Antimatter Gravity Measurements with Cold Antihydrogen: the AEgIS Experiment

The AEgIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) experiment has the objective of testing the weak equivalence principle for antimatter, by studying the free fall of antihydrogen atoms in the Earth’s gravitational field, as well as carrying out a measurement of the hyperfine splitting of their ground state. A pulsed cold beam of antihydrogen produced by charge exchange between cold positronium (laser excited into a Rydberg state with principal quantum number n ∼ 25-35) and cold antiprotons will be transformed into a horizontal beam through Stark acceleration, whose free fall will be measured by a classical moirée deflectometer. The status of different crucial steps towards this goal is presented.