https://doi.org/10.1140/epjc/s10052-014-2731-8
Regular Article - Theoretical Physics
Shaping the distribution of vertical velocities of antihydrogen in GBAR
1
Laboratoire Kastler-Brossel, CNRS, ENS, UPMC, Campus Jussieu, 75252, Paris, France
2
Institut de Recherche sur les lois Fondamentales de l’Univers, CEA-Saclay, 91191, Gif-sur-Yvette, France
3
Institut Max von Laue-Paul Langevin, 6 rue Jules Horowitz, 38042, Grenoble, France
4
P.N. Lebedev Physical Institute, 53 Leninsky prospect, 117924, Moscow, Russia
* e-mail: gabriel.dufour@upmc.fr
Received:
4
November
2013
Accepted:
20
December
2013
Published online:
30
January
2014
GBAR is a project aiming at measuring the free-fall acceleration of gravity for antimatter, namely antihydrogen atoms (
). The precision of this timing experiment depends crucially on the dispersion of initial vertical velocities of the atoms as well as on the reliable control of their distribution. We propose to use a new method for shaping the distribution of the vertical velocities of , which improves these factors simultaneously. The method is based on quantum reflection of elastically and specularly bouncing with small initial vertical velocity on a bottom mirror disk, and absorption of atoms with large initial vertical velocities on a top rough disk. We estimate statistical and systematic uncertainties, and we show that the accuracy for measuring the free fall acceleration 
of could be pushed below 
under realistic experimental conditions.
© The Author(s), 2014
