Feeble DM-SM Interaction via New Scalar and Vector Mediators in Rotating
  Neutron Stars
  We investigate the possible presence of dark matter (DM) in massive and
rotating neutron stars (NSs). For the purpose we extend our previous work [1]
to introduce a light new physics vector mediator besides a scalar one in order
to ensure feeble interaction between fermionic DM and $\beta$ stable hadronic
matter in NSs. The masses of DM fermion, the mediators and the couplings are
chosen consistent with the self-interaction constraint from Bullet cluster and
from present day relic abundance. Assuming that both the scalar and vector
mediators contribute equally to the relic abundance, we compute the equation of
state (EoS) of the DM admixed NSs to find that the present consideration of the
vector new physics mediator do not bring any significant change to the EoS and
static NS properties of DM admixed NSs compared to the case where only the
scalar mediator was considered [1]. However, the obtained structural properties
in static conditions are in good agreement with the various constraints on them
from massive pulsars like PSR J0348+0432 and PSR J0740+6620, the gravitational
wave (GW170817) data and the recently obtained results of NICER experiments for
PSR J0030+0451 and PSR J0740+6620. We also extended our work to compute the
rotational properties of DM admixed NSs rotating at different angular
velocities. The present results in this regard suggest that the secondary
component of GW190814 may be a rapidly rotating massive DM admixed NS. The
constraints on rotational frequency from pulsars like PSR B1937+21 and PSR
J1748-2446ad are also satisfied by our present results. Also, the constraints
on moment of inertia are satisfied considering slow rotation. The universality
relation in terms of normalized moment of inertia also holds good with our DM
admixed EoS.
