Michael Heiss (ETH Zurich (CH))
Positronium is an excellent system to test bound state QED theory to very high precision, since it is almost exlusively governed by the electro-magnetic force and does not exhibit finite size effects. Numerous precise experiments have therefore been conducted in the past to measure the fine and hyperfine splitting. However, some experiments show disagreements of up to 4.5σ with most recent calculations. Furthermore, a new precision measurement of the 1S-2S transition would allow for a stringent test of QED theory in the ppb range. This talk will report on the current status of efforts at ETH Zurich to measure the 1S-2S and excited state fine and hyperfine splitting in Positronium.
Michael Heiss (ETH Zurich (CH)) Lucas de Sousa Borges (ETH Zurich) Anna Soter (ETH Zürich) Paolo Crivelli (ETH Zurich (CH))