Science

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

Source: Phys.org · Published 5 Nov 2026, 17:30

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…

Key points

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…

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

Key points

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