Quark stars in massive gravity might be candidates for the mass gap objects

J. Sedaghat; B. Eslam Panah; R. Moradi; S. M. Zebarjad; G. H. Bordbar

doi:10.1140/epjc/s10052-024-12505-2

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2024) 84: 171
https://doi.org/10.1140/epjc/s10052-024-12505-2

Regular Article - Theoretical Physics

Quark stars in massive gravity might be candidates for the mass gap objects

J. Sedaghat¹, B. Eslam Panah²^b, R. Moradi³, S. M. Zebarjad¹ and G. H. Bordbar¹

¹ Department of Physics, Shiraz University, 71454, Shiraz, Iran
² Department of Theoretical Physics, Faculty of Science, University of Mazandaran, P.O. Box 47415-416, Babolsar, Iran
³ Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing, China

^b eslampanah@umz.ac.ir

Received: 8 November 2023
Accepted: 31 January 2024
Published online: 19 February 2024

Abstract

We have investigated the structural properties of strange quark stars (SQSs) in a modified theory of gravity known as massive gravity. In order to obtain the equation of state (EOS) of strange quark matter, we have employed a modified version of the Nambu–Jona-Lasinio model (MNJL) which includes a combination of NJL Lagrangian and its Fierz transformation by using weighting factors $(1 - α)$ $(1-\alpha )$ and $α .$ $\alpha .$ Additionally, we have also calculated dimensionless tidal deformability $(Λ)$ $(\Lambda )$ in massive gravity. To constrain the allowed values of the parameters appearing in massive gravity, we have imposed the condition $Λ_{1.4 M_{⊙}} ≲ 580 .$ $\Lambda _{1.4 {M}_{\odot }}\lesssim 580 .$ Notably, in the MNJL model, the value of $α$ $\alpha$ varies between zero and one. As $α$ $\alpha$ increases, the EOS becomes stiffer, and the value of $Λ$ $\Lambda$ increases accordingly. We have demonstrated that by softening the EOS with increasing the bag constant, one can obtain objects in massive gravity that not only satisfy the constraint $Λ_{1.4 M_{⊙}} ≲ 580,$ $\Lambda _{1.4 {M} _{\odot }}\lesssim 580,$ but they also fall within the unknown mass gap region $(2.5 M_{⊙} - 5 M_{⊙}) .$ $(2.5{M}_{\odot }-5{M}_{\odot }).$ To establish that the obtained objects in this region are not black holes, we have calculated Schwarzschild radius, compactness, and $Λ_{M_{TOV}}$ $\Lambda _{{M_{TOV}}}$ in massive gravity.

© The Author(s) 2024

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