Non-geodesic motion in f (G) gravity with non-minimal coupling

The dynamics of test particles in f(g) modified Gauss-Bonnet gravity is investigated. It is shown that in f(g) gravity models with non-minimal coupling to matter, particles experience an extra force normal to their four-velocities and as a result move along non-geodesic world-lines. The explicit form of the extra force depends oil the function of the Gauss-Bonnet term included in coupling term. The effects of this force oil the relative accelerations of particles are studied. (C) 2009 Elsevier B.V. All rights reserved.