On a single day in March 2026, a truck rumbled around the grounds of CERN, the giant physics laboratory near Geneva, carrying something no vehicle had ever moved before: 92 pieces of antimatter. Scientists drove those antiprotons for half an hour and roughly 8 kilometers (5 miles), then unloaded the trap that held them — and not one particle was lost.
This was the first time antiprotons had ever been transported by road, and it happened thanks to the BASE collaboration, led by Professor Dr Stefan Ulmer and Dr Christian Smorra of Heinrich Heine University Düsseldorf (HHU). Their findings now appear in the journal Nature.
Keeping safe enough to move matters more than you might think. Antiprotons are the antimatter twins of protons, the positively charged pieces inside an atom's nucleus. When matter and antimatter meet, they destroy each other in a flash of energy, so you cannot just drop these particles into any old box. You need a special device called a Penning trap, which uses electric and magnetic fields to hold charged particles in an ultra-high vacuum.
But the trap in the CERN "Antimatter Factory" — the only facility on Earth that can produce, store, and study low-energy antiprotons — has a frustrating limit. Dr Smorra explained that the facility's own machinery causes small wobbles in the magnetic field, which blur their measurements. "We can only find better conditions outside CERN," he said. Their goal: to move the antiprotons to a quieter, high-precision laboratory elsewhere and boost their measurement accuracy by at least 100 times.
Comparing protons and antiprotons is one of the best ways to hunt for differences between matter and antimatter. In recent years, Professor Ulmer's team has already measured the magnetic properties of both particles with astonishing precision — down to fractions of a part per billion. So far, the two have matched perfectly. But better measurements could one day reveal a tiny difference that helps explain why the universe is made of matter at all.
Marcel Leonhardt, a doctoral researcher at HHU and the study's lead author, and his team stored the 92 antiprotons for more than a month, watching them the whole time. During a test, just one antiproton was lost when it annihilated. The team also achieved a vacuum of better than 2.2 × 10⁻¹⁸ mbar — far better than their own design goal — to keep the particles from colliding with stray gas.
Next stop on the open road: a trip toward Düsseldorf, where the antiprotons could eventually help unlock the deepest secret of why anything exists at all.