Hochauflösende Messungen von magnetischen und elektrischen Dipolmomenten von Atomkernen über die Spinpräzession in sehr niedrigen Magnetfeldern
Zusammenfassung der Projektergebnisse
Following the recommendation of the DFG-Fachkollegium, we focussed our work on the search of the non-zero electric dipole moment (EDM) of 129Xe. An EDM is a charge asymmetry along the total angular momentum axis of a particle or system and is odd under both parity reversal (P) and time reversal (T). Assuming CPT conservation (C is charge conjugation), an EDM is a direct signal of CP violation (CPV), a condition required to generate the observed baryon asymmetry of the universe. As a result of our study, we could set a new upper limit in 129Xe EDM of |dA(129Xe)|< 1.4 x 10^-27 e cm (95% CL), which is a factor of five lower than the limit set in 2001. In the last few months after the end of the funding period, by a refined analysis, we were able to this limit by another factor of two, so that we have met the aim set in our proposal that “The present upper bound of the electric dipole moment in xenon is expected to be improved by at least an order of magnitude”. To reach this goal, we have improved our experimental set-up, and developed new approaches for data evaluation, as well as detailed analysis of potential impacts of systematic uncertainties. We want to emphasize that our project was performed in close collaboration with the group of Tim Chupp of the University of Michigan, who spent many weeks in our lab and held close contact with us during the project by regular web meetings.
