8 research outputs found
Neutron star structure with nuclear force mediated by hypothetical X17 boson
A reported MeV boson, which has been proposed as an explanation to the
Be and He anomaly, is investigated in the context of its possible
influence to neutron stars structure. Implementing a =17 MeV to the
nuclear equation of state using different incompressibility values K=245
MeV and K=260 MeV and solving Tolman-Oppenheimer-Volkoff equations, we
estimate an upper limit of for a non rotating
neutron star with span in radius between km to km. Moving
away from pure - NN with admixture of 10\% protons and simulating possible
softening of equation of state due to hyperons, we see that our estimated
limits fit quite well inside the newest reported studies, coming from neutron
stars merger event, GW190814Comment: 5 pages, 4 figures, To appear in the EPJ Web of Conference
Constraints for the X17 boson from compacts objects observations
We investigate the hypothetical X17 boson on neutron stars and Quark Stars
(QSs) using various hadronic Equation of States (EoSs) with phenomenological or
microscopic origin. Our aim is to set realistic constraints on its coupling
constant and the mass scaling, with respect to causality and various possible
upper mass limits and the dimensionless tidal deformability . In
particular, we pay special attention on two main phenomenological parameters of
the X17, the one is related to the coupling constant that it has
with hadrons or quarks and the other with the in-medium effects through the
regulator . Both are very crucial concerning the contribution on
the total energy density and pressure. In the case of considering the X17 as a
carrier of nuclear force in Relativistic Mean Field (RMF) theory, an admixture
into vector boson segment was constrained by 20\% and 30\%. In our
investigation, we came to the general conclusion that the effect of the
hypothetical X17 both on neutron and QSs constrained mainly by the causality
limit, which is a specific property of each EoS. Moreover, it depends on the
interplay between the main two parameters that is the interaction coupling
and the in-medium effects regulator . These effects
are more pronounced in the case of QSs concerning all the bulk properties.Comment: 12 pages, 14 figures, 2 table
Relativistic density functional for nuclear matter
In the present work, we have mapped the exchange Fock contributions from the DiracāHartreeāFock (DHF) approach for nuclear matter onto the direct Hartree terms. This results in the relativistic mean field (RMF) model with the density dependent couplings. The density dependence of the effective coupling constants thus reflects the exchange correlations. The exchange part of an energy density of the linear DHF model in dense matter is evaluated in a parameter-free closed form and, after the rearrangement of the terms, expressed as density functional
Relativistic density functional for nuclear matter
In the present work, we have mapped the exchange Fock contributions from the DiracāHartreeāFock (DHF) approach for nuclear matter onto the direct Hartree terms. This results in the relativistic mean field (RMF) model with the density dependent couplings. The density dependence of the effective coupling constants thus reflects the exchange correlations. The exchange part of an energy density of the linear DHF model in dense matter is evaluated in a parameter-free closed form and, after the rearrangement of the terms, expressed as density functional
Universal Nuclear Equation of State Introducing the Hypothetical X17 Boson
Within the scope of the Symmetry journal special issue on: āThe Nuclear Physics of Neutron Starsā, we complemented the nuclear equation of state (EoS) with a hypothetical 17 MeV boson and observed that only instances with an admixture of 30%ā40% satisfy all of the constraints. The successful EoS resulted in a radius of around 13 km for a neutron star with mass MNSā1.4Mā and in a maximum mass of around MNSā2.5Mā. The value of the radius is in agreement with the recent measurement by NICER. The maximum mass is also in agreement with the mass of the remnant of the gravitational wave event GW190814. Thus, it appears that these EoSs satisfy all of the existing experimental constraints and can be considered as universal nuclear equations of state
Novel Concepts of Nuclear Physics in a Neutron Star Environment
Neutron stars are like nuclear physics laboratories, providing a unique opportunity to apply and search for new physics. In that spirit, we explored novel concepts of nuclear physics studied in a neutron star environment. Firstly, we investigated the reported 17 MeV boson, which has been proposed as an explanation to the 8Be, 4He and 12C anomaly, in the context of its possible influence on the neutron star structure, defining a universal Equation of State. Next, we investigated the synthesis of hyper-heavy elements under conditions simulating the neutron star environment