Session D9 - Experimental Tests of Short Range Gravitation.
ORAL session, Saturday afternoon, May 01
Governor's Square 12, Adam's Mark Hotel
We are testing the weak equivalence principle using a rotating torsion balance. A composition dipole, consisting of titanium and beryllium, is suspended form a torsion fiber. The whole torsion balance is rotated with a constant angular velocity about the fiber axis. A violation of the equivalence principle would result in a periodic differential acceleration of the two materials directed towards a large variety of sources. We will be able to test the equivalence principle for ranges from ~1m to infinity. In particular we can test for differential accelerations between the two different materials toward the center of our galaxy. Since about 25% of the acceleration towards the center of the galaxy is caused by dark matter, this measurement allows us to test for the equivalence principle for the galactic dark matter. We expect to achieve a differential acceleration sensitivity of 1\times\;10^-15\; \mboxm/\mboxs^2, which will allow us to test the equivalence principle for galactic dark matter at the 10^-4 level.