Neutron stars in the braneworld within the Eddington-inspired Born-Infeld gravity

TL;DR

This paper explores how modified gravity and braneworld scenarios can resolve the hyperon puzzle in neutron stars, allowing for higher mass and radius consistent with observations by adjusting model parameters.

Contribution

It introduces a novel approach combining EiBI gravity and braneworld theory to model neutron stars, addressing the hyperon puzzle and matching observational data.

Findings

Neutron stars can reach ~2.1 solar masses with 10 km radius.

Varying EiBI coupling constant restores observational compatibility.

Finite brane tension reduces star compactness, affecting mass-radius relation.

Abstract

We propose the disappearance of "the hyperon puzzle" in neutron star (NS) by invoking two new-physics prescriptions: modified gravity theory and braneworld scenario. By assuming that NS lives on a $3$-brane within a $5d$ empty AdS bulk, gravitationally governed by Eddington-inspired Born-Infeld (EiBI) theory, the field equations can be effectively cast into the usual Einstein's with "apparent" anisotropic energy-momentum tensor. Solving the corresponding brane-TOV equations numerically, we study its mass-radius relation. It is known that the appearance of finite brane tension $\lambda$ reduces the compactness of the star. The compatibility of the braneworld results with observational constraints of NS mass and radius can be restored in our model by varying the EiBI's coupling constant, $\kappa$. We found that within the astrophysically-accepted range of parameters ($0<\kappa<6\times10^6\text{m}^2$ and $\lambda\gg1~ \text{MeV}^4$) the NS can have mass $\sim2.1~ \text{M}_\odot$ and radius $\sim10$ km.