CERN Accelerating science

Answering the question of why we live in a matter-dominated universe is of great interest to contemporary physicists, as the Standard Model of Particle Physics predicts that matter and antimatter should only ever be produced in equal parts. Antihydrogen is a good candidate for searches for asymmetries between matter and antimatter as it is the simplest antimatter bound state, and it has an extremely well-understood matter counterpart: the hydrogen atom.

The positron, the antiparticle of the electron, predicted by Dirac in 1931 and discovered by Anderson in 1933, plays a key role in many scientific and everyday endeavours. Notably, the positron is a constituent of antihydrogen, the only long-lived neutral antimatter bound state that can currently be synthesized at low energy, presenting a prominent system for testing fundamental symmetries with high precision.