Boynton Over the past three years, this group has tested and refined a new type of torsion pendulum instrument to measure extremely small forces (torques). This technology sidesteps the current impediment to further increases in signal-to-noise ratio for torsion pendulum measurements--fiber temperature variations--and opens new possibilities for high-precision tests of gravity and related experiments. They plan to employ this instrumentation to carry out the test for non-Newtonian interactions.
Based on the measured performance of this prototype instrument and detailed calculations of the limiting systematic effects posed by Newtonian gravity, they find it possible to set an upper bound on the strength of any non-Newtonian potential with a range between 10 and 20 centimeters, that approaches 10-5 of the strength of ordinary gravity. This is more than an order of magnitude below existing experimental bounds at this range or any range of terrestrial dimensions. ***
