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.