Two experiments at the recently-restarted Large Hadron Collider have been combined to reveal a never before seen subatomic process.
Researchers with the CMS and LHCb collaborations observed the decay of the Bs particle into two muons for the first time, the Fermi National Accelerator Laboratory reported. The Bs particle is a heavy composite particle made up of a bottom antiquark and a strange quark. In the past, the decay had been predicted to occur about four times out of a billion, and now the extremely rare phenomenon has been observed.
"It's amazing that this theoretical prediction is so accurate and even more amazing that we can actually observe it at all," said Syracuse University Professor Sheldon Stone, a member of the LHCb collaboration. "This is a great triumph for the LHC and both experiments."
The researchers made their discovery when searching for holes in the Standard Model, which workd to explain the behavior of all known observable matter. This model is known to be incomplete because it does not take dark matter or the abundance of antimatter present in our universe into account.
"Many theories that propose to extend the Standard Model also predict an increase in this Bs decay rate," said Fermilab's Joel Butler of the CMS experiment. "This new result allows us to discount or severely limit the parameters of most of these theories. Any viable theory must predict a change small enough to be accommodated by the remaining uncertainty."
The team is looking at particles that contain bottom quarks because they are easily detectable, long lived, and relatively abundant.
"We also know that Bs mesons oscillate between their matter and their antimatter counterparts, a process first discovered at Fermilab in 2006," Stone said. "Studying the properties of B mesons will help us understand the imbalance of matter and antimatter in the universe."
This phenomenon is mysterious because the equal amounts of matter and antimatter believed to have been produced by the Big Bang should have destroyed each other on contact, but have somehow continued to exist.
"The LHC will soon begin a new run at higher energy and intensity," Butler said. "The precision with which this decay is measured will improve, further limiting the viable Standard Model extensions. And of course, we always hope to see the new physics directly in the form of new particles or forces."
The findings were published in a recent edition of the journal Nature.
