Physicists unveil results helping explain universe

[Buster's Uncle]

Physicists unveil results helping explain universe
Associated Press
JOHN HEILPRIN 1 hour ago

FILE - In this Aug. 7, 2010 file picture an amateur photographer takes a picture in the assembly room of the elements of the LHC (large hadron collider) during the Particle Physics Photowalk at the European Particle Physics laboratory (CERN) in Geneva, Switzerland. Two scientific teams have for the first time precisely recorded an extremely rare event in physics that adds certainty to how we think the universe began, leaders at the world's top particle physics lab said Friday July 19, 2013. Two of the teams at the European Center for Nuclear Research, or CERN, say they measured a particle called "Bs" decaying into a pair of muons, a fundamental particle. The results are being formally unveiled at a major physics conference in Stockholm later Friday. (AP Photo/Keystone/Salvatore Di Nolfi)

GENEVA (AP) — After a quarter-century of searching, scientists have nailed down how one particularly rare subatomic particle decays into something else — a discovery that adds certainty to our thinking about how the universe began and keeps running.

The world's top particle physics lab said Friday it had measured the decay time of a particle known as a Bs (B sub s) meson into two other fundamental particles called muons, which are much heavier than but similar to electrons. It was observed as part of the reams of data coming from CERN's $10 billion Large Hadron Collider, the world's largest atom smasher, on the Swiss-French border near Geneva.

The rare sighting at the European Center for Nuclear Research, known by its French acronym CERN, shows that the so-called standard model of particle physics is "coming through with flying colors," though it describes only 5 percent of the universe, said Pierluigi Campana, who leads one of the two main teams at CERN involved in the research.

Campana called the results an important development that helps confirm the standard model, a theory developed over the past half-century to explain the basic building blocks of matter.

It applies to everything from galaxies and stars to the smallest microcosms, showing how they are thought to have come into being and continue to function. The results were formally unveiled at a major physics conference in Stockholm.

FILE - In this March 30, 2010 file picture the globe of the European Organization for Nuclear Research CERN, is illuminated outside Genva, Switzerland.

Researchers have been looking for this particular rare decay for a long time.

"This is a process that particle physicists have been trying to find for 25 years," said Joe Incandela, leader of the second team involved in the research. He called it a "rare process involving a particle with a mass that is roughly 1,000 times smaller than the masses of the heaviest particles we are searching for now."

The standard model also predicted a new subatomic particle discovered last summer. The long-sought Higgs boson creates what scientists call a "sticky" energy field that acts as a drag on other particles and gives them mass, without which particles wouldn't hold together — and there would be no matter.

The newest research shows that only a few Bs particles per billion decay into pairs of muons, which was along the lines of what was predicted under the standard model. But because the Bs particle's decay helps confirm an old theory, some scientists also expressed a bit of disappointment they had not found something completely unexpected or new.

"This is a victory for the standard model," said Joel Butler of the United States' Fermi National Accelerator Laboratory, near Chicago. "But we know the standard model is incomplete, so we keep trying to find things that disagree with it."

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