Will faster-than-light neutrino particles bypass Einstein?

Physicists reported that sub-atomic particles called neutrinos can travel faster than light, a finding that – if verified – would blast a hole in Einstein’s theory of relativity.

In experiments conducted between the European Centre for Nuclear Research in Switzerland and a laboratory in Italy, the tiny particles were clocked at 300,006 kilometres per second, about six kilometres per second faster than the speed of light, the researchers said.

“This result comes as a complete surprise,” said physicist Antonio Ereditato, spokesman for the experiment, known as Opera. “We wanted to measure the speed of neutrinos, but we didn’t expect to find anything special.”

Scientists spent nearly six months “checking, testing, controlling and rechecking everything” before making an announcement, he said. The findings, they said, could potentially reshape our understanding of the physical world.

“If this measurement is confirmed, it might change our view of physics,” said CERN research director Sergio Bertolucci, a view echoed by several independent physicists.

In the experiments, scientists blasted a beam producing billions upon billions of neutrinos from CERN, which straddles the French-Swiss border near Geneva, to the Gran Sasso Laboratory 730 kilometres away in Italy.

Neutrinos are electrically neutral particles so small that only recently were they found to have mass.

Hugely abundant but hard to detect, these “ghost particles” are a by-product of nuclear fusion from stars, such as the sun.

“The neutrinos arrived 60 nanoseconds earlier that the 2.3 milliseconds taken by light,” Dr Ereditato said, adding that the margin of error was less than 10 nanoseconds.

Under Albert Einstein’s theory of special relativity, however, a physical object cannot travel faster than the speed of light in a vacuum.

The fact that the neutrinos were moving through matter – including a slice of earth’s crust – could not have caused them to accelerate, said French physicist Pierre Binetruy, who was not involved in the experiment but has reviewed the data.

“It might have slowed them down, but it certainly didn’t make them go faster than the speed of light,” he said.

Dr Binetruy described the results “altogether revolutionary”, and said they will, if backed up, force physicists to go back to the blackboard.

“The theory of general relativity, the theory of special relativity – both are called into question,” he said.

Alfons Weber, a neutrino expert who participated in a similar experiment in 2007 at the US Fermilab, agreed that the faster-than-light neutrinos could not be reconciled with current theories, but said the results needed to be duplicated elsewhere.

“There is still the possibility of a measurement error,” he said by phone. “It would be too exciting to be true. That’s why I’m cautious.”