Testing CPT symmetry with antiprotonic helium and antihydrogen

The ASACUSA collaboration is performing precision laser and microwave spectroscopy of exotic atoms containing an antiproton at the Antiproton Decelerator (AD) of CERN, Geneva, Switzerland. The laser and microwave spectroscopy of antiprotonic helium, a three-body system containing an antiproton, a helium nucleus, and an electron, has - through comparison to state-of-the-art three-body QED calculations - yielded the most precise determination of the antiproton charge and mass. As a next major project, ASACUSA is pursuing a measurement of the ground-state hyperfine structure of antihydrogen, a quantity that is know for hydrogen to very high precision. These measurements constitute some of the best test of the fundamental CPT theory in the hadronic sector.