Extra force in brane worlds - art. no. 084002

By carefully analyzing the geodesic motion of a test particle in the bulk o f brane worlds, we identify an extra force which is recognized in a spaceti me of one lower dimension as a nongravitational force acting on the particl e. Such extra force acts on the particle in such a way that the conventiona l particle mechanics in one lower dimension is violated, thereby hinting at the higher-dimensional origin of embedded spacetime in the brane world sce nario. We obtain the explicit equations describing the motion of the bulk t est particle as observed in one lower dimension for general gravitating con figurations in brane worlds and identify the extra nongravitational force a cting on the particle measured in one lower dimension.