The test involved clocking the tiny, subatomic particles as they travelled from CERN’s Large Hadron Collider near Geneva to the Gran Sasso National Laboratory in Italy. Last year’s experiment, called OPERA, found the neutrinos taking less time to arrive than light would. Now, however, another Gran Sasso experiment, Icarus, showed neutrinos making the trip at more reasonable speeds.
Last month, it was revealed that a fiber-optic connection problem could have been to blame for showing too short a neutrino time of flight, however, a different factor could mean the timing was off in the opposite direction.
At the time, physicists said they needed to check the experiment very carefully before making a final judgment, and now it’s clear which way things are trending.
“The evidence is beginning to point towards the OPERA result being an artifact of the measurement,” said CERN Research Director Sergio Bertolucci in a statement. Still, the scientists plan to redo the experiment in May and triple-check it.
“Whatever the result, the OPERA experiment has behaved with perfect scientific integrity in opening their measurement to broad scrutiny, and inviting independent measurements,” Bertolucci said. “This is how science works.”
- ICARUS: the neutrino speed discrepancy is 0, not 60 ns (motls.blogspot.com)
- CERN will run a new test to measure neutrino speed – Agenzia Giornalistica Italia (agi.it)