Novel relativistic mean field Lagrangian guided by pseudo-spin symmetry restoration *

Abstract

The relativistic mean field (RMF) model has achieved great success in describing various nuclear phenomena. However, several serious defects are common. For instance, the pseudo-spin symmetry of high-l orbits is distinctly violated in general, leading to spurious shell closures and . This leads to problems in describing structure properties, including shell structures, nuclear masses, etc. Guided by the pseudo-spin symmetry restoration [Geng et al., Phys. Rev. C, 100: 051301 (2019)], a new RMF Lagrangian DD-LZ1 is developed by considering the density-dependent meson-nucleon coupling strengths. With the newly obtained RMF Lagrangian DD-LZ1, satisfactory descriptions can be obtained for the bulk properties of nuclear matter and finite nuclei. In particular, significant improvements on describing the single-particle spectra are achieved by DD-LZ1. In particular, the spurious shell closures and , commonly found in previous RMF calculations, are eliminated by the new effective interaction DD-LZ1, and consistently the pseudo-spin symmetry (PSS) around the Fermi levels is reasonably restored for both low-l and high-l orbits. Moreover, the description of nuclear masses is also notably improved by DD-LZ1, as compared to the other RMF Lagrangians.

The possibility of the secondary object in GW190814 as a neutron star

“…is removed in DD-LZ1 parametrization, which can give more precise shell evaluations of finite nuclei around Z = 58 and 92 (Wei et al 2020). For ρ meson, its coupling constant is also changed accordingly as…”

“…Ten years ago, it was showed by Sun et al (Sun et al 2008) that some parameterizations of DDRMF and DDRHF models generated massive neutron stars around 2.33 − 2.48 M ⊙ such as PKDD (Long et al 2004), DD-ME1 (Nikšić et al 2002), DD-ME2 (Lalazissis et al 2005), PKO1, PKO2, and PKO3 (Long et al 2006) sets, whereas properties of neutron star at 1.4 M ⊙ were not carefully discussed due to the deficiencies of astronomical observables. In 2020, several DDRMF parameters, DD-MEX (Taninah et al 2020), DD-LZ1 (Wei et al 2020), and DDV, DDVT, DDVTD (Typel & Terrero 2020) were proposed by different groups by fitting ground state properties of spherical finite nuclei, which considered the parametric correlations, shell evaluations, and tensor couplings of the vector mesons to nucleons, respectively. Therefore, it is necessary to systematically calculate the properties of neutron star with these latest DDRMF parameterizations and discuss the possibility of the secondary object of GW190817 as a neutron star.…”

New effective interactions for hypernuclei in density dependent relativistic mean field model

“…Therefore we are left with g σΛ and g ωΛ to be fixed. Many DD-RMF effective interactions have been proposed for normal nuclei, e.g., TW99 [49], DD-ME1 [50], PKDD [43], DD-ME2 [101], DD [102], D 3 C [102], PKO1 and PKO2 [103], PKO3 [104], PKA1 [105], DD2 [106], DDMEδ [107], DDME-X [108], DD-LZ1 [109] and DDV, DDS, DDVT, DDST, DDVTD and DDSTD [110]. Most of them can provide a good description for the properties not only of nuclear matter but also of finite nuclei around and far from the valley of β stability.…”

Heavy Magnetic Neutron Stars

“…For the present study, we employ two recently proposed density dependent DD-MEX (Taninah et al 2020), and DD-LZ1 (Wei et al 2020) parameter sets. These include the necessary tensor couplings of the vector mesons to nucleons and were obtained by fitting the ground state properties of finite nuclei, which considered parametric corrections and shell evaluations of mesons.…”