Sounds almost too Hollywood to be true, but Science News is covering some unexpected findings from a Japanese particle accelerator, where researchers say chaotic little particles called “kaons” might force physicists to rewrite the standard model that describes how the bits and pieces that make the universe fit together:
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.
KOTO is searching for a particular decay of a kaon into three other particles. One of those particles, a pion, produces light that KOTO detects. The other two, a neutrino and an antineutrino, sail through the detector without a blip. That means KOTO is looking for a specific signature: one pion and nothing else. One possible explanation for the four decays is that the kaon might be decaying into a pion plus a new type of particle that, like neutrinos, leaves no trace. That scenario would reproduce the one-pion signature KOTO is searching for, and might happen more often, explaining the extra decays.
But there’s a catch. KOTO studies kaons that have no electric charge, but other experiments studying charged kaons see no anomaly. That discrepancy is difficult to explain: If the new particle really existed, it should show up for both types of kaons.
Still, there are ways around this problem, physicist Teppei Kitahara and colleagues report in a paper accepted in Physical Review Letters. For example, the differing sizes of kaon experiments could be part of the answer. At just a few meters long, “KOTO is very small” compared with other kaon experiments, says Kitahara, of Nagoya University in Japan. “This means unstable new particles can easily escape the detector.”
Scientists are also considering potential connections to other physics puzzles. For example, experimental measurements disagree with predictions for the magnetic properties of electron-like particles called muons. “If you want to explain this … you need a model beyond the standard model,” says physicist Xiaoping Wang of Argonne National Laboratory in Lemont, Ill. She and colleagues have come up with a hypothetical particle that could simultaneously explain the muon conundrum and the unexpected kaon decays, the team reports January 17 at arXiv.org.
You can read Kitihara’s paper on the experiment here.