Seminar at the Université de Genève
Ecole de physique - Département de physique nucléaire et corpusculaire
24, Quai Ernest-Ansermet
1211 GENEVE 4
Tél: (022) 379 62 73 - Fax: (022) 379 69 92
Wednesday 14 November 2007
PARTICLE PHYSICS SEMINAR
at 17.00 hrs – Stückelberg Auditorium
Towards a measurement of the neutron electric dipole moment at PSI
by Dr Klaus Kirch - PSI, Villigen
The electric dipole moment of the neutron (nEDM) has been searched for since the 1950s, improving the experimental sensitivity over the years by more than 6 orders of magnitude. A finite value of the nEDM would violate parity and time reversal symmetry and - invoking the CPT theorem - also CP. CP-violation, additional to the one known already, is needed in order to explain the observed baryon asymmetry of the universe. While in the electro-weak part of the Standard Model the nEDM is still another 6 orders of magnitude below the experimental limit, the strong interaction as well as, e.g. supersymmetric, extensions of the Standard Model foresee large CP-violation, and possibly lead to a finite nEDM. The nonobservation of the nEDM therefore lead to the " strong CP problem" and the "susy CP problem".
The progress to set up a new source of ultracold neutrons at PSI and the planned improved search for the nEDM at this source is described. As a byproduct, the first direct experimental limit on neutron -- mirror-neutron oscillations has been recently measured and will be reported.
Organizer: J.-S. Graulich