Positronium is an ideal system for research on QED, especially in a bound state. A discrepancy (3.9s) is found recently between measured HFS values and the QED prediction (including up-to O(α 3 log α -1), where a is the fine-structure constant.). It might be due to a contribution of unknown new physics or common systematic problems in all the previous measurements. A new method to measure HFS directly is performed using a high power gyrotron. The transition from ortho-positronium to para-positronium has been observed with 5 σ CL, which is the first observation of M1 transition in (sub)Terahertz region. New technologies of high power gyrotrons are developed for precision spectroscopy.
|Number of pages
|Journal of Infrared, Millimeter, and Terahertz Waves
|Published - Jul 2012
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Electrical and Electronic Engineering