Ultracold eEDM: a new experiment to measure the electron's electric dipole moment using ultracold moelcules

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The visible Universe contains hardly any antimatter, but plenty of matter. The known fundamental forces barely distinguish between matter and antimatter so there must be undiscovered forces that account for this asymmetry. These new forces must influence the shapes of the fundamental particles, making them slightly aspherical. Measuring this distortion - known as the electric dipole - will reveal the existence and nature of the new forces. So far, measurements have detected only spherical particles, showing that their electric dipoles are exceedingly small. We aim to determine the shape of the electron by measuring the tiny interaction energy of the electric dipole with an applied electric field. This energy is enhanced when the electron is bound up in a polar molecule, an effect of special relativity. We will use a gas of ytterbium fluoride molecules, whose enhancement factor is a million, cooled to a temperature of 50 microkelvin. This deep cooling is a new technological advance that will make our measurement hundreds of times more sensitive than previous experiments. We will be sensitive to fundamental forces lying far beyond the energy range of the Large Hadron Collider, but we will not need a particle collider - the experiment will be done in a small laboratory in London. In the first two years, we will design and build the apparatus needed to make the measurement. Then we will optimize each part of the apparatus, and demonstrate that it is sensitive to the shape of the electron at the anticipated level. Finally, we will investigate potential systematic errors in the experiment - effects that might mimic the signature of an electric dipole - and eliminate these errors so that the experiment is perfected.