In this work, we study the properties of neutron stars using the linear Relativistic Mean-Field (RMF) theory and consider multiple degrees of freedom inside neutron stars, including hyperons and $Δ$ resonances. We investigate different coupling parameters $x_{σΔ}$ between $Δ$ resonances and nucleons and compare the differences between neutron stars with and without strange mesons $σ^*$ and $ϕ$. These effects include particle number distributions, equations of state (EOS), mass-radius relations, and tidal deformabilities. To overcome the "hyperon puzzle," we employ the $σ-cut$ scheme to obtain neutron stars with masses up to $2M_{\odot}$. We find that strange mesons appear at around 3$ρ_0$ and reduce the critical density of baryons in the high-density region. With increasing coupling parameter $x_{σΔ}$, the $Δ$ resonances suppress hyperons, leading to a shift of the critical density towards lower values. The early appearance of $Δ$ resonances may play a crucial role in the stability of neutron stars. Strange mesons soften the EOS slightly, while $Δ$ resonances predominantly soften the EOS in the low-density region. By calculating tidal deformabilities and comparing with astronomical observation GW170817, we find that the inclusion of $Δ$ resonances decreases the radius of neutron stars.
The effects of $ϕ$-meson on properties of hyperon stars are studied systematically in the framework of the density dependent relativistic mean field (DDRMF) model. The $ϕ$-meson shifts hyperon threshold to a higher density and reduces the hyperon fractions in neutron star cores. It also strongly stiffens the equation of state (EoS) calculated with various DDRMF effective interactions and increases the maximum mass of hyperon stars, but only a few effective interactions survive under the constraints from recent astrophysical observations. In the DDRMF model, the conformal limit of sound velocit…
We develop a new equation of state (EoS) table involving thermal (anti)kaons, Bose-Einstein condensate of $K^{-}$ mesons and $Λ$-hyperons for core-collapse supernova and neutron star merger simulations. This EoS table is based on a finite temperature density-dependent relativistic hadron field theory where baryon-baryon interaction is mediated by scalar $σ$, vector $ω$ and $ρ$ mesons, using the parameter set DD2 for nucleons. The repulsive hyperon-hyperon interaction is mediated by an additional strange $ϕ$ meson. The EoS for the $K^-$ condensed matter is also calculated within the framework o…
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…
Possible coexistence of kaon condensation and hyperons in highly dense matter [the ($Y+K$) phase] is investigated on the basis of the relativistic mean-field theory combined with the effective chiral Lagrangian. Two coupling schemes for the $s$-wave kaon-baryon interaction are compared regarding the onset density of kaon condensation in the hyperon-mixed matter and equation of state for the developed ($Y+K$) phase: One is the contact interaction scheme related to the nonlinear effective chiral Lagrangian. The other is the meson-exchange scheme, where the interaction vertices between the kaon f…
In this work we revisit the quantum hadrodynamics (QHD) formalism to investigate hyperonic and hybrid stars with hyperon-meson couplings fixed via broken SU(6) group, in favor of a more general flavor group SU(3). We also employ an additional channel, the strangeness-hidden $ϕ$ meson, which couples only to the hyperons. In hybrid stars, the quark phase is built with the SU(3) NJL model also with an additional vector channel in the Lagrangian. We found that within the models chosen the hyperon puzzle cannot be avoided by the quark-hadron phase transition, once the hyperon threshold always happe…
We report a new equation of state (EoS) of cold and hot hyperonic matter constructed in the framework of the quark-meson-coupling (QMC-A) model. The QMC-A EoS yields results compatible with available nuclear physics constraints and astrophysical observations. It covers the range of temperatures from T=0 to 100 MeV, entropies per particle S/A between 0 and 6, lepton fractions from Y$_L$=0.0 to 0.6, and baryon number densities n$_B$=0.05-1.2 fm$^{-3}$. Applications of the QMC-A EoS are made to cold neutron stars (NS) and to hot proto-neutron stars (PNS) in two scenarios, (i) lepton rich matter w…
The in-medium behavior of bottom-strange pseudoscalar mesons in hot, isospin asymmetric and dense hadronic environment is studied using a chiral effective model. The same was recently generalized to the heavy quark sector and employed to study the behavior of open-charm and open-bottom mesons. The heavy quark (anti-quark) is treated as frozen and all medium modifications of these bottom-strange mesons are due to their strange anti-quark (quark) content. We observe a pronounced dependence of their medium mass on baryonic density and strangeness content of the medium. Certain aspects of these in…
Hyperons are essential constituents in the neutron star interior. The poorly-known hyperonic interaction is a source of uncertainty for studying laboratory hypernuclei and neutron star observations. In this work, we perform Bayesian inference of phenomenological hyperon-nucleon interactions using the tidal-deformability measurement of the GW170817 binary neutron star merger as detected by LIGO/Virgo and the mass-radius measurements of PSR J0030+0541 and PSR J0740+6620 as detected by NICER. The analysis is based on a set of stiff relativistic neutron-star-matter equation of states with hyperons…
Hyperon longitudinal polarization and vector meson spin alignment in a thermal model for heavy-ion collisions
National Institute of Science Education and Research（国家科学教育研究中心）；Indian Institute of Science Education and Research Berhampur（印度科学教育与研究学院贝尔汉普尔分校）；Jagiellonian University（雅盖隆大学）；Polish Academy of Sciences（波兰科学院）
The recent measurement of the mass of neutron stars (PSR J1614 - 2230, PSR J0348 + 0432, MSP J0740 + 6620) restricts the lower limit $\sim 2M_{\odot}$ of the maximum mass of such compact stars, making it possible for dense matter to exist in massive stars. The relativistic mean field theory with parameter sets FSUGold including Kaon condensation is used to describe the properties of neutron stars in $β$ equilibrium. Through careful choice of the parameter of the $σ$-cut $c_σ$, we are able to produce a maximum mass neutron star with Kaon condensation heavier than $2M_{\odot}$, and we find that …
A systematic study of global spin polarizations and correlations of hadrons with different spins in relativistic heavy ion collisions
Institute of Frontier and Interdisciplinary Science, Key Laboratory of Particle Physics and Particle Irradiation (MOE), Shandong University（山东大学前沿交叉科学研究中心，粒子物理与粒子辐照教育部重点实验室）
