Direct Measurement of Positronium Hyperfine Splitting - Testing Fundamental Physics with sub-THz Gyrotron

摘要

The direct transition from o-Ps to p-Ps was firstly observed, using a gyrotron, a mode-converter and a Fabry-Perot cavity. The Einstein's A coefficient is measured as 3.9 (+1.8 -1.7) · 10~(-8) s~(-1). It is the first step to directly examine a reported discrepancy of positronium hyperfine splitting.