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Nuclear Theory·nucl-th

Tuesday·February 16, 2021

12 papers—7 primary·5 cross-listed

All12Primary7Cross-lists5
  1. 01

    Hadronic resonance production and interaction in p-Pb collisions at LHC energies in EPOS3

    A. G. Knospe🇳🇱 · C. Markert🇺🇸 · K. Werner🇫🇷 · J. Steinheimer🇩🇪 · M. Bleicher🇩🇪

    Using the EPOS3 model with UrQMD to describe the hadronic phase, we study the production of short-lived hadronic resonances and the modification of their yields and spectra in p-Pb collisions at = 5.02 TeV. High-multiplicity p-Pb collisions exhibit similar behavior to mid-peripheral Pb-Pb collisions at LHC energies, and we find indications of a short-lived hadronic phase in p-Pb collisions that can modify resonance yields and spectra through scattering processes. The evolution of resonance production is investigated as a function of the system size, which is related to the lifetime of the hadronic phase, in order to study the onset of collective effects in p-Pb collisions. We also study hadron production separately in the core and corona parts of these collisions, and explore how this division affects the total particle yields as the system size increases.

    nucl-thnucl-exPRC(2021)·27 citations
  2. 02

    Thermodynamics of partonic matter in relativistic heavy-ion collisions from a multiphase transport model

    Han-Sheng Wang🇨🇳 · Guo-Liang Ma🇨🇳 · Zi-Wei Lin🇺🇸 · Wei-jie Fu🇨🇳

    Using the string melting version of a multiphase transport model, we focus on the evolution of thermodynamic properties of the central cell of parton matter produced in AuAu collisions ranging from 200 GeV down to 2.7 GeV. The temperature and chemical potentials have been calculated based on both Boltzmann and quantum statistics in order to locate their evolution trajectories in the QCD phase diagram. We demonstrate that the trajectories can depend on many physical factors, especially the finite nuclear thickness at lower energies. However, from the evolution of pressure anisotropy, only partial thermalization can be achieved when the partonic systems reach the predicted QCD phase boundary. It provides some helpful insights to studying the QCD phase structure through relativistic heavy-ion collisions.

    nucl-thhep-phnucl-exPRC(2022)·15 citations
  3. 03

    Configuration-interaction approach to nuclear fission

    G.F. Bertsch · K. Hagino

    We propose a configuration-interaction (CI) representation to calculate induced nuclear fission with explicit inclusion of nucleon-nucleon interactions in the Hamiltonian. The framework is designed for easy modeling of schematic interactions but still permits a straightforward extension to realistic ones. As a first application, the model is applied to branching ratios between fission and capture in the decay modes of excited fissile nuclei. The ratios are compared with the Bohr-Wheeler transition-state theory to explore its domain of validity. The Bohr-Wheeler theory assumes that the rates are insensitive to the final-state scission dynamics; the insensitivity is rather easily achieved in the CI parameterizations. The CI modeling is also capable of reproducing the branching ratios of the transition-state hypothesis which is one of the key ingredients in the present-day theory of induced fission.

    nucl-thphysics.atm-clusphysics.chem-ph1 citation
  4. 04

    Electron-positron vacuum instability in strong electric fields. Relativistic semiclassical approach

    D. N. Voskresensky🇷🇺

    Instability of electron-positron vacuum in strong electric fields is studied. First, falling to the Coulomb center is discussed at for a spinless boson and at for electron. Then, focus is concentrated on description of deep electron levels and spontaneous positron production in the field of a finite-size nucleus with the charge . Next, these effects are studied in application to the low-energy heavy-ion collisions. Then, we consider phenomenon of "electron condensation" on levels of upper continuum crossed the boundary of the lower continuum in the field of a supercharged nucleus with . Finally, attention is focused on many-particle problems of polarization of the QED vacuum and electron condensation at ultra-short distances from a source of charge. We argue for a principal difference of cases, when the size of the source is larger than the pole size , at which the dielectric permittivity of the vacuum reaches zero, and smaller . Some arguments are presented in favor of the logical consistency of QED. All problems are considered within the same relativistic semiclassical approach.

