Peter Geltenbort Colloquium

Wed. Feb. 1 12:30 PM - Wed. Feb. 1 01:20 PM
Location: 1L07

Research with very cold and ultra-cold neutrons

Due to their outstanding property to be storable and hence observable for long periods of time (several hundreds of seconds) in suitable material or magnetic traps, ultra-cold neutrons (UCN) with energies around 100 neV are an unique tool to study fundamental properties of the free neutron, like its beta-decay lifetime, its electric dipole moment and its wave properties.

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. Precision measurements of the neutron lifetime provide stringent tests of the standard electroweak model as well as crucial inputs for tests of Big-Bang nucleosynthesis. Neutron lifetime can be related to CKM Matrix unitarity. Neutron lifetime also dominates the uncertainty in theoretical calculation of primordial 4He.

After the observation of quantum states of UCN in the gravitational potential of the Earth, a new powerful resonance spectroscopy technique has been established. It allows precision experiments as tests of the equivalence principle and Newton’s gravity law at the micrometer scale. In this talk, the ILL will be briefly introduced before recent ILL experiments linked to these fundamental questions are presented and a brief outlook is given.


About the speaker

Peter W.H. Geltenbort received a Ph D from the University of Tuebingen, Germany, in 1983. He joined the Nuclear and Particle Physics (NPP) College at the ILL in 1983 responsible for a fission fragment spectrometer. From 1989 to 1993 he held the position of Head of the Detector Group. In 1993 he reintegrated into the NPP College responsible for the Ultra-Cold Neutron/Very Cold Neutron facilities at the ILL. His current research interests are the fundamental properties of the neutron.