A new approach to high-precision measurements of the electron EDM using francium atoms*

Searching for the permanent electric dipole moment (EDM) of a particle leads to new physics beyond the standard model of particle physics. It is known that the electron EDM is enhanced in heavy paramagnetic atoms; for instance, francium (Fr) atoms, which can be produced by a fusion reaction between oxygen and gold. The electron structure of Fr atoms allows laser-cooling as well as trapping in an optical lattice where high-precision measurements of the electron EDM take place. The number of Fr atoms in an optical lattice is directly related to the precision of the measurements. Therefore, it is important to prepare a large number of Fr atoms in a magneto-optical trap (MOT) prior to transferring them to an optical lattice. Based on the results of trapping Fr atoms with an MOT at Tohoku University’s CYRIC facility, I will present updates on the development of an innovative new experimental apparatus being constructed at RIKEN’s RIBF facility. This new apparatus is designed to realize the largest number of Fr atoms ever trapped with an MOT.