# After 40 years of searching, physicists find evidence for an ultrarare particle decay

- Source: Phys.org - latest science and technology news stories
- Published: 2026-11-05T17:30:02+00:00
- Category: Science
- Original: https://phys.org/news/2026-11-years-physicists-evidence-ultrarare-particle.html
- Canonical: https://groundlevelnews.com/story/after-40-years-of-searching-physicists-find-evidence-for-an-ultrarare--7945b7/

Physicists at CERN report that they've detected evidence of a rare meson particle decay (B⁰→ µ⁺µ⁻) that occurs when the meson's beauty quark annihilates with a down-type quark. The pair decays into a muon and antimuon, which are particles similar to electrons. Because evidence for this decay helps test theoretical predictions from the Standard Model, physicists have been waiting for it since 1984,

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