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Originally published September 23, 2011 at 10:01 PM | Page modified September 23, 2011 at 10:37 PM

Physicists explain how neutrino beat Einstein

The day after news broke of a possible revolution in physics — particles moving faster than light, violating Albert Einstein's ultimate speed limit — a scientist leading the European experiment explained it to a standing-room-only crowd.

The Washington Post

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In science, revolutions take time.

And so, the day after news broke of a possible revolution in physics — particles moving faster than light, violating Albert Einstein's ultimate speed limit — a scientist leading the European experiment that made the discovery explained it to a standing-room-only crowd at the European Organization for Nuclear Research, or CERN, the giant particle accelerator outside Geneva, Switzerland, that straddles the Swiss-French border.

The physicist, Dario Auterio, made no sweeping claims.

He and his team did not try to explain what the results might mean for the laws of physics, let alone the broader world. After two hours of technical talk, he said: "Therefore we present to you today this discrepancy, this anomaly."

There's a long history of experimental results that at first seem to contradict relativity, only later to be found to fit neatly with the theory Einstein loved for its simplicity and elegance.

"It's dangerous to lay odds against Einstein," said Rob Plunkett, a physicist at the Fermilab near Chicago who has tried similar speed-of-light experiments and will try to test the new findings.

Harvard University science historian Peter Galison said Einstein's relativity theories have been challenged and "pushed on as hard as any theory in the history of physical sciences ever" and they have survived.

The elegance of Einstein's theory and its proven track record are why physicists greeted the findings with caution and skepticism.

The team Friday explained how it arrived at its results. From 2009 through 2011, the massive OPERA detector buried in a mountain in Gran Sasso, Italy, recorded particles called neutrinos generated at CERN arriving a tad too soon, faster than light can move in a vacuum. If the finding is confirmed, it would throw more than a century of physics into chaos.

Clocking the neutrinos' speed requires knowing two things: the distance of the journey and how long it took. Auterio detailed the extraordinary lengths his team took to make those two measurements. "We spent six months in various cross-checks," he said of the team of 160 physicists from 11 countries collaborating on the OPERA experiment, which is funded by the French and Italian governments.

Starting with GPS measurements and then upgrading the readings by sophisticated means, they measured the distance traveled — 454 miles — to within 8 inches. They factored in the rotation of the Earth, which moves ever so slightly in the flash it takes neutrinos to zoom to the detector. They even stopped traffic in a tunnel running through Gran Sasso mountain to calibrate their instruments.

And when the scientists fired the beam of neutrinos underground from Geneva to Italy, they found it traveled 60 nanoseconds faster than light, 186,282 miles per second.

An audience member asked whether the team accounted for the tugging of the moon on the Earth.

"We took data continuously over three years, so this movement should average out," Auterio said.

His explanations satisfied prominent spectators.

"I want to congratulate you on a beautiful experiment," said Samuel C.C. Ting, the Nobel Prize-winning particle physicist from the Massachusetts Institute of Technology.

About 15,000 viewers tuned into a webcast of the seminar, a huge audience for such a technical talk.

Plunkett, the Fermilab physicist, said: "There's no question this is a result." Translation: The finding holds up to initial scrutiny.

Still, some yet-unknown error could invalidate the results. "This is one of those 'devil in the details' things," Plunkett said.

If neutrinos do travel a smidgen faster than light, it might mean a rewrite, rather than a scrapping, of Einstein's theories, said theoretical physicist Matt Strassler of Rutgers University.

"All the great revolutions in science start with an unexpected discrepancy that wouldn't go away," Strassler said.

Material from The Associated Press is included in this report.

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