Proton’s magnetic properties pinned down
Precise measurement could help reveal subtle differences between matter and antimatter
A lone proton’s magnetism is pretty weak, yet it’s reeling in researchers trying to solve one of the biggest mysteries in physics.
A new measurement quantifies the feeble intrinsic magnetism of the proton and sets the stage for a similar test of the proton’s antimatter counterpart. By comparing this magnetic property of protons with that of antiprotons, researchers hope to gain insight into why the universe is dominated by matter rather than antimatter.
Scientists have a pretty good handle on the proton, but in recent years they have used increasingly sophisticated equipment to probe the particle’s basic properties with unprecedented precision. One such property is the magnetic moment, which describes how a particle responds to a magnetic field. “Each fundamental particle behaves like a very tiny bar magnet or compass needle,” explains Stefan Ulmer, a particle physicist at RIKEN in Wako, Japan.
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