Proton transport from the antimatter factory of CERN.

Precision measurements using low-energy antiprotons, exclusively available at the antimatter factory (AMF) of CERN, offer stringent tests of charge-parity-time (CPT) invariance, which is a fundamental symmetry in the Standard Model of particle physics. These tests have been realized, for example, in antiprotonic helium and antihydrogen. In our cryogenic Penning-trap experiments, we measure the magnetic moments and charge-to-mass ratios of protons and antiprotons and now provide the most precise test of CPT invariance in the baryon sector. Our experiments are limited by magnetic field fluctuations imposed by the decelerators in the AMF; therefore, we are advancing the relocation of antiprotons to dedicated precision laboratories. Here we present the successful transport of a trapped proton cloud from the AMF using BASE-STEP-a transportable, superconducting, autonomous and open Penning-trap system that can distribute antiprotons into other experiments. We transferred the trapped protons from our experimental area at the AMF onto a truck and transported them across the Meyrin site of CERN, demonstrating autonomous operation without external power for 4 h and loss-free proton relocation. We thereby confirm the feasibility of transferring particles into low-noise laboratories in the vicinity of the AMF and of using a power generator on the truck to reach laboratories throughout Europe. This marks the potential start of a new era in precision antimatter research, enabling low-noise measurements of antiprotons, the charged antimatter ions and (ref. ), and other accelerator-produced ions, such as hydrogen-like lead or uranium ions.