Antimatter Went for a Truck Ride Across CERN and Came Back Intact

The BASE collaboration has driven 92 trapped antiprotons out of CERN's Antimatter Factory by truck and brought them back without losing one. Antiprotons are the antimatter twins of protons, and the Antimatter Factory has been the only place they could be studied at rest.

The reason to move them is magnetic noise. Fields inside the facility fluctuate while it runs, and that fluctuation sets the limit on how precisely the group can compare protons with antiprotons, the team reports in Nature, in a paper published Sept. 16, 2026. Taking antiprotons to a quiet laboratory somewhere else is a strategy the authors expect to allow at least 100-fold better tests of the symmetry between matter and antimatter.

For the journey, the particles sat in BASE-STEP, a transportable Penning trap, which holds charged particles with a magnetic field and a set of voltages.

A crane lifted its frame onto a medium-duty truck, and once the trap was unplugged, batteries and a tank of liquid helium kept it powered and cold. It covered 7.5 kilometers in 24 minutes in ordinary traffic across CERN's Meyrin site, and a reading taken every minute tracked the antiprotons the whole way. The paper reports no particle loss and no measurable change in the trap's vacuum.

Electrons and protons had been moved this way before, in two earlier studies, but whether the extreme vacuum antiprotons need would survive a trip was untested. This batch stayed in the trap for 33 days in all, and the one antiproton that was lost went during voltage ramps used to split the cloud and merge it back, not on the road.

The authors call the transport the starting point for "a new era of antiproton precision measurements." They plan to move antiprotons next into receiver traps at CERN and at Heinrich Heine University in Düsseldorf, Germany.