Density-dependent relativistic mean field approach and its application to single-Λhypernuclei in oxygen hyperisotopes  

作　　者：丁士缘 杨威 孙保元 Shi-Yuan Ding;Wei Yang;Bao-Yuan Sun(MOE Frontiers Science Center for Rare Isotopes,Lanzhou University,Lanzhou 730000,China;School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China)

机构地区：[1]MOE Frontiers Science Center for Rare Isotopes,Lanzhou University,Lanzhou 730000,China [2]School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China

出　　处：《Chinese Physics C》2023年第12期102-114,共13页中国物理C（英文版）

基　　金：the Fundamental Research Funds for the Central Universities,Lanzhou University(lzujbky-2022-sp02,lzujbky-2023-stlt01);the National Natural Science Foundation of China(11875152,12275111);the Strategic Priority Research Program of Chinese Academy of Sciences(XDB34000000)。

摘　　要：The in-medium feature of nuclear force, which includes both nucleon-nucleon( NN) and hyperon-nucleon( ΛN) interactions, impacts the description of single-Λ hypernuclei. With the alternated mass number or isospin of hypernuclei, such effects may be unveiled by analyzing the systematic evolution of the bulk and single-particle properties. From a density-dependent meson-nucleon/hyperon coupling perspective, a new ΛN effective interaction in the covariant density functional(CDF) theory, namely, DD-LZ1-Λ1, is obtained by fitting the experimental data ofΛ separation energies for several single-Λ hypernuclei. It is then used to study the structure and transition properties of single-Λ hypernuclei in oxygen hyperisotopes, in comparison with those determined using several selected CDF Lagrangians. A discrepancy is explicitly observed in the isospin evolution of Λ1p spin-orbit splitting with various effective interactions, which is attributed to the divergence of the meson-hyperon coupling strengths with increasing density. In particular, the density-dependent CDFs introduce an extra contribution to reduce the value but enhance the isospin dependence of the splitting, which originates from the rearrangement terms of Λ self-energies. In addition, the characteristics of hypernuclear radii are studied along the isotopic chain. Owing to the impurity effect of theΛ hyperon, a size shrinkage is observed in the matter radii of hypernuclei compared with the cores of normal nuclei,and its magnitude is further elucidated to correlate with the incompressibility of nuclear matter. Moreover, there is a sizable model-dependent trend in which the Λ hyperon radii evolve with neutron number, which is decided partly by the in-medium NN interactions and core polarization effects.

关 键 词：relativistic mean field theory HYPERNUCLEI oxygen isotopes covariant density functional theory 

分 类 号：O412.1[理学—理论物理]