Misbehaving kaons could hint at the existence of new particles
Certain extremely rare decays seem to be happening more often than expected
A little-known type of particle called a kaon may be stepping into the spotlight.
The exotic subatomic particles are attracting attention for their unexpected behavior in an experiment at a Japanese particle accelerator. Rare kaon decays seem to be happening more frequently than expected, according to the KOTO experiment. If the result holds up to further scrutiny, it could hint at never-before-seen particles that would dethrone particle physicists’ reigning theory, the standard model.
There’s still a good chance KOTO’s result will be overturned, says Yuval Grossman of Cornell University. But “there’s the extremely exciting possibility that they see something totally new.”
The standard model describes the particles and forces that underpin the universe. But there are still puzzles to solve, such as why there’s more matter than antimatter in the universe (SN: 11/25/19). So physicists are leaving no stone — or kaon — unturned in efforts to test the theory. One realm subject to scrutiny is very rare decays of kaons. The standard model predicts precisely how rare those decays are, and KOTO, based at the Japan Proton Accelerator Research Complex in Tokai, was built to test that prediction.