There was definitely some excitement in the physics world last Fall when the OPERA Collaboration in Gran Sasso, Italy, announced that they had measured neutrinos travelling faster than the speed of light. I've been skeptical of this announcement since the first day, and in the intervening months since, things have been looking worse for the measurement. This culminated last month when the OPERA Collaboration admitted that the faster-than-light measurement may have been due to a simple measurement error.
Now, in what may well be the final nail in the coffin for the claim that neutrinos travel faster than light, scientists from the ICARUS Group, which is also in Gran Sasso, have announced that they've measured neutrinos travelling from CERN, and determined that those neutrinos were not travelling faster than light. The ICARUS detector has been involved in the neutrino findings for several months, and last year pointed out the experimental results showed that the CERN neutrinos did not display the decay pattern expected from neutrinos travelling faster than light.
The ICARUS Detector examined data from neutrinos sent from CERN to Gran Sasso. These neutrinos were from the same pulse that were sent to OPERA, so if the neutrinos were travelling faster than light, the ICARUS detector should have measured that, as well. However, when ICARUS reviewed their data, they found that "The result is compatible with the simultaneous arrival of all the 7 events with the speed of light and not compatible with respect to the result reported by OPERA."
In order to finally verify whether neturinos from CERN are travelling faster than light, CERN will be working with the Gran Sasso laboratories for a final measurement this May.
"The evidence is beginning to point towards the OPERA result being an artefact of the measurement," said CERN Research Director Sergio Bertolucci in a press release, "but it's important to be rigorous, and the Gran Sasso experiments, BOREXINO, ICARUS, LVD and OPERA will be making new measurements with pulsed beams from CERN in May to give us the final verdict."
There's another point in the press release from CERN Director Bertolucci that's worth highlighting as well. "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."
That's absolutely right.
