Constraining massless dilaton theory at Solar system scales with the planetary ephemeris INPOP

TL;DR

This paper tests the massless dilaton theory in the Solar system by analyzing planetary ephemeris data to constrain the coupling constants of the theory, providing the first such constraints at this scale.

Contribution

It derives modified equations of motion for the dilaton theory and constrains the coupling parameters using INPOP19a planetary ephemeris data.

Findings

Constraints on the coupling constants: _0, _T, _G.

Successful testing of the linear coupling scenario.

Constraints at 99.5% confidence level.

Abstract

We expose the phenomenology of the massless dilaton theory in the Solar system for a non universal quadratic coupling between the scalar field which represents the dilaton, and the matter. Modified post-Newtonian equations of motion of an $N$-body system and the light time travel are derived from the action of the theory. We use the physical properties of the main planets of the Solar system to reduce the number of parameters to be tested to 3 in the linear coupling case. In the linear case, we have an universal coupling constant $\alpha_0$ and two coupling constants $\alpha_T$ and $\alpha_G$ related respectively to the telluric bodies and to the gaseous bodies. We then use the planetary ephemeris, INPOP19a, in order to constrain these constants. We succeeded to constrain the linear coupling scenario and the constraints read $\alpha_0=(1.01\pm23.7)\times 10^{-5}$, $\alpha_T=(0.00\pm24.5)\times 10^{-6}$, $\alpha_G=(-1.46\pm12.0)\times 10^{-5}$, at the 99.5 \% C.L.