Equivalence of Active and Passive Gravitational Mass Tested with Lunar Laser Ranging

Abstract

Lunar Laser Ranging (LLR) measures the distance between observatories on Earth and retro-reflectors on the Moon since 1969. In this Letter, we study the possible violation of the equivalence of passive and active gravitational mass (m_{a}/m_{p}), for aluminum (Al) and iron (Fe), using LLR data. Our new limit of 3.9×10^{-14} is about 100 times better than that of Bartlett and Van Buren [Equivalence of Active and Passive Gravitational Mass Using the Moon, Phys. Rev. Lett. 57, 21 (1986)PRLTAO0031-900710.1103/PhysRevLett.57.21] reflecting the benefit of the many years of LLR data.