arXiv subjects

Tuhin Malik

Publications and source records attributed to Tuhin Malik.

59 records · Page 4Linked to original sources

arXiv2019

Confronting nuclear equation of state in the presence of dark matter using GW170817 observation in relativistic mean field theory approach

We confront admixture of dark matter inside neutron star using gravitational wave constraints coming from binary neutron star merger. We consider a relativistic mean field model including $σ-ω-ρ$ meson interaction with NL3 parameterization. We study fermionic dark matter interacting with nucleonic matter via Higgs portal mechanism. We show that admixture of dark matter inside the neutron star soften the equation state and lower the value of tidal deformability. Gravitational wave GW170817 observation puts an upper bound on tidal deformability of a binary neutron star with low spin prior at 90\% confidence level, which disfavors stiff equation of state such as Walecka model with NL3 parameterization. However, we show that Walecka model with NL3 parameterization with a fermionic dark matter component satisfy the tidal deformability bound coming from the GW170817 observation.

hep-ph↗

arXiv2018

The nucleon effective mass and its isovector splitting

Using an energy density functional (EDF) based on the thermodynamic Gibbs-Duhem relation, found equivalent to the standard Skyrme EDF for infinite nuclear matter, it is demonstrated that the parameters of this EDF are not uniquely determined from the fit of the empirical and theoretical data related to nuclear matter. This prevents an unambiguous determination of the nucleon effective mass ($\frac{m_0^*}{m}$) and its isovector splitting ($Δm_0^*$). Complementary information from dipole polarizability of atomic nuclei helps in removing this ambiguity and plausible values of $\frac{m_0^*}{m}$ and $Δm_0^*$ can be arrived at. Presently considered fit data on infinite nuclear matter and dipole polarizability of finite nuclei yield $\frac{m_0^*}{m} =0.68 \pm 0.04 $ and $Δm_0^* =(-0.20 \pm 0.09)δ$. This EDF is consistent with the constraint on the maximum mass of the neutron star.

nucl-th↗

arXiv2018

Impact of Magnetic field on neutron star properties

We derive an equation of state for magnetized charge neutral nuclear matter relevant for neutron star structure. The calculations are performed within an effective chiral model based on generalization of sigma model with nonlinear self interactions of the sigma mesons along with vector mesons and a $ρ-σ$ cross-coupling term. The effective chiral model is extended by introducing the contributions of strong magnetic field on the charged particles of the model. The contributions arising from the effects of magnetic field on the Dirac sea of charged baryons are also included. The resulting equation of state for the magnetized dense matter is used to investigate the neutron star properties, like, mass-radius relation and tidal deformability. The dimensionless tidal deformability of $1.4~{M}_\odot$ NS is found to be $Λ_{1.4}=526$, which is consistent with recent observation of GW170817. The maximum mass of neutron star in presence of strong magnetic field is consistent with the observational constraints on mass of neutron star from PSR~ J0348 - 0432 and the radius at $1.4~{M}_\odot$ mass of the neutron star is within the empirical bounds.

nucl-th↗

arXiv2018

GW170817: constraining the nuclear matter equation of state from the neutron star tidal deformability

Constraints set on key parameters of the nuclear matter equation of state (EoS) by the values of the tidal deformability, inferred from GW170817, are examined by using a diverse set of relativistic and non-relativistic mean field models. These models are consistent with bulk properties of finite nuclei as well as with the observed lower bound on the maximum mass of neutron star $\sim 2 ~ {\rm M}_\odot$. The tidal deformability shows a strong correlation with specific linear combinations of the isoscalar and isovector nuclear matter parameters associated with the EoS. Such correlations suggest that a precise value of the tidal deformability can put tight bounds on several EoS parameters, in particular, on the slope of the incompressibility and the curvature of the symmetry energy. The tidal deformability obtained from the GW170817 and its UV/optical/infrared counterpart sets the radius of a canonical $1.4~ {\rm M}_{\odot}$ neutron star to be $11.82\leqslant R_{1.4}\leqslant13.72$ km.

nucl-th↗

arXiv2017

Nuclear symmetry energy with mesonic cross-couplings in the effective chiral model

The effective chiral model is extended by introducing the contributions from the cross-couplings between isovector and isoscalar mesons. These cross-couplings are found to be instrumental in improving the density content of the nuclear symmetry energy. The nuclear symmetry energy as well as its slope and curvature parameters at the saturation density are in harmony with those deduced from a diverse set of experimental data. The equation of state for pure neutron matter at sub-saturation densities is also in accordance with the ones obtained from different microscopic models. The maximum mass of neutron star is consistent with the measurement and the radius at the canonical mass of the neutron star is within the empirical bounds.

nucl-th↗