Science & Tech · Science & Environment · 10 hrs ago
Physicists trap a single positron for months
Physicists at Northwestern University trapped a single positron for months in a laboratory in the United States.
A positron is the antimatter counterpart of an electron, with the same mass but the opposite electric charge.
Because positrons annihilate when they meet electrons, researchers slowed them using a tungsten crystal and kept one in a vacuum with electromagnetic fields.
The trap let the team study the positron’s quantum states, which are difficult to observe when the particle quickly disappears.
The researchers now plan to measure its magnetic moment and compare it with the electron’s.
The Standard Model predicts their magnetic moments should match, but a difference could point to physics the model does not explain.
That could help researchers investigate why the universe contains matter rather than equal amounts of matter and antimatter.
Physicists at Northwestern University trapped a single positron for months, allowing them to study its quantum states.
The positron was slowed using a tungsten crystal and confined in a vacuum trap with electromagnetic fields.
The researchers plan to measure the positron’s magnetic moment and compare it with the electron’s.
The Standard Model predicts that the two particles’ magnetic moments should be identical.
A difference could offer clues to why the universe contains more matter than antimatter.
Reports describe the trapping period as months, while Scientific American says the positron was studied for a month.
- Who
- Physicists at Northwestern University, led by Gerald Gabrielse.
- What
- They trapped a single positron and studied its quantum states.
- When
- The achievement was reported on October 21, 2026.
- Where
- Northwestern University’s laboratory in Illinois, United States.
- Why
- To enable precise measurements of the positron’s magnetic moment and compare it with the electron’s.
This story does not have two clearly opposing sides.
Positrons from a radioactive sodium source were slowed by passing through a tungsten crystal.
Electromagnetic fields confined a single positron in a vacuum trap.
Researchers used controlled microwave bursts to move the positron into a higher energy state.
The team’s achievement was reported in Physical Review Letters.
- Particle
- Positron, the antimatter counterpart of the electron
- Research institution
- Northwestern University
- Slowing material
- Tungsten crystal
- Source isotope
- Sodium-22
- Electron magnetic-moment precision
- 1 part in 10 trillion
4 sources
What people are saying
The standard model seems to be inconsistent, or at least significantly incomplete, with basic features of the universe, like why we have a universe at all.
If you want to hold on to antimatter, you have to hold it in a container without walls.
This has the potential to become one of the most precise measurements of a fundamental constant in physics.