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Nuclear Theory·nucl-th

Thursday·September 24, 2020

12 papers—6 primary·6 cross-listed

All12Primary6Cross-lists6
  1. 01

    Relation between transition density and proton inelastic scattering by C target at 65 and 200 MeV

    T. Furumoto🇯🇵 · M. Takashina🇯🇵

    We calculate proton elastic and inelastic scatterings with a microscopic coupled channel (MCC) calculation. The localized diagonal and coupling potentials including the spin-orbit part are obtained by folding a complex -matrix effective nucleon-nucleon interaction with a transition density. This is the first time that the present folding prescription for the spin-orbit part is applied to the proton inelastic scattering, while for the monopole transition only. We apply the MCC calculation to the proton elastic and inelastic (0) scatterings by C target at = 65 and 200 MeV. The role of diagonal and coupling potentials for the central and spin-orbit parts is checked. In addition, the relation between the transition density and the proton inelastic scattering is investigated with the modified wave function and the modified transition density. Namely, we perform the investigation with the artificial drastic change rather than fine structural change. The inelastic cross section is sensitive to the strength and shape of the transition density, but the inelastic analyzing power is sensitive only to the shape of that. Finally, we make clear the property of the inelastic analyzing power derived from the transition density without an ambiguity.

    nucl-thnucl-exPRC(2021)·4 citations
  2. 02

    Phenomenological quark-hadron equations of state with first-order phase transitions for astrophysical applications

    Niels-Uwe F. Bastian🇵🇱

    In the current work an equation of state model with a first-order phase transition for astrophysical applications is presented. The model is based on a two-phase approach for quark-hadron phase transitions, which leads by construction to a first-order phase transition. The resulting model has already been successfully used in several astrophysical applications, such as cold neutron stars, core-collapse supernova explosions and binary neutron star mergers. Main goal of this work is to present the details of the model, discuss certain features and eventually publish it in a tabulated form for further use.

    nucl-thastro-ph.HEastro-ph.SRPRD(2021)·50 citations
  3. 03

    Variational and parquet-diagram calculations for neutron matter. II. Twisted Chain Diagrams

    E. Krotscheck · J. Wang

    We develop a manifestly microscopic method to deal with strongly interacting nuclear systems that have different interactions in spin-singlet and spin-triplet states. In a first step we analyze variational wave functions that have been suggested to describe such systems, and demonstrate that the so-called commutator contributions can have important effects whenever the interactions in the spin-singlet and the spin-triplet states are very different. We then identify these contributions as terms that correspond, in the language of perturbation theory, to non-parquet diagrams. We include these diagrams in a way that is suggested by the Jastrow-Feenberg approach and show that the corrections from non-parquet contributions are, at short distances, larger than all other many-body effects.

    nucl-thPRC(2020)·8 citations
  4. 04

    On the Speed of Sound in Hyperonic Stars

    T. F. Motta🇦🇺 · P. A. M. Guichon🇫🇷 · A. W. Thomas🇦🇺

    We build upon the remarkable, model independent constraints on the equation of state of dense baryonic matter established recently by Annala et al. [1]. Using the quark-meson coupling model, an approach to nuclear structure based upon the self-consistent adjustment of hadron structure to the local meson fields, we show that, once hyperons are allowed to appear in dense matter in \b{eta}-equilibrium, the equation of state is consistent with those constraints. As a result, while one cannot rule out the occurence of quark matter in the cores of massive neutron stars, the available constraints are also compatible with the presence of hyperons.

    nucl-thastro-ph.HENPA(2021)·30 citations
  5. 05

    Density-Dependent Neutron-Neutron Interaction from Subleading Chiral Three-Neutron Forces

    Lukas Treuer🇩🇪

    Three-nucleon forces are an essential ingredient for an accurate description of nuclear few- and many-body systems. However, implementing them directly in many-body calculations is technically very challenging. Thus, there is a need for an efficient approximation method. By closing one nucleon line to a loop, it is possible to derive effective in-medium nucleon-nucleon interactions that represent the underlying three-nucleon forces, as constructed in Chiral Effective Field Theory. Since three-neutron forces are equally as important for the computation of the equation of state for pure neutron matter, this work applies the aforementioned approach to the subleading chiral three-neutron forces, in particular the short-range terms and relativistic corrections. It is shown in this work that, while many contributions to the in-medium neutron-neutron interaction are - apart from a constant factor - identical to the terms in isospin-symmetric matter, some differ drastically. Moreover, previously vanishing terms yield now non-zero contributions. As a result of this work, density-dependent in-medium neutron-neutron potentials are now available for the implementation in nuclear many-body calculations, either in closed analytical form, or requiring at most one numerical integration.

    nucl-th6 citations
  6. 06

    The Spin Orbit term in the Nuclear Shell Model

    H. Müther

    Quasi-nuclear systems, representing nuclei with variable size, are studied to investigate the occurrence of the spin-orbit term in the nuclear mean field in the transition from infinite nuclear matter to finite nuclei. Relativistic as well as non-relativistic mean field calculations based on models for the nucleon-nucleon () interaction, which fit the scattering data, are considered. A very strong correlation between the strength of the spin-orbit term and radius of the nuclear system is observed. The origin of the spin-orbit term is analyzed by inspecting the contributions of the different partial waves and various mesons in a One-Boson-Exchange model of the interaction. The influence of correlation effects and the enhancement of the small component of Dirac spinors for nucleons in the nuclear medium is discussed.

    nucl-thPRC(2021)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE