CERN Physicists Report First Evidence of Decay Rarer Than One in Ten Billion

GENEVA, SWITZERLAND — Physicists working with the Large Hadron Collider at CERN report evidence of an extraordinarily rare particle decay, one they say could eventually help reveal unknown particles and forces of nature, according to a report in The Debrief.

The process, known as Bd to mu mu, involves a particle containing a "beauty quark" decaying into a pair of muons, the heavier cousins of the electron. Scientists predict it occurs only about once in every 10 billion beauty particles. The search, the report says, has run for more than four decades and was aided by a recently upgraded LHCb experiment.

The result carries a statistical significance of 3.2 sigma, which the team describes as first experimental evidence of the decay. Five sigma is required to declare a discovery, and further observations will be needed. The team also says its measurement agrees with predictions of the Standard Model of particle physics, which is to say the known rules have, for the moment, held.

Hopes for the future are more adventurous. The researchers believe increasingly precise measurements could probe the so-called "Zeptoverse," a hypothetical realm at scales of about one zeptometer, a billionth of a trillionth of a meter. At such distances, physicists hope to find indirect signs of new particles or forces that challenge existing models.

Professor Chris Parkes of the University of Manchester, who led the LHCb collaboration, described the upgrade as a 15-year project involving 1,900 members. Professor Brian Cox, who was not involved, called it "a beautiful example of how science advances," adding that progress may prove incremental or world-changing.