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

TL;DR

This paper uses Lunar Laser Ranging data to test the equivalence of active and passive gravitational mass for Aluminium and Iron, setting a new limit that is significantly more precise than previous measurements.

Contribution

It provides the most stringent test to date of the equality of active and passive gravitational mass using decades of LLR data.

Findings

New limit of $3.9\times10^{-14}$ on mass equivalence violation

Improved precision by about 100 times over previous studies

Demonstrates the effectiveness of long-term LLR data in fundamental physics tests

Abstract

LLR measures the distance between observatories on Earth and retro-reflectors on Moon since 1969. In this paper, we study the possible violation of the equality of passive and active gravitational mass ($m_{a}/m_{p}$), for Aluminium (Al) and Iron (Fe), using LLR data. Our new limit of $3.9\cdot10^{-14}$ is about 100 times better than that of Bartlett and Van Buren [1986] reflecting the benefit of the many years of LLR data.