CERN physicists find evidence of rare particle decay after 42 years
The discovery of an ultra-rare beauty quark decay could help scientists explore the Zeptoverse and test the Standard Model.
Physicists at CERN have identified the first evidence of an extremely rare particle decay following more than four decades of searching, according to Moneycontrol.
The LHCb collaboration detected a process known as 'Bd to mu mu', where a particle containing a beauty quark and a down antiquark decays into two muons. Scientists predict this specific decay happens only once in every 10 billion beauty-particle decays.
The finding reached a statistical significance of 3.2 sigma, which is the first evidence of this decay from a single experiment. The measurement currently aligns with the predictions of the Standard Model.
Researchers used data from 2024 and 2025 alongside observations from 2011 to 2018. They utilised the upgraded Large Hadron Collider beauty (LHCb) detector and machine-learning techniques to distinguish the rare signal from background events.
This discovery may allow scientists to study the Zeptoverse, a scale of nature involving distances as small as a zeptometre. This scale could reveal unknown particles and fundamental forces that have not yet been detected.
While a five-sigma significance is required to claim a formal discovery, scientists intend to collect more data into the early 2030s. A future upgrade could increase the data collection rate by a factor of 10.