Quantum gravity: Observational constraints on a pair of Yukawa terms

Measurements of gravity in mines that indicate the existence of a very weak intermediate-range force, causing a mutual repulsion of masses at separations up to 1 or 2 km, are used to examine the possibility that we are observing not a single force but a small difference between two forces, each comparable to normal gravity but of opposite signs. Constraints are imposed also by satellite and lunar reflector data and by measurements of the gravitational constant using a hydroelectric reservoir. Ranges of the opposing forces up to 450 km are permitted, provided the repulsive force is stronger by about 1% of gravity and its range is slightly shorter than that of the attractive force. If the forces are baryon-number dependent then gravity differences apparent in the von Eötvös data for various materials are also compatible with these conclusions