A New Multi-mode Apparatus to Determine G

Of all the fundamental constants in nature, G, the Newtonian gravitational constant, is known with the least precision. The world's best experiments yield values which are incompatible with one another and differ by about 50 times the uncertainty of the most precise experiment. Two recent experiments have, however, obtained consistent results at the 12 ppm level. Since it is possible that a portion of the past discrepancies between determinations of G can be traced back to the methodology used, the research group at IUPUI, in collaboration with Humboldt State University and Syracuse University, will combine different approaches to determine G within the same torsion pendulum apparatus. We expect to obtain a measurement of G at the 2 ppm level from each method. With the experiments carried out in the same apparatus, the effort will also help to understand the current discrepancies among existing experimental results. This talk will explore the experimental configurations as well as give a general status update on this relatively new project.