Influence of scalar-isovector delta-meson field on quark phase structure in neutron stars

Scalar-Isovector Delta-Meson in the Relativistic Mean-Field Theory and the Structure of Neutron Stars with a Quark Core

In the framework of the relativistic mean-field theory, we have considered the equation of state of superdense nuclear matter, taking into account an effective scalar-isovector delta-meson field. The effect of the delta-meson field on the characteristics of a Maxwell-type quark phase transition has been studied. The quark phase is described with the aid of the improved version of the MIT (Massachusetts Institute of Technology) bag model, in which interactions between the u, d, s quarks inside the bag are taken into account in the one-gluon exchange approximation. For different values of the ba…

Relativistic mean field interaction with density dependent meson-nucleon vertices based on microscopical calculations

Although ab-initio calculations of relativistic Brueckner theory lead to large scalar isovector fields in nuclear matter, at present, successful versions of covariant density functional theory neglect the interactions in this channel. A new high precision density functional DD-ME$δ$ is presented which includes four mesons $σ$, $ω$, $δ$, and $ρ$ with density dependent meson-nucleon couplings. It is based to a large extent on microscopic ab-initio calculations in nuclear matter. Only four of its parameters are determined by adjusting to binding energies and charge radii of finite nuclei. The oth…

Many-body forces in the equation of state of hyperonic matter

In this work we introduce an extended version of the formalism proposed originally by Taurines et al. that considers the effects of many-body forces simulated by non-linear self-couplings and meson-meson interaction contributions. In this extended version of the model, we assume that matter is at zero temperature, charge neutral and in beta-equilibrium, considering that the baryon octet interacts by the exchange of scalar-isoscalar ($σ$,$\,σ^*$), vector-isoscalar ($ω$,$\,ϕ$), vector-isovector ($\varrho$) and scalar-isovector ($δ$) meson fields. Using nuclear matter properties, we constrain the…

在包含同位旋标量介子的扩展宇称双重态模型中，来自HESS J1731-347的手征不变质量约束

Chiral Invariant Mass Constraints from HESS J1731 347 in an Extended Parity Doublet Model with Isovector Scalar Meson

利用含同位旋标量介子的扩展宇称双重态模型，从HESS J1731-347观测数据约束核子手征不变质量，发现$m_0$在740-860 MeV时满足所有2σ约束，但1σ约束与对称性不可压缩系数不完全兼容。

Deconfinement Phase Transition in Neutron Stars and δ-Meson Field

The Maxwell and Glendenning construction scenarios of deconfinement phase transition in neutron star matter are investigated. The hadronic phase is described within the relativistic mean-field (RMF) theory, if also the scalar-isovector δ-meson field is taken into account. The strange quark phase is described in the frame of MIT bag model, including the effect of perturbative one-gluon exchange interactions. The influence of the δ-meson field on the deconfinement phase transition boundary characteristics is discussed.