Speaker
Andrzej Czarnecki
(U. Alberta)
Description
The mass of the electron is best determined with hydrogen-like ions in a Penning trap. Binding in an ion removes the error due to the thermal motion of the electron. However, the price is that some properties of the electron are modified by the binding. These changes can be computed in QED but there are interesting complications. We present recent progress in the determination of the g-factor of a bound electron. This calculation is motivated by the 2014 improvement in the mass of the electron and makes further experimental progress possible.
We also report an improved determination of the electron spectrum in the decay of a bound muon. This study is motivated by the upcoming experiments Mu2e (Fermilab) and COMET (J-PARC) that will search for the exotic muon-electron conversion, in an effort to discover the non-conservation of the charged lepton flavor. High-energy electrons produced in the ordinary decays of muons are a background in these searches. In these experiments muons are stopped in an aluminium target. Thus, we have determined the modification of the decay spectrum by the Coulomb field of a Z=13 nucleus.
Author
Andrzej Czarnecki
(U. Alberta)