The γ parameter in Brans-Dicke-like (light-)Scalar-Tensor theory with a universal scalar/matter coupling

Abstract

The post-Newtonian parameter γ resulting from a universal scalar/matter coupling is investigated in Brans-Dicke-like Scalar-Tensor theories where the scalar potential is assumed to be negligible. Conversely to previous studies, we use a perfect fluid formalism in order to get the explicit scalar-field equation. It is shown that the metric can be put in its standard post-Newtonian form. However, it is pointed out that 1-γ could be either positive, null or negative for finite value of ω_0, depending on the coupling function; while Scalar-Tensor theories without coupling always predict γ<1 for finite value of ω_0.

6 pages, accepted in Phys. Rev. D. arXiv admin note: substantial text overlap with arXiv:1208.2372

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Cited by in corpus (5)

• Generalized curvature-matter couplings in modified gravity
• Late-time cosmology of scalar-tensor theories with universal multiplicative coupling between the scalar field and the matter Lagrangian
• Post-Newtonian parameter $\gamma$ for multiscalar-tensor gravity with a general potential
• Merging matter and geometry in the same Lagrangian
• On the cosmic convergence mechanism of the massless dilaton