🇮🇳 Trending in India · 23 October 2026
What is antimatter, and how did scientists trap one particle for a month?
What is antimatter?
Every normal particle of matter has an antimatter partner with the same mass but the opposite charge. The antimatter partner of the electron is called the positron (or anti-electron). When matter and antimatter meet, the two destroy each other, which scientists call annihilation. That is why antimatter is very hard to store and study.
How antimatter was discovered
British physicist Paul Dirac predicted the anti-electron in his theory, describing a particle with the same mass as an electron but the opposite charge. In 1932, American physicist Carl Anderson saw its track in a cloud chamber photograph of cosmic rays at the California Institute of Technology in Pasadena. This was the first experimental proof that antimatter exists, and Anderson won the 1936 Nobel Prize in Physics for discovering the positron.
The new experiment
The Northwestern team got positrons from sodium-22, a radioactive isotope that gives off positrons when it decays. They slowed one positron down and held it in a Penning trap, a device that uses electric and magnetic fields to keep a particle in the middle of an empty vacuum. The trap was cooled to about 0.3 degrees above absolute zero. Gabrielse explained that you cannot hold antimatter in an ordinary container, so you need 'a container without walls'.
A 'one-positron quantum cyclotron'
The team calls its device a one-positron quantum cyclotron. They cooled the positron to its lowest energy level, called the quantum ground state. Then they used tuned microwaves to push it up one energy level at a time and to flip its spin. They kept the single positron for months, and the researchers say it could be held for as long as they want.
Why it matters
The team plans to measure the positron's magnetic moment, which is the strength of its tiny magnetic field, much more precisely than before. The electron's magnetic moment has already been measured to 1 part in 10 trillion. If physics treats matter and antimatter the same way, as a rule called CPT symmetry says it should, the two values should match exactly. Any difference would point to physics beyond the Standard Model, and studies like this could help explain why the universe is made mostly of matter.
Quick points
Quick quiz
1. Who discovered the positron, the first known antimatter particle, in 1932?
2. The positron is the antimatter counterpart of which particle?
3. Which device did the Northwestern University team use to hold a single positron for months?
Sources
- Physicists trap a single antimatter particle for a month (Scientific American)
- A Quantum Cyclotron for Antimatter (Physics, APS)
- Physicists Hold Single Antimatter Particle for Months (Sci.News)
- One-positron quantum cyclotron could put the Standard Model to the test (Physics World)
- Carl Anderson – Biography (Famous Scientists)
