Progress towards atomic parity violation measurements in francium*

Low-energy precision tests of electro-weak physics keep playing an essential role in the search for new physics beyond the Standard Model. Atomic parity violation (APV) experiments measure the strength of highly forbidden atomic transitions induced by the exchange of Z bosons between electrons and quarks in heavy atoms. APV is sensitive to additional interactions such as leptoquarks, and provides complementary sensitivity to parity-violating electron scattering. Our group is working towards a measurement in francium, the heaviest alkali (Z=87), where the APV signal is about 18 times larger than in cesium. Since Fr has no stable isotopes, we have established an online laser trap at the ISAC radioactive beam facility at TRIUMF in Vancouver that can currently confine up to a million cold francium atoms at micro-Kelvin temperatures. I will report on our recent observation of the highly forbidden 7s-8s magnetic dipole transition and on our new highly efficient optical detection scheme which will bring observation of APV in reach.