Probing the matter-antimatter-asymmetry problem using precision spectroscopy of positronium

Project ID: 2228cd1411 (You will need this ID for your application)

UCL Lead department: Physics and Astronomy

Project Summary:

The Standard Model has passed (almost) every test with flying colours, and we have seen great advances in astronomy, cosmology and particle physics, including observation of Dark Matter, and the accelerating expansion of the Universe, and the detection of the Higgs Boson. At the same time, we have no idea what Dark Matter is, we don’t know how the expanding Universe can be accelerating, and as far as we know the Big Bang cannot produce a matter dominated Universe, even though it evidently has. The matter we can directly see in space constitutes less than 5% of the energy content of the Universe, and half of that is apparently missing. There are numerous efforts going on around the world to try and understand these and other significant fundamental problems in physics. This project is directed towards the matter-antimatter asymmetry problem. We expect matter and antimatter to be precisely symmetric, which makes creating an asymmetric Universe almost impossible under our current understanding of physics. If, however, there is some sort of unexpected difference between the properties of matter and antimatter then this could provide a mechanism for the Universe to evolve as it has, and also (as a side benefit) for us humans to exist. In the positronium spectroscopy group at UCL we aim to search for such differences using the atomic system called positronium (Ps). This is an exotic atom made from a positron and an electron, which should be well-described by QED theory. Precision microwave or laser spectroscopy can therefore be used to check for anomalies that might arise from matter-antimatter asymmetry. We are looking for enthusiastic physicists to join our team and help us perform these sensitive measurements. Experience with vacuum systems, lasers, microwave radiation sources, radiation detectors, or PYTHON coding would be advantageous, but is not essential.