citations
08
[Submitted on 16 Jun 2022] (cross-list from nucl-ex)
Re-investigation of the interplay of fission modes and non-equilibrium fission processes in heavy actinide nuclei 249Bk and 257Md
R. Dubey🇵🇱 · G. Kaur🇫🇷 · Abhishek Yadav🇮🇳 · N. Saneesh🇮🇳 · Akhil Jhingan🇮🇳 · P. Sugathan🇮🇳 · Tathagata Banerjee🇮🇹 · K.S. Golda🇮🇳 · Hardev Singh🇮🇳 · Meenu Thakur🇮🇳 · Ruchi Mahajan🇺🇸
Measurements of mass and angular distributions of fission fragments from actinide nuclei 249Bk and 257Md, produced in fusion reactions 11B and 19F + 238238U, are presented. Experimentally observed mass ratio distributions indicate 'multi-chance fission' through the interplay of fission modes in the fission process, and they agree well with predictions from calculations using the GEF ('GEneral description of Fission observables') model code. Furthermore, to test the signatures of events from non-compound nuclear processes in the fission of 249Bk and 257Md nuclei, Monte Carlo statistical decay model calculations using GEMINI++ were performed for the measured mass distribution at all energies. For comparison purposes, the fission fragment mass distributions of neighboring heavy actinide nuclei, previously measured in the fission of 250Cf and 254Fm nuclei produced by 12C and 16O projectiles on a 238U target, are also presented. The measured angular anisotropy data for the 19F + 238U reaction differ from the results of the Transition State Model at energies below the fusion barrier. As a result of the present study, we suggest considering the interplay between K relaxation time, dynamic dissipation, and their influence on shell correction to understand the evolution of fission dynamics in heavy-ion-induced actinide nuclei
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2206.07903 [pdf]
PLB(2024)·1 citation
09
[Submitted on 16 Jun 2022] (cross-list from astro-ph.HE)
Properties of pasta phases in catalyzed neutron stars
H. Dinh Thi🇫🇷 · A. F. Fantina🇫🇷 · F. Gulminelli🇫🇷
Exotic non-spherical configurations of nuclei, known as ``pasta" phases, are expected to be present at the bottom of the inner crust of a neutron star. We study the properties of these configurations in catalyzed neutron stars within a compressible liquid-drop model approach, with surface parameters optimized to reproduce experimental nuclear masses. Our results show that the properties of the pasta phases exhibit strong model dependence. To estimate the model uncertainties, a Bayesian analysis is performed, combining information from nuclear physics experiments and chiral perturbation theoretical calculations with astrophysical observations. The inferred posterior distributions are discussed, with particular focus on the effect of the low-density energy functional on the predictions.
Comments:
Proceedings of the International Workshop on Multi-facets of EOS and Clustering 2021; published in Il Nuovo Cimento C
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2206.07969 [pdf]
Nuovo Cim.C(2022)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE