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Nuclear Theory·nucl-th

Friday·January 17, 2020

12 papers—6 primary·6 cross-listed

All12Primary6Cross-lists6
  1. 01

    Can chiral EFT give us satisfaction?

    R. Machleidt🇺🇸 · F. Sammarruca🇺🇸

    We compare nuclear forces derived from chiral effective field theory (EFT) with those obtained from traditional (phenomenological and meson) models. By means of a careful analysis of paralleles and differences, we show that chiral EFT is superior to all earlier approaches in terms of both formal aspects and successful applications in ab initio calculations. However, in spite of the considerable progress made possible by chiral EFT, complete satisfaction cannot be claimed until outstanding problems---the renormalization issue being the most important one---are finally settled.

    nucl-thEPJA(2020)·32 citations
  2. 02

    An implementation of nuclear time-dependent density-functional theory and its application to the nuclear isovector electric dipole resonance

    Yue Shi · Nobuo Hinohara · Bastian Schuetrumpf

    Following a previous paper [Y. Shi, Phys. Rev. C 98, 014329(2018)], we present an extension of the density-functional theory to allow for dynamic calculations based on the obtained static Hartree-Fock results. We perform extensive benchmark calculations, by comparing the calculated results with that of an existing code Sky3D. To perform linear-response calculations using the TDDFT method, comparisons have been made with the finite-amplitude quasiparticle random-phase approximation (FAM-QRPA) method. We plan to apply the TDDFT method to a systematic description of the IVD resonances in the Zr, Mo, and Ru isotopes. The strengths of IVD resonances are calculated using two complementary methods: TDDFT and FAM-QRPA methods. For the TDDFT results, additional benchmark calculations have been performed using the well-tested code Sky3D. In these three models, the important ingredients which have major influence on the results, such as time-odd potentials, boundary conditions, smoothing procedures, spurious peaks etc., have been carefully examined. The current TDDFT and the Sky3D codes yield almost identical response functions once both codes use the same time-odd mean fields and absorbing boundary conditions. The strengths of the IVD resonances calculated using the TDDFT and FAM-QRPA methods agree reasonably well with the same position of the giant dipole resonance. Upon seeing a reasonable accuracy offered by the implemented code, we perform systematic TDDFT calculations for spherical Zr and Mo isotopes near , where experimental data exist. For neutron-rich Zr, Mo, and Ru isotopes where shape evolution exist we predict the photoabsorption cross sections based on oblate and triaxial minima.

    nucl-thPRC(2020)·9 citations
  5. 05

    The Early Stages of Heavy Ion Collisions

    Francois Gelis🇫🇷

    Heavy ion collisions pose interesting challenges to quantum chromodynamics, because they probe the parton structure of the incoming nuclei at very small longitudinal momentum fractions. Combined with the large size of nuclei, this may lead to the phenomenon of gluon saturation. The Color Glass Condensate is an effective QCD description that aims to cope with such a situation. In this talk, I show how one may study heavy ion collisions in this framework.

    nucl-thhep-phPoS(2020)·0 citations
  6. 06

    Quantified limits of the nuclear landscape

    Léo Neufcourt · Yuchen Cao · Samuel A. Giuliani · Witold Nazarewicz · Erik Olsen · Oleg B. Tarasov

    The chart of the nuclides is limited by particle drip lines beyond which nuclear stability to proton or neutron emission is lost. Predicting the range of particle-bound isotopes poses an appreciable challenge for nuclear theory as it involves extreme extrapolations of nuclear masses beyond the regions where experimental information is available. Still, quantified extrapolations are crucial for a variety of applications, including the modeling of stellar nucleosynthesis. We use microscopic nuclear mass models and Bayesian methodology to provide quantified predictions of proton and neutron separation energies as well as Bayesian probabilities of existence throughout the nuclear landscape all the way to the particle drip lines. We apply nuclear density functional theory with several energy density functionals. To account for uncertainties, Bayesian Gaussian processes are trained on the separation-energy residuals for each individual model, and the resulting predictions are combined via Bayesian model averaging. This framework allows to account for systematic and statistical uncertainties and propagate them to extrapolative predictions. We characterize the drip-line regions where the probability that the nucleus is particle-bound decreases from to . In these regions, we provide quantified predictions for one- and two-nucleon separation energies. According to our Bayesian model averaging analysis, 7759 nuclei with have a probability of existence . The extrapolations obtained in this study will be put through stringent tests when new experimental information on exotic nuclei becomes available. In this respect, the quantified landscape of nuclear existence obtained in this study should be viewed as a dynamical prediction that will be fine-tuned when new experimental information and improved global mass models become available.

