Fundamental Tests with Antihydrogen Atoms


Professor Joel Fajans, UC Berkeley
This colloquium will be held 12 noon, 21st July, in Parnell 07-222

Motivated by the baryogenesis problem (the scarcity of antimatter in the University), CERN’s ALPHA collaboration has been studying the properties of antihydrogen atoms. Since 2010, we have been able to trap nearly 10000 antiatoms, and have kept some trapped for as long as 1000s. We have measured the spin flip frequency of these antiatoms to 0.1%, and the charge of the antiatoms to 0.7ppb; both of these studies search for CPT violations. Just recently, we were able to determine the 1s-2s transition energy by illuminating antiatoms held within a 243nm laser cavity. At an accuracy of 200ppt, this is, by some measures, approaching the most precise CPT tests. We have also set crude bounds on the gravitational properties of these antiatoms (antimatter g limited by +/-100g), and are constructing a new apparatus designed to measure the antimatter g to 1%; this is a test of the weak equivalence principle. This talk will describe how we trap antihydrogen, and discuss our physics results.