The Trouble With Neutrinos That Outpaced Einstein’s Theory

The British astrophysicist Arthur S. Eddington once wrote, “No experiment should be believed until it has been confirmed by theory.”

So when a group of physicists going by the acronym Opera announced in September that a batch of the strange subatomic particles known as neutrinos had traveled faster than the speed of light in a 457-mile trip through the earth, the first response among many physicists was to wonder what had gone wrong with the experiment. 

After all, Albert Einstein’s theory of relativity, which proclaimed the speed of light as the cosmic speed limit, is the foundation of modern science and has been shown to work to exquisite precision zillions of times. 

Knock it down and you potentially open the door to all kinds of things, like the ability to go back in time and kill your grandfather.

That, of course, did not stop the rest of us in the physics bleachers from dragging the old guru of space-time by his frizzy coronal hair into the media version of the public square and crowing that, perhaps this time at last, Einstein was finally going to be proved wrong. 

Neutrino jokes proliferated on the Internet, as well as this rousing song by the Corrigan Brothers and Pete Creighton: 

Tooraloo, tooraloo, tooraloo, tooralino,

Is light now slower than a neutrino?

Now it seems that Einstein’s six-month nightmare may be over.

Last week another team of physicists whose apparatus lives right next door to the Opera group — under Gran Sasso mountain in Italy — reported that they had clocked neutrinos, produced in an accelerator at CERN, outside Geneva, racing over the same path to Gran Sasso at the speed of light and not a whit faster. 

Which is exactly how fast scientists had always thought the enigmatic particles, with barely zilch for mass, should go.

The second group, which goes by the acronym Icarus, was led by Carlo Rubbia, a former director of CERN and a Nobel-winning physicist, who called the results “very convincing.”

Physicists swung into line with great sighs of relief.

“The evidence is beginning to point toward the Opera result being an artifact of the measurement,” said CERN’s research director, Sergio Bertolucci.

Cue the famous picture of Einstein sticking out his tongue. As it happened, the Icarus result was announced on March 16, two days after his 133rd birthday — almost in time for the cake.

Adding to the sense of finality was the simple fact — as Eddington might have pointed out — that faster-than-light neutrinos had never been confirmed by theory. Or as John G. Learned, a neutrino physicist at the University of Hawaii, put it in an e-mail, “An interesting result of all this fracas is that no new model I have seen (or heard of from my friends) really is credible to explain the faster-than-light neutrinos.”

During a panel discussion recently at the American Museum of Natural History, Sheldon L. Glashow, a physics professor and Nobel laureate from Boston University, said the best theory he had heard was that the neutrinos had behaved lawfully in Switzerland and speeded up when they crossed the border into Italy.

Eddington’s dictum is not as radical as it might sound. He made it after early measurements of the rate of expansion of the universe made it appear that our planet was older than the cosmos in which it resides — an untenable notion.

“It means that science is not just a book of facts, it is understanding as well,” explained Michael S. Turner, a cosmologist at the University of Chicago, who says the Eddington saying is one of his favourites. 

If a “fact” cannot be understood, fitted into a conceptual framework that we have reason to believe in, or confirmed independently some other way, it risks becoming what journalists like to call a “permanent exclusive” wrong. 

Read more of this article: The Trouble With Neutrinos - NYTimes.com