Professor Ho Jung Paik
Department of Physics, University of Maryland
"Probing Extra Dimensions and the Axion with a Superconducting Accelerometer"
Abstract: In string theories, the law of gravity changes as the distance /r/ is reduced to below the radius of compactification, /R/. Gravity-only large extra dimensions with /R/ ~ 100 /5/m could solve the gauge hierarchy problem in grand unification. Further, the axion, a dark matter candidate, may appear as a violation of the 1//r/^2 law slightly above 100 /5/m. We are conducting a sub-millimeter test of the 1//r/^2 law at 4.2 K. To minimize Newtonian errors, the experiment employs a near-null source, a circular disk of large diameter-to-thickness ratio. Two test masses, also disk-shaped, are positioned on the two sides of the source mass at a nominal distance of 250 /5/m. The test masses are connected to a SQUID to form a superconducting differential accelerometer. As the source mass is driven sinusoidally, a violation signal should appear at the second harmonic due to symmetry. In this talk, we will discuss the experimental technique and report the progress of the experiment.
Location: Physics/Astrophysics Building, Conference Rooms 102 & 103
Thursday, November 6, 2008, 2:45 pm - 4:00 pm
Light refreshments available 2:30 pm; Presentation begins 2:45 pm. Open to all.
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