Confusing dark matter particle properties with modifications to General Relativity

TL;DR

This paper compares Cold Dark Stars made of fermions in General Relativity and R-square gravity, revealing that different parameters can produce similar gravitational effects, potentially confusing dark matter properties with gravity modifications.

Contribution

It demonstrates that similar gravitational potentials can result from different model parameters in both theories, highlighting potential misinterpretations in dark matter and gravity research.

Findings

Same gravitational potential for different parameters

Potential confusion between dark matter properties and gravity modifications

Implications for interpreting astrophysical observations

Abstract

Cold Dark Stars made of self-gravitating fermions in the degenerate limit are constructed in General Relativity and in R-square gravity, $f(R)=R+\alpha R^2$. The properties of the resulting Cold Dark Stars in both theories of gravity are studied. It is found that the same gravitational potential is generated for different election of the parameters of the model, such as the mass of the fermion, the self-interacting strength or the value of $\alpha$, thus, a possible confusion in the determination of the dark matter properties and the favored theory of gravity might arise.