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Nuclear Theory·nucl-th

Tuesday·February 25, 2020

10 papers—7 primary·3 cross-listed

All10Primary7Cross-lists3
  1. 01

    Three-Nucleon Forces: Implementation and Applications to Atomic Nuclei and Dense Matter

    Kai Hebeler🇩🇪

    Recent advances in nuclear structure theory have significantly enlarged the accessible part of the nuclear landscape via ab initio many-body calculations. These developments open new ways for microscopic studies of light, medium-mass and heavy nuclei as well as nuclear matter and represent an important step toward a systematic and comprehensive understanding of atomic nuclei across the nuclear chart. While remarkable agreement has been found between different many-body methods for a given nuclear Hamiltonian, the comparison with experiment and the understanding of theoretical uncertainties are still important open questions. The observed discrepancies to experiment indicate deficiencies in presently used nuclear interactions and operators. Chiral effective field theory (EFT) allows to systematically derive contributions to nucleon-nucleon (NN), three-nucleon (3N) and higher-body interactions including estimates of theoretical uncertainties. While the treatment of NN interactions in many-body calculations is well established, the calculation of 3N interactions and their incorporation in ab initio frameworks is still a frontier. This work reviews in detail recent and current developments on the derivation and implementation of improved 3N interactions and provides a comprehensive introduction to fundamental methods for their practical calculation and representation. We further give an overview of novel and established methods that facilitate the inclusion and treatment of 3N interactions in ab initio nuclear structure frameworks and present a selection of the latest calculations of atomic nuclei as well as nuclear matter based on state-of-the-art nuclear NN and 3N interactions derived within chiral EFT. Finally, we discuss ongoing efforts, open questions and future directions.

    nucl-thastro-ph.HEnucl-exPhys.Rept.(2021)·179 citations
  2. 02

    Accelerating longitudinal expansion of resistive relativistic-magneto-hydrodynamics in heavy ion collisions

    M. Haddadi Moghaddam🇮🇹 · W. M. Alberico🇮🇹 · Duan She🇨🇳 · A. F. Kord🇮🇷 · B. Azadegan🇮🇷

    We study the evolution of the longitudinal expansion of an ideal fluid with finite electrical conductivity, which is subject to the EM fields. In the framework of resistive relativistic-magneto-hydrodynamic, we find an exact analytical solution for the EM fields and for the acceleration of the fluid.

    nucl-thhep-thPRD(2020)·6 citations
  3. 03

    Ultrarelativistic quark-nucleus scattering in a light-front Hamiltonian approach

    Meijian Li🇺🇸 · Xingbo Zhao🇨🇳 · Pieter Maris🇺🇸 · Guangyao Chen🇺🇸 · Yang Li🇺🇸 · Kirill Tuchin🇺🇸 · James P. Vary🇺🇸

    We investigate the scattering of a quark on a heavy nucleus at high energies using the time-dependent basis light-front quantization (tBLFQ) formalism, which is the first application of the tBLFQ formalism in QCD. We present the real-time evolution of the quark wave function in a strong classical color field of the relativistic nucleus, described as the Color Glass Condensate. The quark and the nucleus color field are simulated in the QCD SU(3) color space. We calculate the total and the differential cross sections, and the quark distribution in coordinate and color spaces using the tBLFQ approach. We recover the eikonal cross sections in the eikonal limit. We find that the differential cross section from the tBLFQ simulation is in agreement with a perturbative calculation at large , and it deviates from the perturbative calculation at small due to higher-order contributions. In particular, we relax the eikonal limit by letting the quark carry realistic finite longitudinal momenta. We study the sub-eikonal effect on the quark through the transverse coordinate distribution of the quark with different longitudinal momentum, and we find the sub-eikonal effect to be sizable. Our results can significantly reduce the theoretical uncertainties in small region which has important implications to the phenomenology of the hadron-nucleus and deep inelastic scattering at high energies.

