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Physics and Astronomy

Physics & Astronomy Colloquium

3:30 PM, Friday, October 2, 2009
Room 155, Chem-Phys Building

Dr. Wolfgang Korsch
Department of Physics and Astronomy
University of Kentucky

"The Quest for a Permanent Electric Dipole Moment''

The existence of a permanent electric dipole moment (EDM) in any non-degenerate system is an affirmation of time- and parity-violation in fundamental interactions. The revelation of a non-zero EDM in next generation experiments on atoms, molecules, or neutrons would yield important information on physics beyond the Standard Model. Its discovery potential can be connected to the detection of supersymmetric particles at the LHC.

In the nuclear sector the most stringent limit on a permanent EDM was recently achieved at the University of Washington with a value of 3.1x10-29 e-cm for Hg-199. We are in the process of developing a new EDM search based on laser-cooled and trapped Ra-225 atoms. Due to octupole deformation of the nucleus, Ra-225 is expected to be significantly more sensitive to T-violating interactions than Hg-199.

The experimental sensivity to the neutron EDM has been improved by eight orders of magnitude over the last six decades. At present, the best limit of 2.9x10-26 e-cm was achieved at the Institut Laue-Langevin (ILL) using ultra-cold neutrons in a magnetic trap. A new experiment with the goal to improve this limit by possibly two orders of magnitude is under construction at the Spallation Neutron Source (SNS) in Oak Ridge. A dense target of ultra-cold neutrons, ``stored in a box,'' in combination with a novel detection technique will be used to accomplish this goal.

The present status of these experiments and the technology to achieve these objectives will be discussed.

Refreshments will be served in CP 179 at 3:15 PM