The fractional resolution achieved in our precision tests of matter–antimatter symmetry – comparing the fundamental properties of antiprotons and protons – is improving rapidly. The most precise test of CPT invariance in the baryon sector, conducted in our trap system, has achieved a fractional resolution of 16 parts per trillion, with clear potential to improve by at least one to two orders of magnitude. However, accelerator operations at CERN introduce fluctuations that ultimately limit the achievable measurement precision within the facility.
To overcome this limitation, we made the strategic decision in 2018, enabled by reservoir, extraction, and non-destructive detection techniques developed within BASE, to construct a transportable antiproton trap. This system allows antiprotons to be moved out of the accelerator environment into dedicated offline laboratory space and injected into dedicated high-precision experiments. After years of conceptual design, development, testing, and commissioning, we have now demonstrated the first successful transport of antiprotons on a truck. This achievement marks a crucial milestone in the BASE experimental program and represents a potentially transformative step towards extending CERN’s antimatter research into precision laboratories beyond the accelerator complex.
The open, autonomous, cryogenic Penning-trap system developed for this purpose – BASE-STEP – was constructed under the leadership of BASE deputy spokesperson Christian Smorra, with support from the ERC Starting Grant STEP. High-precision offline laboratories are currently being constructed at the BASE-related Institute for Quantum Technologies and Fundamental Symmetries at Heinrich Heine University Düsseldorf, Germany.