Cassini and extra force constraints to nonminimally coupled gravity with screening mechanism

TL;DR

This paper investigates a nonminimally coupled gravity theory at Solar System scales, analyzing extra forces and screening mechanisms to ensure consistency with Cassini measurements of gravitational parameters.

Contribution

It introduces a detailed analysis of nonminimal coupling effects and screening mechanisms in Solar System gravity, extending previous models to include the Sun's dynamical influence.

Findings

Conditions for screening of extra forces via chameleon mechanism

Constraints on nonminimal coupling from Cassini PPN parameter γ

Impact of Sun's dynamics on force behavior

Abstract

We consider a nonminimally coupled curvature-matter gravity theory at the Solar System scale. Both a fifth force of Yukawa type and a further non-Newtonian extra force that arises from the nonminimal coupling are present in the solar interior and in the solar atmosphere up to interplanetary space. The extra force depends on the spatial gradient of space-time curvature R. The conditions under which the effects of such forces can be screened by the chameleon mechanism and be made consistent with Cassini measurement of PPN parameter $\gamma$ are examined. This consistency analysis requires a specific study of Sun's dynamical contribution to the arising forces at all its layers.