Abstract
In this work, an interacting chameleon-like scalar field scenario, by considering SNeIa, CMB, BAO, and OHD data sets, is investigated. In fact, the investigation is realized by introducing an ansatz for the effective dark energy equation of state, which mimics the behavior of chameleon-like models. Based on this assumption, some cosmological parameters, including the Hubble, deceleration, and coincidence parameters, in such a mechanism are analyzed. It is realized that, to estimate the free parameters of a theoretical model, by regarding the systematic errors it is better that the whole of the above observational data sets would be considered. In fact, if one considers SNeIa, CMB, and BAO, but disregards OHD, it maybe leads to different results. Also, to get a better overlap between the contours with the constraint $$\chi _\mathrm{{m}}^2\le 1$$ , the $$\chi _\mathrm{{T}}^2$$ function could be re-weighted. The relative probability functions are plotted for marginalized likelihood $$\mathscr {L} (\Omega _\mathrm{{m0}} ,\omega _1, \beta )$$ according to the two dimensional confidence levels 68.3, 90, and $$95.4\,\%$$ . Meanwhile, the value of the free parameters which maximize the marginalized likelihoods using the above confidence levels are obtained. In addition, based on these calculations the minimum value of $$\chi ^2$$ based on the free parameters of the ansatz for the effective dark energy equation of state is achieved.
Highlights
66 Page 2 of 15 ations attract much attention to investigate the dark energy concept
Interacting models which contain an external interaction between matter and scalar fields attract more attention
Such mechanisms are capable to suppress the fifth force and are in good agreement with observations. Using such a powerful mechanism we have found some cosmological parameters referring to the coincidence and deceleration parameters
Summary
66 Page 2 of 15 ations attract much attention to investigate the dark energy concept. A mechanism should exist suppressing the effect of the fifth force; such a mechanism is capable of reconciling strong coupling models with local experiments, as proposed by Khoury and Weltman [40,41] and separately, by Mota and Barrow [42], namely the chameleon-like model In this mechanism, one cannot choose an arbitrary Lagrangian for matter, Lm. To avoid a deviation of the geodesic trajectory, the author of [43] has shown that the best choices are Lm = P and Lm = −ρ, where P is the pressure and ρ is the energy density of matter; for more discussion we refer the reader to [44,45,46].
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