More details can be found at

This project was supported 2012 -2017 by the ERC Advanced Grant 291242, see and 

Physical laws are believed to be invariant under the combined transformations of charge (C), parity (P), and time (T) reversal. This CPT symmetry implies that antimatter particles have exactly the same mass and charge as their particle counterparts. Within the ASACUSA program at the Antiproton Decelerator at CERN (CH), SMI is involved in the measurement of the ground-state hyperfine splitting of antihydrogen, the simplest antimatter atom consisting of a positron and an antiproton.