SMI Seminar on fundamental interactions and symmetries

Positronium precision spectroscopy: Measurement of the 1S-2S and excited state fine and hyperfine transitions

by Michael Heiss (ETHZ - ETH Zurich)



Positronium is an excellent system to test bound state QED theory to very high precision, since it is almost exclusively 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 multiple transitions this system. 

However, some experiments show disagreements of more than 4σ with most recent calculations. Furthermore, new precision measurements of the 1S-2S and excited state fine and hyperfine splitting would not only allow for stringent tests of QED theory to current theoretical precision, but also to test CPT invariance complementary to measurements in hydrogen. 

This talk will report on past results obtained at ETH Zurich measuring the 1S-2S transition and current efforts to measure the fine and hyperfine splitting in Positronium.

Stefan Meyer Institute
Kegelgasse 27, 1030 Wien, Austria
Seminar Room 3.01, 3rd floor

Online Participation:
please request zoom link via email to martin.simon at
before 12:00 of June 22nd