Supervisors: Jony Hudson, Mike Tarbutt, Ben Sauer, Ed Hinds

Measuring the electron electric dipole moment in a molecular fountain.

One of the biggest mysteries in physics today is the remarkable imbalance between matter and antimatter. Almost everything in the Universe is made of matter- you, your computer and, as far as we can tell, all the stars and planets. Antimatter is present in only tiny quantities even though it seems to obey exactly the same laws of physics. Why should the Universe be able to choose to be made of matter, not antimatter? To help answer this question physicists are trying to make the most sensitive measurement of the shape of the electron. Any deviation from a perfect sphere would indicate an imbalance between the laws of physics and help to explain this difference.

In the Centre for Cold Matter we use a diatiomic molecule called YbF to make this measurement. Using this molecule actually enhances the asymmetry of the electron and makes it easier for the experimental physicists to find. However, because this asymmetry is extremely small (our current precision is equivalent to measuring the width of the solar system to better than the width of one human hair) we have to think of innovative ways to improve the precision of our measurement technique.

We can increase the sensitivity of our measurement by increasing the number of YbF molecules that participate in the experiment and by increasing their detection probability. Using laser, microwave and rf fields we propose to increase both the initial population via combined optical/rf pumping as well as the number of scattered photons in the probe region. Combined with existing improvements, the statistical uncertainty of our measurement will be reduced by a factor of 90, enabling us to search for an EDM below the recent upper limit of 8.7×10^-29

For more information see:

You can also follow us on twitter @YbFeEDM


Sensitivity improvements to the YbF electron electric dipole moment experiment, QuAMP Summer School, Durham, September 2014

Sensitivity improvements to the YbF electron electric dipole moment experiment, ICAP, Washington, August 2014

Improving the sensitivity of the electron electric dipole moment measurement, QuICC Summer School Imperial College London August 2013