Tidal deformability of neutron stars with exotic particles within a density dependent relativistic mean field model in R-squared gravity

TL;DR

This study investigates how exotic particles in neutron stars affect their properties within a non-perturbative $f(R)$ gravity framework, constraining model parameters using mass, radius, and tidal deformability data.

Contribution

It provides a non-perturbative analysis of neutron star properties with exotic particles in $f(R)$ gravity, highlighting constraints on the gravity model parameter from tidal deformability.

Findings

Mass-radius relations are broad for different $a$ values.

Tidal deformability constrains the parameter $a$ significantly.

Exotic particles influence neutron star structure and observable properties.

Abstract

There is a growing interest in investigating modified theories of gravity, primarily, with the aim of explaining the universe's accelerated expansion, which has been confirmed by several independent observations. Compact objects, like neutron stars, exhibit strong gravity effects and therefore are used to study modified gravity theories. We use the $f(R)=R+aR^2$ model, where R is the Ricci scalar and $a$ is a free parameter. This model has been studied both perturbatively and non-perturbatively. However, it was found that perturbative methods results in nonphysical solutions for the neutron stars. In this paper, we examine neutron star properties, such as mass, radius, tidal deformability in non-perturbative $f(R)$ gravity model with density dependant relativistic equation of state with different particle compositions. The strange particles in the core of NS in the form of ${\bf \Lambda}$ hyperons, $K^-$ condensate, and quarks are considered. We have observed that while the mass-radius relation allows for a wide range of parameter $a$, when tidal deformability is considered, the parameter $a$ is constrained down by one order.