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Physicists trap a single particle of antimatter for months, setting up a sharp test of physics' best theory
In brief
Physicists at Northwestern University near Chicago have trapped a single positron, the antimatter counterpart of the electron, and cooled it to its lowest possible energy state, keeping it suspended for months without touching any ordinary matter. The study, led by Gerald Gabrielse and published on October 21, 2026 in Physical Review Letters, sets up one of the most precise comparisons ever between matter and antimatter.
A container with no walls
When a positron meets an electron, the two annihilate in a burst of energy, so a positron cannot be kept in an ordinary box. The team instead used a trap made of carefully shaped electric and magnetic fields that holds the particle in empty space in a near-perfect vacuum. They caught a fast positron released by radioactive sodium-22, slowed it down and cooled it to about 0.3 degrees above absolute zero. The researchers call the result a "one-positron quantum cyclotron": the particle behaves like an artificial atom whose quantum energy levels they can nudge with tuned microwaves and read out. Gabrielse stressed that the experiment is not dangerous, saying there is not enough antimatter to make an explosion.
Why it matters
The Standard Model of particle physics says electrons and positrons should be near-perfect mirror images. Yet it cannot explain why the universe is made almost entirely of matter, when the Big Bang should have created equal amounts of both. Gabrielse's group previously measured the electron's magnetic moment to about one part in 10 trillion. Now they plan to measure the positron the same way and compare the two. Gabrielse said that if the results differ, it "would be the biggest discovery in physics in the last century". Nature's news team quoted CERN antimatter physicist Barbara Maria Latacz calling it a "remarkable achievement". The work was supported by the U.S. National Science Foundation.
VSH take: it is a lovely reminder that some of the biggest questions in science are tested with a single, patient particle. Students can practise the huge and tiny numbers involved with our scientific calculator, convert temperatures with the unit converter, and explore more space science on our Live Earth from space page. This week we also covered NASA's new way of choosing science missions.
This is our own summary of Northwestern University's announcement and Nature's news coverage. ViralScopeHub is not affiliated with Northwestern University or Nature.
Why it matters
Comparing a positron with an electron to extreme precision is one of the cleanest ways to look for cracks in the Standard Model and to understand why matter won out over antimatter.
People also ask
What is a positron?
The antimatter counterpart of the electron. It has the same mass but the opposite electric charge, and it annihilates when it meets an electron.
How did the team keep it from touching anything?
They used a trap of electric and magnetic fields that suspends the positron in a near-perfect vacuum, cooled to about 0.3 degrees above absolute zero.
What comes next?
Measuring the positron's magnetic moment with extreme precision and comparing it with the electron's, which the same group has measured to about one part in 10 trillion.
Related free tools: Scientific Calculator, Unit Converter
Sources
- Northwestern University: Scientists trap and tame a single particle of antimatter for months
- Nature: A single antimatter particle in a cage opens door to 'revolutionary' physics
Every ViralScopeHub news item is an original summary written in our own words. We link to the original reporting so you can read the full story from the publisher.
