⚡Physicists report first evidence of an ultra-rare particle decay after a 42-year search.

What it means

Physicists at CERN’s Large Hadron Collider — almost certainly the LHCb collaboration — report the first evidence for an ultra-rare decay of a beauty meson, the kind expected in only about one in every 10 billion cases and consistent with the neutral B meson decaying into two muons (B⁰ → μ⁺μ⁻). The result ends a search that has run since the 1980s, and because this decay can only proceed through quantum-loop processes, it is a sensitive test of the Standard Model and a possible window onto new physics.

Accuracy & sourcesGrounded

The claim is solid at the level of a press-release-style announcement: the primary source is a CERN/LHCb result reported by UKRI, the University of Birmingham, Phys.org and The Times, matching the provenance tier of reputable secondary reporting on a named primary source. It is explicitly first evidence, not yet a full 5-sigma observation, so the final discovery status remains open.

How new

Genuinely new: the reporting wave is dated 3 November 2026, and no recirculation year is given.

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