Eot-Wash sub-mm test inverse square law

[marcus]

Last year the Eot-Wash group found no deviation from invers sq. at close range (on order 100 micron)

http://arxiv.org/abs/hep-ph/0405262
Sub-millimeter Tests of the Gravitational Inverse-square Law
C.D. Hoyle, D.J. Kapner, B.R. Heckel, E.G. Adelberger, J.H. Gundlach, U. Schmidt, H.E. Swanson
34 pages, 38 figures
Phys.Rev. D70 (2004) 042004

"Motivated by a variety of theories that predict new effects, we tested the gravitational 1/r^2 law at separations between 10.77 mm and 137 microns using two different 10-fold azimuthally symmetric torsion pendulums and rotating 10-fold symmetric attractors. Our work improves upon other experiments by up to a factor of about 100. We found no deviation from Newtonian physics at the 95% confidence level and interpret these results as constraints on"

Now, according to Motl there is gossip that they think they did find some shortrange deviation from Newton gravity inverse sq

the Eot-Wash group is highly respected. here is a webpage on who they are
http://www.npl.washington.edu/eotwash/
with photographs
http://www.npl.washington.edu/eotwash/people.html

Motl reports the gossip here
http://motls.blogspot.com/2005/06/deviations-from-Newtons-law-seen.html

the experimenters think (according to the rumor) that gravity at 100 micron distance is WEAKER than Newton law says

 

[ohwilleke]

Thanks for the links. Both the finding itself, and the rumors that gravity may be weaker than expected at small scales is very interesting. Tests like the Eot-Washington group ones are long overdue. The cost of that apparatus has to be a tiny fraction of that of ventures like the large hadron collider, but equally fundamental.