Applied Physics/Physics Colloquium: Order of Magnitude Smaller Limit on the Electric Dipole Moment of the Electron

Order of Magnitude Smaller Limit on the Electric Dipole Moment of the Electron
Tuesday, November 18, 2014 - 4:15pm to 5:15pm
Hewlett 201
John Doyle (Harvard University)
Abstract / Description: 

The Standard Model (SM) of particle physics is known to be incomplete. Extensions to the SM, such as weak-scale Supersymmetry, posit the existence of new particles and interactions that are asymmetric under time-reversal (T), and nearly always predict a small, yet potentially measurable (10-27-10-30 electron electric dipole moment (EDM, de). The EDM is an asymmetric charge distribution along the spin that is also asymmetric under T.

About five years ago, ACME, a collaboration between groups at Yale and Harvard Universities (, embarked upon an improved search for the electron EDM. Using the polar molecule thorium monoxide (ThO), we have now measured de =(-2.1+-3.7stat +-2.5syst) X 10-29 This corresponds to an upper limit of |de| < 8.7 X 10-29 with 90 percent confidence, an order of magnitude improvement in sensitivity compared to the previous best limits. Our result constrains T-violating physics and SUSY theories at the TeV energy scale. This experiment was accomplished using a new cold beam source, new molecule and new approach. We are continuing to improve our experiment and updates on recent progress will be presented.

 Held Tuesdays at 4:15 pm, in the William R. Hewlett Teaching Center, room 200 (see map). Refreshments in the lobby of Varian Physics at 4:00 pm.

Autumn 2014/15, Committee: A. Linde (Chair), L. Hollberg, B. Macintosh & Young Lee