Investigating Dark Matter-Admixed Neutron Stars with NITR Equation of State in Light of PSR J0952-0607

Abstract: The heaviest pulsar, PSR J0952-0607, with a mass of $M=2.35\pm0.17 \ M_\odot$, has recently been discovered in the disk of the Milky Way Galaxy. In response to this discovery, a new RMF model, "NITR" has been developed. The NITR model's naturalness has been confirmed by assessing its validity for various finite nuclei and nuclear matter (NM) properties, including incompressibility, symmetry energy, and slope parameter values of 225.11, 31.69, and 43.86 MeV, respectively. These values satisfy the empirical/experimental limits currently available. The maximum mass and canonical radius of a neutron star (NS) calculated using the NITR model parameters are 2.35 $M_\odot$ and 12.73 km, respectively, which fall within the range of PSR J0952-0607 and the latest NICER limit. This study aims to test the NITR model consistency by applying it to different systems and, consequently, calibrate its validity extensively. Subsequently, the NITR model equation of state (EOS) is employed to obtain the properties of a dark matter admixed neutron star using two approaches: non-gravitational (single fluid) and two-fluid. In the two-fluid model, the dark matter (DM) particles only interact with each other via gravity rather than the nucleons. In both cases, the equation of state becomes softer due to DM interactions, which reduces various macroscopic properties such as maximum mass, radius, tidal deformability, etc. Additionally, through the use of various observational data, efforts are made to constraint the quantity of DM within the NS.