Solar System’s Bounds on the Extra Acceleration of f(R, T) Gravity Revisited

Abstract

As a generalization of Einstein’s general relativity (GR), the f(R, T) gravity replace the gravitational Lagrangian of GR with an arbitrary function of the Ricci scalar R and of the trace of the stress-energy tensor T. It can induce an extra acceleration a E in the dynamics of massive test particles due to the physical coupling between matter and geometry. In this work, we confront this extra acceleration with planetary motions in the solar system. Using the supplementary advances in the perihelia provided by current INPOP10a and EPM2011 ephemerides, we obtain new upper limits on a E when the uncertainty of the Sun’s quadrupole moment and the Lense-Thirring effect due to the Sun’s angular momentum are properly taken into account. These two factors were mostly absent in previous works dealing with a E. We find that INPOP10a yields the upper limit as a E=(−0.04±4.81)×10−15 m s −2 and EPM2011 gives a E=(0.06±1.58)×10−15 m s −2. Both of them are improved at least by about 10 times than previous results obtained in the solar system and they are smaller than the results given by fitting rotation curves of galaxies by about 4 orders of magnitude. This discrepancy of a E on these scales seems to imply that its effects might be screened in high density regions.