Friday, September 19, 2008 3:15 pm Neils 224. (Note earlier time). Refreshments at 3:05 in same room.
Department of Physics
University of Washington
It is remarkable that small-scale experiments can address important open issues in fundamental science such as: "why is gravity so weak?" and "why is the cosmological constant so small?" String theory ideas (new scalar particles and extra dimensions) and other notions hint that Newton's Inverse-Square Law could break down at distances less than 1 mm. I will review the varied motivations for testing the Inverse-Square Law at the smallest achievable distances. Our experiments at separations down to 60 micrometers exclude gravitational-strength Yukawa interactions with length scales greater than about 56 micrometers (less than the diameter of a human hair), and set a robust 95% confidence upper limit of 44 micrometers on the size of an extra dimension. Problems encountered in probing hese short length scales will be discussed.