MEASURING THE ANTIHYDROGEN LAMB SHIFT WITH A RELATIVISTIC ANTIHYDROGEN BEAM

We propose an experiment to measure the Lamb shift and fine structure (the intervals 2s(1/2)-2p(1/2), and 2p(1/2)-2p(3/2)) in antihydrogen. A sample of 10 000 antihydrogen atoms at a momentum of 8.85 GeV/c suff ices to measure the Lamb shift to 5% and the fine structure to 1%. Ato mic collisions excite antihydrogen atoms to states with n =2; field io nization in a Lorentz-transformed laboratory magnetic field then prepa res a particular n = 2 state, and is used again to analyze that state after it is allowed to oscillate in a region of zero field. This exper iment is feasible at Fermilab.