TRIUMF - Canada’s National Lab for Particle and Nuclear Physics
Thursday, April 27, 2017
Antihydrogen is the antimatter counterpart of atomic hydrogen, and consists of an antiproton and a positron. Antihydrogen atoms were first produced at relativistic speeds in the 1990s by Bauer et al. at CERN, and by Blanford et al. at Fermilab. 20 years since these pioneering observations, tremendous technical progress has been made in creating, manipulating, and studying anti-atoms. The ALPHA (Antihydrogen Laser Physics Apparatus) experiment is an international project located at CERN. Its goal is to test symmetries between matter and antimatter via precision comparisons of the properties of antihydrogen with its well-studied hydrogen counterpart. In particular, ALPHA is confronting both CPT (Charge, Parity, and Time-reversal) symmetry and the Weak Equivalence Principle, two of the most fundamental underpinnings of Quantum Field Theory and General Relativity, respectively. Any measured violation of them would force a radical change in the way we understand Nature. Recently, the ALPHA Collaboration has succeeded in observing, for the first time, laser induced transitions in trapped antihydrogen. The initial measurement had a sensitivity of parts per 10 billion, and we expect significant improvements in the near future. In the meantime, we are constructing a new apparatus, ALPHA-g, in order to measure the gravitational force on antimatter by dropping antihydrogen atoms. In this talk, I will give an overview and prospects of the ALPHA experiment.