A new path toward gravity experiments with antihydrogen

We propose to use a 13 keV antiproton beam passing through a dense cloud of positronium (Ps) atoms to produce an H¯+ “beam”. These ions can be slowed down and captured by a trap. The process involves two reactions with large cross-sections under the same experimental conditions. These reactions are the interaction of p¯ with Ps to produce H¯ and the e+ capture by H¯ reacting on Ps to produce H¯+. Once decelerated with an electrostatic field and captured in a trap, the H¯+ ions could be cooled and the e+ removed with a laser to perform a measurement of the gravitational acceleration of neutral antimatter in the gravity field of the Earth.