    nucl-thhep-phPRD(2020)·38 citations
  4. 04

    Nuclear multipole responses from chiral effective field theory interaction

    B. S. Hu · Q. Wu · Q. Yuan · Y. Z. Ma · X. Q. Yan · F. R. Xu

    We probe nuclear multipole resonances in the framework of the random-phase approximation by using the interaction obtained from the chiral effective field theory. The three-nucleon force is included in a form of the in-medium two-nucleon interaction which was derived from the chiral three-nucleon force. The isoscalar monopole, isoscalar dipole, isovector dipole and isoscalar quadrupole resonances of the closed-shell Ni have been investigated. The calculations reasonably reproduce the experimental multipole resonances of Ni, and well describe the pygmy dipole resonance and dipole polarizability measured in Ni. The multipole resonances of Ni, including pygmy dipole resonance and dipole polarizability, are predicted. The detailed effects of the tensor force and three-body force are analyzed by dissecting the chiral interaction. We find that in general the tensor force effect on electric giant resonances is not as significant as the effect from the three-body force, although the tensor force provides more than half of the binding energy. The effect from three-body force is strong in light nuclei. Particularly, three-body force is crucial for the formation of the pygmy resonance in calculations.

    nucl-thnucl-exPRC(2020)·8 citations
  5. 05

    Signatures of the vortical quark-gluon plasma in hadron yields

    ExHIC-P Collaboration · Hidetoshi Taya · Aaron Park · Sungtae Cho · Philipp Gubler · Koichi Hattori · Juhee Hong · Xu-Guang Huang · Su Houng Lee · Akihiko Monnai · Akira Ohnishi · Makoto Oka · Di-Lun Yang

    We investigate the hadron production from the vortical quark-gluon plasma created in heavy-ion collisions. Based on the quark-coalescence and statistical hadronization models, we show that total hadron yields summed over the spin components are enhanced by the local vorticity with quadratic dependence. The enhancement factor amounts to be a few percent and may be detectable within current experimental sensitivities. We also show that the effect is stronger for hadrons with larger spin, and thus propose a new signature of the local vorticity, which may be detected by the yield ratio of distinct hadron species having different spins such as and . The vorticity dependence of hadron yields seems robust, with consistent predictions in both of the hadron production mechanisms for reasonable values of the vorticity strength estimated for heavy-ion collisions.

    nucl-thhep-phnucl-exPRC(2020)·14 citations
  6. 06

    Trees and Forests in Nuclear Physics

    Marco Carnini · Alessandro Pastore

    We present a simple introduction to the decision tree algorithm using some examples from nuclear physics. We show how to improve the accuracy of the classical liquid drop nuclear mass model by performing Feature Engineering with a decision tree. Finally, we apply the method to the Duflo-Zuker model showing that, despite their simplicity, decision trees are capable of improving the description of nuclear masses using a limited number of free parameters.

    nucl-thcs.LGnucl-exJ.Phys.G(2020)·22 citations
  7. 07

    Reanalysis of N()O reaction and its role in stellar CNO cycle

    S. B. Dubovichenko · R. Ya. Kezerashvili · N. A. Burkova · A. V. Dzhazairov-Kakhramanov · B. Beisenov

    Within the framework of the modified potential cluster model with forbidden states, the N()O reaction rate and the astrophysical -factor are considered. It is shown that the first % N resonance determines the -factor and contributions of the and transitions are negligible at energies MeV, but are significant at high energies. The -factor strongly depends on the resonance parameters. The influence of the width of \ the resonance on % -factor is demonstrated. The reaction rate is calculated and an analytical approximation for the reaction rate is proposed. A comparison of our calculation with existing data is addressed. Results of our calculations for the N(O reaction rate provide the contribution to the steadily improving reaction rate database libraries. Our calculations of the N(O reaction rate along with results for the rates of N(O and CN processes provide the temperature range for the conversion of CNO cycle to the HCNO cycle. Our results demonstrate that at early stages of a nova explosion at temperatures about and at late stages of evolution of supermassive stars at temperatures about the ignition of the HCNO cycle could occur at much lower densities of a stellar medium.

    nucl-thPRC(2020)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE