The Ions group studies fundamental interactions and symmetries. It uses the most precise tools currently available: trapping and cooling of ions, atoms, and molecules using lasers and other advanced tools. We need cold particles so that they are almost at rest. Particle properties can be measured very precisely then.
The particles are micro laboratories to search for minute deviations from properties predicted by the known forces of nature. In particular observing violation of mirror symmetry and time reversal symmetry is important. Where particle physicists look for new physics at high energy (CERN, Geneve), we can look for new physics in cold particles using precision tools.