Science
Particle physics
LHCb sees 3.2-sigma evidence that a neutral B meson decays to two muons, matching the Standard Model so far
The LHCb collaboration at CERN reports what UKRI calls the first evidence for the decay of a neutral B meson into two muons, a process the Standard Model puts at roughly one in ten billion decays. Combined with earlier data the significance is 3.2 sigma, short of the 5 sigma discovery bar. The new data are 18 inverse femtobarns of 13.6 TeV collisions from 2024 and 2025. Every measurement agrees with Standard Model predictions.