Physicists Report Evidence of Ultrarare B0 Meson Decay After 40-Year Hunt

The briefing

Phys.org reports that CERN researchers have found evidence for the B0 → μ+μ− decay, in which a meson’s beauty quark annihilates with a down-type quark to produce a muon pair. The observation provides a stringent test of Standard Model predictions first proposed in 1984.