Overview
- LHCb, in a Cambridge‑led analysis, combined data from 2011–2018 and new 2024–2025 runs to produce a 3.2σ signal for the B0 (Bd) → μ+μ− decay reported on Tuesday.
- The decay is extraordinarily rare—about one event in ten billion B‑meson decays—and this is the first time a single experiment has reached roughly three‑sigma evidence for it.
- The 2024 LHCb detector upgrade and machine‑learning analysis were essential to suppress background and extract the tiny signal from a much larger data sample.
- The measured rate agrees with Standard Model predictions so far but the result is unpeer‑reviewed and will need more data and scrutiny to test for contributions from new particles.
- Teams say mid‑2030s upgrades to LHCb and future colliders will be needed for precision tests and that UK funding shifts may affect Britain’s long‑term role in the programme and in training engineers and scientists.