    nucl-thhep-phhep-thquant-phUniverse(2021)·19 citations
  5. 05

    Suppression of the nuclear rainbow in the inelastic nucleus-nucleus scattering

    Nguyen Hoang Phuc🇻🇳 · Dao T. Khoa🇻🇳 · Nguyen Tri Toan Phuc🇻🇳 · Do Cong Cuong🇻🇳

    The nuclear rainbow observed in the elastic -nucleus and light heavy-ion scattering is proven to be due to the refraction of the scattering wave by a deep, attractive real optical potential. The nuclear rainbow pattern, established as a broad oscillation of the Airy minima in the elastic cross section, originates from an interference of the refracted far-side scattering amplitudes. It is natural to expect a similar rainbow pattern also in the inelastic scattering of a nucleus-nucleus system that exhibits a pronounced rainbow pattern in the elastic channel. Although some feature of the nuclear rainbow in the inelastic nucleus-nucleus scattering was observed in experiment, the measured inelastic cross sections exhibit much weaker rainbow pattern, where the Airy oscillation is suppressed and smeared out. To investigate this effect, a novel method of the near-far decomposition of the inelastic scattering amplitude is proposed to explicitly reveal the coupled partial-wave contributions to the inelastic cross section. Using the new decomposition method, our coupled channel analysis of the elastic and inelastic C+C and O+C scattering at the refractive energies shows unambiguously that the suppression of the nuclear rainbow pattern in the inelastic scattering cross section is caused by a destructive interference of the partial waves of different multipoles. However, the inelastic scattering remains strongly refractive in these cases, where the far-side scattering is dominant at medium and large angles like that observed in the elastic scattering.

    nucl-thnucl-exEPJA(2021)·4 citations
  6. 06

    A new mass model for nuclear astrophysics: crossing 200 keV accuracy

    M. Shelley🇬🇧 · A. Pastore🇬🇧

    By using a machine learning algorithms, we present an improved nuclear mass table with a root mean square deviation of less than k̇eV. The model is equipped with statistical error bars in order to compare with available experimental data. We use the resulting model to predict the composition of the outer crust of a neutron star. By means of simple Monte Carlo methods, we propagate the statistical uncertainties of the mass model to the equation of state of the system.

    nucl-thnucl-exUniverse(2021)·25 citations
  7. 07

    Thermal evolution of relativistic hyperonic compact stars with calibrated equations of state

    Morgane Fortin🇵🇱 · Adriana R. Raduta🇷🇴 · Sidney Avancini🇧🇷 · Constanca Providencia🇵🇹

    A set of unified relativistic mean-field equations of state for hyperonic compact stars recently built in [M. Fortin, Ad. R. Raduta, S. Avancini, and C. Providencia, Phys. Rev. D {\bf 101}, 034017 (2020)] is used to study the thermal evolution of non-magnetized and non-rotating spherically-symmetric isolated and accreting neutron stars under different hypothesis concerning proton -wave superfluidity. These equations of state have been obtained in the following way: the slope of the symmetry energy is in agreement with experimental data; the coupling constants of and -hyperons are determined from experimental hypernuclear data; uncertainties in the nucleon- interaction potential are accounted for; current constraints on the lower bound of the maximum neutron star mass are satisfied. Within the considered set of equations of state, the presence of hyperons is essential for the description of the cooling/heating curves. One of the conclusions we reach is that the criterion of best agreement with observational data leads to different equations of states and proton -wave superfluidity gaps when applied separately for isolated neutron stars and accreting neutron stars in quiescence. This means that at least in one situation the traditional simulation framework that we employ is not complete and/or the equations of state are inappropriate. Another result is that, considering equations of state which do not allow for nucleonic dUrca or allow for it only in very massive NS, the low luminosity of SAX J1808 requires a repulsive -hyperon potential in symmetric nuclear matter in the range MeV. This range of values for is also supported by the criterion of best agreement with all available data from INS and XRT.

    nucl-thastro-ph.HEPRD(2021)·40 citations

Affiliations

first authorsco-authorsvia INSPIRE