Bonn 2010 – wissenschaftliches Programm
HK 27.2: Gruppenbericht
Dienstag, 16. März 2010, 17:00–17:30, HG V
A new measurement of the neutron electric dipole moment — •Johannes Zenner — Paul Scherrer Institut, Villigen, Switzerland — Johannes Gutenberg Universität, Mainz, Germany
A non-zero value of a neutron electric dipole moment (nEDM) would violate both time (T) and parity (P) symmetry. The present experimental upper limit is dn < 2.9·10−26 e·cm.
A collaboration of 15 European institutes aims at a sensitivity of 5·10−28 e·cm. This will allow probing much of the parameter space for super symmetric theories while it is still far away from the prediction of the electroweak standard model.
Currently an improved version of the former ILL-RAL-Sussex experiment is set up at the new powerful source for ultra cold neutrons (UCN) at the Paul Scherrer Institut, Switzerland. The improvements together with a higher UCN density will already yield a sensitivity of 5·10−27 e·cm. At the same time a new experiment is designed by the collaboration to have superior control over systematic effects, in particular with respect to magnetic fields. One such effect, the influence of Johnson-Nyquist noise that arises in metallic electrodes, and possible solutions to that problem will be presented in more detail. The status of the experiment will be discussed along with the progress for the new apparatus.