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Table-top precision measurements to test fundamental physics

Hessels Fundamental physics, including physics beyond the Standard Model, can be tested using table-top precision measurements. The talk will describe three such high-precision measurements: the size of the proton, the fine-structure constant and the electric dipole moment of the electron.

For the first measurement, the n=2 Lamb shift of atomic hydrogen is measured, allowing for a new determination of the charge radius of the proton. This determination is crucial to resolving the eight-year-old proton radius puzzle , in which it appeared that the proton radius took on a different value when measured with muons compared to measurements using electrons.

The second measurement is of the n=2 triplet P fine structure of atomic helium, and this work is part of a program to obtain a new determination of the fine-structure constant to better than 1 part per billion.

Finally, a new major effort (EDM 3 ) is starting at York University to measure the electron electric dipole moment using molecules embedded into inert-gas solids. This measurement will test for time-reversal symmetry (T) violation and will probe physics up to the PeV energy scale.