Institute of research into the fundamental laws of the Universe

The GBAR Collaboration gathers around 50 members from 17 Institutes, with the goal of measuring the acceleration of hydrogen antiatoms in the Earth gravitational field.  The experiment has been installed at CERN at the AD-ELENA ring.

It produced its first antihydrogen beam in 2022: P. Adrich et al., Eur. Phys. J. C 83, 1004 (2023).

SPP physicists are at the origin of the GBAR project.  Specifically the SPP group has initially developed a novel high-intensity source of positrons, based on an electron linac, managed to store these positrons in a Penning trap, and to produce positronium from their interactions with a porous SiO2 substrate.