Thursday, October 8, 2020, 16:00
WHGA Auditorium
Philipp Schmidt-Wellenburg, PSI
Abstract:
A nonzero permanent electric dipole moment (EDM) of a non-degenerate
particle with spin implies the violation of time-reversal symmetry.
Invoking the CPT theorem this also indicates the violation of the
combined symmetry of charge conjugation and parity (CP). We present the
result of an experiment to measure the EDM of the neutron at the Paul
Scherrer Institute using Ramsey's method of separated oscillating
magnetic fields with ultracold neutrons. The salient features of this
experiment were the use of a 199Hg co-magnetometer and an array of
optically pumped cesium vapor magnetometers to cancel and correct for
magnetic field changes. The statistical analysis was performed on
blinded datasets by two separate groups while the estimation of
systematic effects profited from an unprecedented knowledge of the
magnetic field.