Neutron Electric Dipole Moment searches at the ILL
Dr. Maurits van der Grinten (Rutherford Appleton Laboratory / University of Sussex, UK)

The search for the electric dipole moment (EDM) of the neutron plays a prominent role in particle physics because of its direct bearing on CP and T violation: a non-zero value of the neutron EDM would be evidence of CP and T violation.
In this talk two EDM projects will be presented, an experiment at room temperature that has recently been completed and a cryogenic experiment that is currently being constructed. The experiments are based on a precision measurement of the Larmor precession frequency of polarised ultracold neutrons stored in a cell in a magnetic field. An EDM would reveal itself by a response of the Larmor precession frequency of the neutron to an electric field applied over the storage volume.
In the room temperature EDM experiment data has been taken over a period of six years and it has subsequently been running for one year devoted to systematic studies related to the experiment. The experiment has resulted in an EDM measurement with a sensitivity of the order of 10^-26 ecm. The cryogenic experiment, that will be operational in this summer, aims at pushing this limit further by an order of magnitude initially.
The experimental techniques used in the experiments will be discussed, along with an overview of the new superthermal UCN source set-up and its performance. The systematic studies and the data analysis of the room temperature experiment will also be addressed.