Role of Δs in determining the properties of neutron stars in parameterized hydrostatic equilibrium

Abstract

The possible existence of [Formula: see text] resonances is inspected in the cold dense matter of neutron star (NS) core in the presence of hyperons. The diverse effects of variation in [Formula: see text] mass on their formation and the equation of state (EoS) are studied in this work with an effective chiral model and the resultant NS properties are calculated with the help of parameterized Tolman–Oppenheimer–Volkoff (PTOV) equations to bring out the two important features of pressure in the context of massive NSs. The [Formula: see text] puzzle is re-explored and resolved taking into account the concept of modified/parametrized inertial pressure and self-gravity in case of massive pulsars like PSR J1614−2230 and PSR J0348-0432. It is seen that although the presence of exotic matter like the hyperons and [Formula: see text] softens the EoS considerably, their presence in massive NSs can be successfully explained with the theory of parametrized hydrostatic equilibrium conditions. The results of this work also satisfy the constraints on [Formula: see text] and [Formula: see text] from the gravitational wave (GW170817) detection of binary NS merger. The constraint on baryonic mass from PSR J0737-3039 is also satisfied with the solutions of the PTOV equations for all the [Formula: see text] masses considered.

Estimation of transport coefficients of dense hadronic and quark matter

“…Although it can be seen from [34] that few other parameter sets of the present model yield values of K which are consistent with [63,64], they cannot be adopted as they yield even softer EoS [34] and consequently do not satisfy the maximum mass constraint [1] of NSs. The present set satisfies this constraint [28,11,29,31,30,12]. The other SNM properties like the binding energy per nucleon B/A, the symmetry energy J and the saturation density ρ 0 match well with the estimates of Refs.…”

“…Similar mapping in the low/vanishing temperature and high baryon density domain might be possible [15] by fusing ultra-high density (approximately 10 times larger than the nuclear saturation density) pQCD calculations [24,25,26] and low density hadronic model calculations. In this context, present work attempts for comparing the estimations of transport coefficients, obtained from standard MIT Bag model for quark phase [27], and chiral hadronic model [11,28,29,30,12,31,32,33,34], relativistic mean field (RMF) model [35,36,37,38] for hadronic phase. Both the types of hadronic models have been explored thoroughly to construct the EoS of dense NSM and successfully determine the structural properties of NSs in the light of recent constraints from various astrophysical observations [11,28,29,30,12,37,38].…”

Nuclear matter at finite temperature and static properties of proto-neutron star

“…In comparison with other RMF models like NL3 etc, the model presents soft EoS which softens more with the inclusion of hyperons and ∆ baryons at high density [75,76,77,78]. Unlike various models [91,92,93,94,95] which produce stiff EoS and satisfy the 2 M criteria of NSs mass [70,71] even in the presence of hyperons and ∆s, the present model do not [75,76,77,78] when such heavier baryons are included. Moreover, the appearance of these heavier baryons are much uncertain as they are largely controlled by the different couplings.…”

A study of the elastic $πN$ scattering at finite baryon density

“…Those modifications are extremely crucial to study the neutron star (NS) and relativistic heavy-ion collision (RHIC) experiments with finite baryon density ρ B for instance. Among the various hadrons in medium, the appearance of the ∆(1232, 3/2 + ) resonance becomes crucial inside NS, since the energies in the core of NS is far more sufficient to create the resonance, which is heavier than neutron mass [4][5][6][7][8][9][10][11]. The stability of ∆-rich matter was also taken into account, using the covariant density functional theory [4].…”

“…The effects of the ∆ resonance to the NS properties, such as the mass-radii relations were investigated in Refs. [6,8,10], where the various QCD properties were also taken into account [7,9]. The external magnetic field induced to NS with the ∆ resonance were investigated in Ref.…”