Extraordinary Neutrinos

“Extraordinary claims require extraordinary evidence.”

Carl Sagan’s famous quote surfaced aplenty last week as European researchers made extraordinary claims about neutrinos traveling faster than the speed of light.

Why the fuss? Because it terribly upsets physics models, ScienceNOW explains:

If so, the observation would wreck Einstein’s theory of special relativity, which demands that nothing can travel faster than light.

Here’s the background to the debate. Scientists, working with the OPERA (Oscillation Project with Emulsion-tRacking Apparatus) experiment, reported neutrinos traveling 450 miles (730 km) in 2.43 milliseconds—60 nanoseconds faster than light, with a margin of error of ±10 nanoseconds.

Over 15,000 neutrinos were tracked—beginning at CERN outside of Geneva, Switzerland, and ending at OPERA, 4,500 feet (or 1,400 meters) underground at Gran Sasso, Italy, in that short time. The physicists measured distance between the origin of the neutrino beam and OPERA with an uncertainty of 20 cm over the 730 km travel path. They accurately determined the neutrinos’ flight time using sophisticated instruments, including advanced GPS systems and atomic clocks. The time response of all elements of the CNGS (CERN Neutrinos to Gran Sasso) beam line and of the OPERA detector has also been measured with great precision.

“This result comes as a complete surprise,” said OPERA spokesperson Antonio Ereditato of the University of Bern. “After many months of studies and cross checks we have not found any instrumental effect that could explain the result of the measurement. While OPERA researchers will continue their studies, we are also looking forward to independent measurements to fully assess the nature of this observation.”

The researchers presented their findings at seminar full of skeptics last week. In fact, the researchers themselves remain skeptical! “The potential impact on science is too large to draw immediate conclusions or attempt physics interpretations. My first reaction is that the neutrino is still surprising us with its mysteries.” said Ereditato. “Today’s seminar is intended to invite scrutiny from the broader particle physics community.”

“When an experiment finds an apparently unbelievable result and can find no artifact of the measurement to account for it, it’s normal procedure to invite broader scrutiny, and this is exactly what the OPERA collaboration is doing, it’s good scientific practice,” said CERN Research Director Sergio Bertolucci. “If this measurement is confirmed, it might change our view of physics, but we need to be sure that there are no other, more mundane, explanations. That will require independent measurements.”

Most physicists are skeptical (take, for example, the doubts voiced by “physics luminaries” on the Scientific American website), although one was quoted in ScienceNOW as saying, “I’d be delighted if it were true.” And those of you with high tolerance for general relativistic equations and extra dimensions can check out a theoretical paper released on Monday that considers how to explain the results. We’re looking forward to some extraordinary evidence… In the meantime, we’ll settle for some extraordinary jokes about this finding.

For more general info on neutrinos, check out this great primer from New Scientist.

Image from the OPERA website