Mobile trap transports 92 antiprotons by road and stores them for over a month in world first

An antiproton is the antimatter counterpart of a proton. It has the same mass as a proton but the opposite electric charge and other reversed properties. A particle trap is a device that confines charged particles in empty space. This matters because antiprotons are destroyed when they meet ordinary matter, including the trap’s walls.

The BASE team uses a Penning trap. Electric fields confine the antiprotons along the device’s length. A strong magnetic field keeps their sideways motion contained. Together, these fields make the particles move in controlled paths without touching the container. The trap can therefore carry and store them like an invisible package.

This technology made the reported road journey possible. In March 2026, BASE transported antiprotons in a purpose-built trap loaded on a truck. Such traps let scientists perform precise antimatter studies away from CERN. They also make future transfers between specialized laboratories more realistic, provided the fields, vacuum, power, and vibration controls remain reliable.

The reported experiment transported 92 antiprotons by road over about 1,200 kilometres. The journey connected CERN in Geneva with Heinrich Heine University Düsseldorf. The particles were not packed in a container like ordinary material. They were held inside a purpose-built electromagnetic trap mounted on a truck.

The trap preserved the antiprotons during transport and later storage. Electric fields confined their motion along the trap, while magnetic fields controlled their sideways movement. The stored particles remained available for approximately 100 days. This duration showed that the system could preserve a useful sample well beyond the trip itself.

These numbers matter because antimatter experiments normally operate beside the production facility. A successful long-distance journey changes that practical limit. It suggests that future experiments could receive antiprotons at other laboratories, where different instruments or quieter environments may improve measurements. The result, presented by BASE in Nature, is a transport milestone rather than routine delivery service.

The experiment was considered a world first because antiprotons had never before been transported by road inside a purpose-built particle trap. Producing antimatter is difficult, but moving it adds vibration, electrical, vacuum, and safety challenges. The particles must stay confined while the vehicle travels through changing conditions.

BASE solved this problem by placing the antiprotons in a portable electromagnetic trap. The trap’s electric and magnetic fields held the charged particles in empty space. A truck carried the apparatus from CERN in Geneva to Düsseldorf. The particles then remained stored for about 100 days, showing that transport did not immediately destroy the sample.

The achievement matters beyond its headline. CERN remains the place where the antiprotons were produced, but they need not remain there for every experiment. Reliable transport could connect CERN’s antimatter supply with laboratories possessing specialized equipment. The Nature report documents this first demonstration and the practical lessons needed to make such transfers safer and more dependable.

CERN is where BASE produces and captures antiprotons, but production and measurement are different tasks. Other laboratories may offer equipment, working conditions, or scientific expertise that CERN cannot provide for every experiment. Moving the particles lets researchers bring CERN’s antimatter supply to those facilities instead of rebuilding every capability at one site.

The road experiment demonstrated this idea directly. BASE placed captured antiprotons in a purpose-built trap and carried them from CERN in Geneva to Heinrich Heine University Düsseldorf. The trap maintained confinement during the journey and supported storage afterward. The particles therefore became a transportable research sample rather than material tied permanently to the production facility.

This flexibility could broaden antimatter research. Scientists might compare measurements made in different laboratories or use instruments designed for particular precision tests. The current demonstration does not make transport simple: the system needs reliable fields, power, vacuum, and vibration control. However, the Nature report shows that distance no longer automatically prevents collaboration with CERN’s antiproton source.

An antiproton cannot safely touch ordinary matter. On meeting a proton, it annihilates with it, converting their mass into other particles and energy. Contact with residual gas or a trap wall can therefore remove an antiproton from the experiment. Losing even a small sample matters because antiprotons are difficult to produce and capture.

This is why the particles travel inside a high-vacuum electromagnetic trap rather than a normal box. Electric fields keep them confined in one direction, and magnetic fields restrain their radial motion. The antiprotons remain suspended away from the walls. During transport, the apparatus must also maintain power, field stability, vacuum quality, and resistance to vibration.

The BASE demonstration showed that these conditions can be preserved on a truck. The collaboration transported 92 antiprotons about 1,200 kilometres and stored them for approximately 100 days. The result does not remove the danger of annihilation, but it proves that careful engineering can manage it during a long journey.

Antiprotons carry electric charge, so electromagnetic fields can control their motion without touching them. In a Penning trap, shaped electric fields provide confinement along the device’s length. They act like an invisible barrier that stops the particles from escaping through either end.

A magnetic field handles the sideways direction. A moving charged antiproton spirals around magnetic field lines instead of flying directly toward the wall. The electric and magnetic fields work together: one controls axial motion, while the other restricts radial motion. The particles remain suspended in a high vacuum and can be measured or transported.

This mechanism made BASE’s road experiment possible. The trap was purpose-built to keep antiprotons confined despite movement from a truck. The successful transport from CERN to Düsseldorf, followed by approximately 100 days of storage, shows that electromagnetic confinement can survive real-world handling. It also illustrates why a trap is more than a container: it is an active system that continuously controls particle motion.

Antimatter consists of particles related to ordinary matter particles but with opposite electric charge and other reversed quantum properties. An antiproton corresponds to a proton, while a positron corresponds to an electron. Matter and antimatter can both exist, but when corresponding particles meet, they annihilate and release energy.

This relationship gives scientists a powerful test of fundamental physics. The early universe should have produced matter and antimatter in closely related amounts under simple expectations. Yet the universe we observe is dominated by matter. Comparing antiprotons with protons can reveal whether tiny differences help explain that imbalance.

BASE’s work contributes to this effort by making antiprotons controllable and measurable. Its March 2026 experiment transported 92 antiprotons from CERN toward Düsseldorf and stored them for about 100 days. Moving antimatter to other facilities could enable new precision tests. The road journey does not solve the cosmic imbalance, but it expands the places and conditions in which scientists can investigate it.