Atomic cesium embedded in cryogenic argon for electron EDM search

EDMs, i.e. electric dipole moments of electrons, neutrons or nuclei are sensitive probes for new physics beyond the Standard Model of particle physics. In the present project, we propose to measure the electron EDM using atoms embedded in a cryogenic solid matrix. Matrices offer unprecedented sample sizes while maintaining characteristics of an atomic physics experiment, such as the possibility of manipulation by lasers. We will present the EDMMA (Towards an Electric Dipole Moment with atoms and molecules in Matrix) project, that is a collaboration between experimental (LAC, ISMO,LPL) and theoretical (CIMAP) groups. We will present our first experimental and theoretical investigation of the spectroscopy of dilute cesium (Cs) atoms in a solid argon (Ar) matrix at cryogenic temperatures. The absorption spectra show evolution of the absorption peaks with temperature. Using the pairwise potentials we perform a trapping site stability and obtained reasonable agreement between observed and simulated absorption line positions and linewidths. We will also discuss recent fluorescence measurments. This should set the ground for further study of systematic effects that can occur for an EDM measurment.