Physicists working with CERN’s Large Hadron Collider (LHC) report the detection of evidence of an extraordinarily rare form of particle decay, which they say could help to reveal as-yet unknown particles and other forces of nature.
The discovery comes after more than four decades of searching and was achieved with the help of a recently upgraded LHCb experiment, and incorporates a process known as Bd to mu mu where a particle that contains what physicists call a “beauty quark” decays into a pair of muons—the heavier cousins of electrons.
“The upgraded LHCb was a major undertaking,” said Professor Chris Parkes, head of the Department of Physics and Astronomy at The University of Manchester.
Parkes, who led the international LHCb collaboration, called the effort “a 15-year design and construction project from a 1,900-member international collaboration.”
A Rare Form of Particle Decay
Scientists currently predict that the rare form of decay observed during the recent experiment occurs just once in about every 10 billion beauty particles. Because of this, such conditions are exceedingly difficult to detect, even using some of the most sensitive equipment currently accessible to physicists.
To overcome this challenge, researchers at the University of Manchester helped develop advanced detector technology that made the measurement possible, which included a precision silicon detector that allowed them to track particles generated during very high-energy collisions.
During experiments, the research team achieved results with a statistical significance of 3.2 sigma, which offered the first experimental evidence of the decay. Still, additional observations will be needed to meet the required five-sigma threshold required to declare a discovery.
Significantly, the team says their measurement agrees with predictions that align with the Standard Model of particle physics.
Into the “Zeptoverse”
In the future, the researchers believe that increasingly precise observations will eventually become available, which could help scientists probe what physicists dub the “Zeptoverse,” a hypothetical realm consisting of distances as tiny as just one zeptometer—that is, around a billionth of a trillionth of a meter.
At such remarkably short scales, physicists hope that indirect evidence of new particles may be uncovered, or even signs of forces that may challenge some of our existing models of the universe and how it works.
“This is an important result and a beautiful example of how science advances,” said Professor Brian Cox, particle physicist at the University of Manchester.
Cox, who was not involved in the recent CERN experiment, said that over time, equipment upgrades like those that enabled the recent work occur over time, allowing researchers like him and his colleagues to see the world around us in far greater detail.
“Occasionally we see something we don’t understand, and then progress is made,” Cox said.
“We cannot know whether this progress will be incremental or genuinely world-changing—that’s science!” he added, calling the recent LHCb experiment “a major scientific success.”
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.