Neutrino evidence against “faster-than-light” claim
Neutrinos do not go faster than light, according to new measurements made by an experiment called ICARUS at the Gran Sasso Laboratory using a new measuring technique, called a liquid argon time projection chamber and working independently from the OPERA scientists who had made the tentative but extremely controversial claim about “faster-than-light” particles. Particles that travel faster than light would unravel Albert Einstein’s 1905 theory of special relativity, a cornerstone of modern physics.
Their findings “indicate the neutrinos do not exceed the speed of light,” the European Centre for Nuclear Research (CERN) said, ading that there may have been technical hitches that had skewed the initial measurements, something that skeptics of the findings said they had always suspected.
The controversy began last September, when CERN’s so-called OPERA team cautiously announced that sub-atomic particles called neutrinos had travelled some six kilometres (nearly four ) per second faster than the velocity of light, described by Einstein as the maximum speed in the cosmos.
The neutrinos were timed at their departure from CERN’s giant underground lab near Geneva and again, after travelling 732 km (454 miles) through the Earth’s crust, at their arrival at the Gran Sasso Laboratory in Italy.
To complete the trip, the neutrinos should have taken 0.0024 seconds. Instead, the particles were recorded as hitting the detectors in Italy 0.00000006 seconds sooner than expected.Knowing their findings would create a global controversy, the OPERA team urged other physicists to carry out their own checks to corroborate or refute what had been seen.
“ICARUS measures the neutrino’s velocity to be no faster than the speed of light,” said Carlo Rubbia, a Nobel winner and spokesperson for the ICARUS project..”Whatever the result, the OPERA experiment has behaved with perfect scientific integrity in opening their measurement to broad scrutiny and inviting independent measurements. This is how science works,” said CERN Research Director Sergio Bertolucci, who added that further verifications were being made, including new experiments with particle beams in May, “to give us the final verdict.”
In February, CERN said that the OPERA team were verifying a cable connection and a timing instrument called an oscillator that may have flawed measurements of the neutrinos’ flight time.Strengthening this scenario, Bertolucci said on Friday “the evidence is beginning to point towards the OPERA result being an artifact of the measurement.”