Readout and control of molecules for electric dipole moment searches

The observed imbalance between matter and antimatter is an important open question in fundamental physics. Processes that contribute to this imbalance must violate CP symmetry, a discrete symmetry that appears to be conserved for most processes in particle physics. There are several approaches in the search for CP violation. The work of Anno Touwen focuses on an approach using precision measurements on molecules. An energy difference is measured that can be traced back to the electric dipole moment of the electron (eEDM). For fundamental particles such as the electron, this property would violate CP, and therefore be a sign of the processes that contribute to the imbalance.

This energy difference that can be traced back to the eEDM is very small. There are many processes that cause a larger energy difference and can be interpreted falsely. In order to perform these precision measurements, a setup has been developed in which relevant parameters can be kept constant, while the electric field to which the eEDM is linked is varied. Touwen developed the data acquisition and control system for this experiment.

For a sensitive measurement, many molecules are needed, which can be studied for as long as possible. A molecule decelerator has been developed for this purpose, which causes molecules to move more slowly through the setup. Touwen demonstrated the deceleration of molecules that are sensitive to the eEDM. An electrostatic lens was used to get as many molecules as possible into the decelerator.

See also: Trapping molecules

Dissertation: https://hdl.handle.net/11370/09b9a760-d688-487a-a667-81c0d096837e