An overview is givenon our recentmeasurements with extreme precision on single or few cooled ions stored in Penning traps. On the one hand, mass measurements provide crucial information for atomic, nuclear and neutrino physics as well as for testing fundamental symmetries. On the other hand, g-factor measurements of the boundelectron in highly-charged hydrogen-like ions allow for the determination of fundamental constants and for constraining Quantum Electrodynamics. For example,the most stringent test of CPT symmetry in the baryonic sectorcould be performed by mass comparison of the antiproton with H- and the knowledge of the electron atomic mass could be improved by a factor of 13.
Biosketch：Klaus Blaum received his PhD in 2000 at the University of Mainz. After a four-years stay at CERN, he moved back to Mainz to lead a Helmholtz-Young-Investigator Group. In 2007, he became director at the Max-Planck-Institute for Nuclear Physics in Heidelberg, heading the Division on “Experiments with Stored and Cooled Ions”. He is member of the Physics Faculty of the University of Heidelberg. Klaus Blaum has received numerous awards, among them the Helmholtz-Prize, the Flerov-Medal and the Gothenburg Lise Meitner Award.