LHCb finds single-experiment evidence of a decay predicted once per 10 billion beauty-particle decays

LHCb has found the first evidence from a single experiment of a Bd particle decaying into two muons, a process predicted to occur about once per 10 billion beauty-particle decays. Combining data from 2011–18 and 2024–25 brought the signal to 3.2 sigma, short of the five-sigma discovery threshold. The result agrees with theory; more precise measurements could reveal signs of new particles.