PaperPanorama
FAQ

Nuclear Theory·nucl-th

Thursday·January 6, 2022

8 papers—5 primary·3 cross-listed

All8Primary5Cross-lists3
  1. 01

    The S pairing gap in neutron matter

    S. Gandolfi · G. Palkanoglou · J. Carlson · A. Gezerlis · K. E. Schmidt

    We report ab initio calculations of the S wave pairing gap in neutron matter calculated using realistic nuclear Hamiltonians that include two- and three-body interactions. We use a trial state, properly optimized to capture the essential pairing correlations, from which we extract ground state properties by means of auxiliary field diffusion Monte Carlo simulations. We extrapolate our results to the thermodynamic limit by studying the finite-size effects in the symmetry-restored projected Bardeen-Cooper-Schrieffer (PBCS) theory and compare our results to other ab initio studies done in the past. Our quantum Monte Carlo results for the pairing gap show a modest suppression with respect to the mean-field BCS values. These results can be connected to cold atom experiments, via the unitarity regime where fermionic superfluidity assumes a unified description, and they are important in the prediction of thermal properties and the cooling of neutron stars.

    nucl-thcond-mat.quant-gasCondens.Mat.(2022)·31 citations
  2. 02

    Determination of neutron-skin thickness using configurational information entropy

    Chunwang Ma · Yipu Liu · Huiling Wei · Jie Pu · Kaixuan Cheng · Yuting Wang

    Configurational information entropy (CIE) theory was employed to determine the neutron skin thickness of neutron-rich calcium isotopes. The nuclear density distributions and fragment cross-sections in 350 MeV/u Ca + Be projectile fragmentation reactions were calculated using a modified statistical abrasion-ablation model. CIE quantities were determined from the nuclear density, isotopic, mass, and charge distributions. The linear correlations between the CIE determined using the isotopic, mass, and charge distributions and the neutron skin thickness of the projectile nucleus show that CIE provides new methods to extract the neutron skin thickness of neutron-rich nuclei.

    nucl-thNucl.Sci.Tech.(2022)·19 citations
  3. 03

    The resonance as a genuine three-quark or molecular state

    B. Golli🇸🇮 · H. Osmanović🇧🇦 · S. Širca🇸🇮

    The mechanism for the formation of the resonance is studied in a chiral quark model that includes quark-meson as well as contact (four point) interactions. The negative-parity -wave scattering amplitudes for strangeness and are calculated within a unified coupled-channel framework that includes the , , , , , , and channels and possible genuine three-quark bare singlet and octet states corresponding to resonances. We show that in order to reproduce the scattering amplitudes in the partial wave it is important to include the pertinent three-quark octet states as well as the singlet state, while the inclusion of the contact term is not mandatory. The Laurent-Pietarinen expansion is used to determine the -matrix poles. Following their evolution as a function of increasing interaction strength, the mass of the singlet state is strongly reduced due to the attractive self-energy in the and channels; when it drops below the threshold, the state acquires a dominant component which can be identified with a molecular state. The attraction between the kaon and the nucleon is generated through the interaction rather than by meson-nucleon forces.

    nucl-thhep-phEPJA(2022)·0 citations
  4. 04

    Nucleon momentum gap in asymmetric nuclear matter

    Gao-Chan Yong

    For more than half a century, nucleons are considered to move continuously in the nuclei. Recent electron-scattering experiments indicate about 2025\% nucleons in heavier nuclei are involved in the neutron-proton short-range correlations. Nucleons in the nuclei thus have abnormal behavior unlike those in the non-interaction fermi gas. In the neutron-rich nuclei, around the Fermi momentum, the neutron-proton short-range correlations lead to a momentum gap in the proton momentum distribution, which is circumstantially supported by the pionic experimental data. Likewise, there should also be a neutron momentum gap in the proton-rich nuclei. Nucleon momentum gap is thought to have profound and extensive implications in the studies ranging from particle physics to neutron stars as well as ultra-cold atomic gases.

    nucl-thnucl-exPRC(2022)·5 citations
  5. 05

    A Chiral Mean-Field Equation-of-State in UrQMD: Effects on the Heavy Ion Compression Stage

    Manjunath Omana Kuttan🇩🇪 · Anton Motornenko🇩🇪 · Jan Steinheimer🇩🇪 · Horst Stoecker🇩🇪 · Yasushi Nara🇯🇵 · Marcus Bleicher🇩🇪

    It is shown that the initial compression in central heavy ion collisions at beam energies of ~GeV depends dominantly on the underlying equation of state and only marginally on the model used for the dynamical description. To do so, a procedure to incorporate any equation of state in the UrQMD transport model is introduced. In particular we compare the baryon density, temperature and pressure evolution as well as produced entropy in a relativistic ideal hydrodynamics approach and the UrQMD transport model, where the same equation of state is used in both approaches. Not only is the compression similar if the same equation of state is used in either dynamical model, but it also strongly depends on the actual equation of state. These results indicate that the equation of state can be studied with observables which are sensitive to the initial compression phase and maximum compression achieved in heavy ion collisions at these beam energies.

    nucl-thhep-phEPJC(2022)·32 citations

Affiliations

first authorsco-authorsvia INSPIRE