    nucl-thnucl-exstat.MLPRC(2020)·112 citations
  7. 07

    Boost-invariant description of polarization within hydrodynamics with spin

    Rajeev Singh🇵🇱

    We briefly review a recently proposed formalism of perfect-fluid hydrodynamics with spin, which is a generalization of the standard hydrodynamic framework and provides a natural tool for describing the evolution of spin-polarized systems of particles with spin 1/2. It is based on the de Groot - van Leeuwen - van Weert forms of energy-momentum and spin tensors and conservation laws. Using Bjorken symmetry we show how this formalism may be used to determine observables describing the polarization of particles measured in the experiment.

    ↳ hep-phnucl-thActa Phys.Polon.Supp.(2020)·4 citations
  8. 08

    Population synthesis of helium white dwarf--red giant star mergers and the formation of lithium-rich giants and carbon stars

    Xianfei Zhang · C.Simon Jeffery · Yaguang Li · Shaolan Bi

    The formation histories of lithium-rich and carbon-rich red giants are not yet understood. It has been proposed that the merger of a helium-core white dwarf with a red giant branch star might provide a solution. We have computed an extended grid of post-merger evolution models and combined these with predictions of binary star population synthesis. The results strongly support the proposal that the merger of a helium white dwarf with a red giant branch star can provide the progenitors of both lithium-rich red clump stars and early-R carbon stars. The distribution of post-merger models in , , , the surface abundances of lithium and carbon, and the predicted space densities agree well with the observed distributions of these parameters for Li-rich and early-R stars in the Galaxy.

    ↳ astro-ph.SRnucl-thApJ(2020)·3 citations
  11. 11

    Inclusive spectra and Bose-Einstein correlations in small thermal quantum systems

    M.D. Adzhymambetov🇺🇦 · Yu.M. Sinyukov🇺🇦

    The spectra and correlation of identical particles emitted from small local-equilibrium sources are considered. The size of the system is defined by the negative part of the parabolic falling chemical potential. The analytical solution of the problem is found for the case of inclusive measurements. It is shown that in the case where the size of the system is comparable to the thermal wavelength of the particles, the spectra and correlation functions are far from the quasiclassical approximation expected for large systems, and observed femtoscopy scales (interferometry radii) will be essentially smaller than the Gaussian radii of the source. If the maximum value of the chemical potential approaches the critical one, specific for the system, one can consider the possibility of the Bose-Einstein condensation. In such a case the reduction of the intercept of the correlation function for inclusive measurements takes place. The results can be used for the searching of femtoscopy homogeneity lengths in proton-proton collisions at LHC energies.

    ↳ hep-phnucl-thPRD(2020)·1 citation
  12. 12

    Triangle Singularities and Charmonium-like States

    Feng-Kun Guo🇨🇳

    The spectrum of hadrons is important for understanding the confinement of quantum chromodynamics. Many new puzzles arose since 2003 due to the abundance of experimental discoveries with the structures in the heavy quarkonium mass region being the outstanding examples. Hadronic resonances correspond to poles of the -matrix, which has other types of singularities such as the triangle singularity due to the simultaneous on-shellness of three intermediate particles. Here we briefly discuss a few possible manifestations of triangle singularities in the physics, paying particular attention to the formalism that can be used to analyze the data for charged structures in the distributions of the reaction .

    ↳ hep-phhep-exnucl-thNucl.Phys.Rev.(2020)·18 citations

Affiliations

first authorsco-authorsvia INSPIRE