Chameleonic dark matter and reheating constraints in a logarithmic f (R) gravity

We investigated the viability of a logarithmic f(R) gravity in calculating the reheating temperature and describing dark matter. We discovered that the logarithmic model possessed a chameleon problem, and we addressed this by modifying the model to incorporate the R2 term from the Starobinsky model. We examined the viability of the corrected model and revealed that it provided the same reheating temperature as the original logarithmic model, approximately 106.5GeV. However, the constraints on the parameter α are significantly different in the R2-Logarithmic f(R) gravity, in which we obtained α ≈√3 instead of 500 < α < 4000 in the original model. Furthermore, the R2-Logarithmic f(R) model avoids the chameleon problem, and the scalaron derived from the model can be a potential dark matter candidate with y (0,α-2). © 2023 World Scientific Publishing Company.