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Prof. John Doyle is spokes person of the ACME collaboration for the determination of the EDM of the electron. He will give a presentation at NIKHEF on the recently obtained new upper limit on the EDM. You are cordially invited for this presentation.

Detail Summary
Date 26 November 2018
Time 14:00 - 15:00


The standard model of particle physics accurately describes all particle physics measurements made so far in the laboratory. However, it is unable to answer many questions that arise from cosmological observations, such as the nature of dark matter and why matter dominates over antimatter throughout the Universe. Theories that contain particles and interactions beyond the standard model, such as models that incorporate supersymmetry, may explain these phenomena. Such particles appear in the vacuum and interact with common particles to modify their properties. For example, the existence of very massive particles whose interactions violate time-reversal symmetry, which could explain the cosmological matter–antimatter asymmetry, can give rise to an electric dipole moment along the spin axis of the electron. No electric dipole moments of fundamental particles have been observed. However, dipole moments only slightly smaller than the current experimental bounds have been predicted to arise from particles more massive than any known to exist. Here we present the latest results of the ACME II experiment, an improved experimental limit on the electric dipole moment of the electron, obtained by measuring the electron spin precession in a superposition of quantum states of electrons subjected to a huge intramolecular electric field. The sensitivity of our measurement is more than one order of magnitude better than the previous best measurement, ACME I, also done in our labs. This result implies that a broad class of conjectured particles, if they exist and time-reversal symmetry is maximally violated, have masses that greatly exceed what can be measured directly at the Large Hadron Collider. Future directions for EDM experiments using the latest quantum tools will also be discussed, with prospects for broadly sensitive experiments probing the PeV range of new physics.

Locatie: Hall H.331 at NIKHEF, Science Park 105 (