According to those results, a stream of neutrinos fired through the Earth's crust from CERN's Opera experiment on the French - Swiss border was arriving at a detector in northern Italy about 60 nanoseconds sooner than it was expected to arrive. The inescapable conclusion was that the neutrinos were travelling faster than light; something that Einstein was quite sure couldn't happen.
In announcing the results, the researchers also didn't believe them, but having been unable to fault the experiment, they invited other research teams around the world to duplicate the experiment and either agree or disagree with the result.
It turns out that the duplication isn't necessary.
Science Insider (the popular science announcement forum from the American Association for the Advancement of Science) today published a report based on insider knowledge at the detecting facility. They've found the error.
It seems that an optical fibre connector linking the GPS receiver to the primary computer was slightly loose. Testing of the connection found that the mismatched connection was introducing a 60 nanosecond delay into the timing information, thus allowing the neutrinos to *appear* to arrive 60 nanoseconds too soon.
Although still planning to re-run the experiment, the team seems confident that they've slowed their neutrinos back to exactly the speed of light. The Karl Popper inspired falsification of Relativity has fallen at the first hurdle (test and re-test your equipment!).
Oh, and in case you're wondering, a highly accurate GPS receiver is a very useful way to get a properly synchronised time signal for both the sending and receiving stations.