Antihydrogen studies aim to shed light on the observed
baryon/antibaryon asymmetry in the Universe by comparing the properties
of matter and antimatter with very high precision. In the context of the
GBAR experiment  located at CERN, our aim is to perform a measurement
of the antihydrogen Lamb shift with an uncertainty of 100 ppm, which
allows extracting the antiproton charge radius at a level of 10% .
Due to the two years shutdown of the accelerator complex at CERN, no
experiments with antihydrogen can be performed until 2021. In the
meantime, the setup is being tested and optimized by using the same
detection method with a hydrogen beam at ETH Zurich. The experimental
setup and the current status will be presented.
 P. Pérez et al., “The GBAR antimatter gravity experiment,” Hyperfine
Interactions 233, 21–27 (2015)
 P. Crivelli et al., "Antiproton charge radius", Phys.Rev. D94 (2016)
no.5, 052008 (2016)