The Eöt-Wash Group:
Laboratory Tests of Gravitational and sub-Gravitational Physics
Results
| The plot on the right shows 95% confidence limits on equivalence-principle-violating Yukawa interactions as a function of Yukawa range. This plot assumes that the interaction couples to baryon number, a conservative case where all test bodies have very similar "charge"/mass ratios. | 
(click for
enlarged image) |
defined so that the Yukawa
force has a strength relative to gravity of × 
where (which has a numerical value
of about 2 × 10-3) measures the difference in "charge"/mass
ratios of the test bodies. For long ranges, the force sensitivity is about
1 × 10-12 of gravity. We now have obtained differential
acceleration sensitivities of about 4 × 10-13 cm/s2.
One can appreciate how small this is by noting that if an object,
initially at rest, had maintained that acceleration since the time of
Pericles, it would now be moving about as fast as the end of the minute
hand on a standard wall clock. |
This plot shows the 95% confidence level constraints on a Yukawa violation of the gravitational inverse-square law (as of 1/17/02). The vertical axis represents the strength of a deviation relative to that of Newtonian gravity while the horizontal axis designates its characteristic range. The yellow region has been excluded. The region excluded by our experiments has been updated since the publication of our paper . These results include an improved analysis of the published data, as well as data from an additional experiment. |  |
|
The results constrain
extra dimensions to be smaller than 150 um, for the particular case that
there are two large extra dimensions of equal size (see the paper by
Arkani-Hamed, Dimopoulos,
and Dvali for more information). A detailed description of this
analysis and its implications is given in our paper.
The dashed curve represents the area of parameter space we
will be able to explore with our next-generation apparatus within the near
future. References for the various theoretical and experimental curves can
be found in our paper
. |
© 1987-2008 Eöt-Wash Group. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation, DOE or NASA. Trouble? Comments? Contact cah49#at#u.washington.edu