Is it possible to separate baryonic from dark matter within the $\Lambda$-CDM formalism?

TL;DR

This paper explores whether baryonic and dark matter can be distinguished within the $\\Lambda$-CDM framework by extending scalar-tensor cosmological models with non-minimal coupling, demonstrating that such separation is theoretically feasible and consistent with observations.

Contribution

The authors develop solutions for matter conservation in extended scalar-tensor models and show that baryonic and dark matter can be separated via a chameleon effect within the $\\Lambda$-CDM paradigm.

Findings

Reproduces $\\Lambda$-CDM with high observational accuracy

Demonstrates compatibility with PPN parameter constraints

Shows matter bounce scenario replaces Big-Bang in phantom models

Abstract

We found general solutions of matter stress-energy (non-)conservation in scalar-tensor FLRW-type cosmological models by extending the logotropic formalism to the case of non-minimal coupling between the scalar field and new dark fluid candidates. The energy conditions expressed by the generating function are introduced. Next, we investigate the possibility of separating baryonic from dark matter and explain their ratio as a chameleon effect in the presence of non-minimal coupling. To answer the question affirmatively we analyze simple extensions of the $\Lambda$-CDM model by adding a non-minimally coupled scalar field in the Einstein frame. Two scenarios involving either a scalaron (quintessence) or a phantom (ghost) are numerically solved and compared. As a result, it is shown that in both cases LCDM model can be reproduced with a high accuracy in the region covered by observations. We have also demonstrated the compatibility of the two models under consideration with available PPN parameters estimations. As expected, in the case of the phantom (ghost) field the Big-Bang scenario is replaced by the (matter) Bounce.