LHCb team led by Cambridge finds first evidence of rare beauty quark decay into two muons

A team led by physicists from the University of Cambridge has obtained the first evidence of an extremely rare decay of the beauty quark, a process searched for since 1984, according to Infobae. The result was announced on November 3 at CERN near Geneva, where the Large Hadron Collider (LHC) operates. The work was done at the LHCb experiment, and the results have not yet passed peer review; publication in a scientific journal is expected. infobae.comInfobaeinfobae.comOpen source ↗

What was measured

Beauty quarks are not stable in nature, but they are produced in large numbers in high-energy LHC collisions. The rarest of their decays occurs when a beauty quark and an antiparticle of opposite charge annihilate each other and produce two muons, heavier variants of the electron. The process is so restricted by the laws of physics that it happens in about one in ten billion beauty quarks. infobae.comInfobaeinfobae.comOpen source ↗

The researchers state that this is the first time evidence for this rare decay has been obtained from a single experiment. The team combined data collected from 2011 to 2018 with a new, large sample from 2024 and 2025, made possible by a major upgrade of LHCb completed in 2024. The signal reached 3.2 sigma, above the three-sigma threshold accepted as statistical evidence of a new phenomenon. infobae.comInfobaeinfobae.comOpen source ↗

Why the decay matters for the zetaverse

The Standard Model describes all known particles and forces, but it leaves open the asymmetry between matter and antimatter and the nature of the energy driving the expansion of the universe. The frequency of this decay is sensitive to particles that are not in the model. If only known particles exist, the rate follows Standard Model predictions; entities at still smaller distances would offer an alternative path and change that rate in a detectable way. The authors call that range of scales the zetaverse. The current results show no deviation from the prediction, but the precision of the technique can reveal differences in future data. infobae.comInfobaeinfobae.comOpen source ↗

The main technical difficulty was background noise: the sought signals were buried under a large volume of irrelevant data. To separate them, the team of about 20 physicists from the United Kingdom, Germany, Italy, Spain and the Netherlands used pattern-recognition techniques for large datasets. Harry Cliff of the Cavendish Laboratory, who led the analysis, said: "We are knocking on the door of the zetaverse now." Tim Gershon of the University of Warwick, responsible for LHCb, said the result shows the experiment's capabilities for probing nature at a fundamental level. infobae.comInfobaeinfobae.comOpen source ↗