Physics with antiparticles is difficult, but one trick is to replace atomic electrons by antiprotons. The resulting compact atoms are useful antiparticle laboratories.
A major antiproton experiment at CERN's Antiproton Decelerator is currently lining up an impressive array of techniques to investigate the interaction of antiprotons with atoms.
After a three-year pause, antiproton physics gets under way later this year at CERN using the new Antiproton Decelerator ring. These articles look at the AD and its physics programme.