Direct measurement of the positronium hyperfine interval using millimeter waves

by Akira Miyazaki (Department of Particle Physics-University of Tokyo)

Thursday 10 Jul 2014, 14:30 → 15:30 Europe/Zurich

26-1-022 (CERN)

I studied millimeter-wave spectroscopy of the positronium hyperfine structure for a QED test in the University of Tokyo.
I developed novel devices to produce high-power millimeter waves to directly induce the magnetic dipole transition from ortho-positronium to para-positronium.
I directly"determined the value of the hyperfine interval as 203.30+0.15/-0.19 (stat.) +/-0.11 (syst.) GHz for the first time.
There are indirectly obtained values from precise measurements of the Zeeman shifted levels in a static magnetic field of about 1 T.
This indirect measured value significantly differs from the QED calculation (alpha^3) by 15 ppm (3.9 sigma).
The direct measurement, albeit less accurate now because it is the first trial, has a potential to examine this problem without systematic uncertainties from the use of the static magnetic field.
 

Slides AkiraMiyazaki.pdf