Neutrinos still FASTER THAN LIGHT in second test
Take that, Einstein
The boffins who sent sub-atomic particles on a faster-than-light journey into the past have done another successful experiment that confirms the results.
In the original test, 15,000 beams of neutrinos were fired over three years from CERN near Geneva 720km to Gran Sasso in Italy and the particles arrived at their destination 60 nanoseconds faster than they would have it they'd travelled at the speed of light.
In the scientific brouhaha that followed the results going public in September, critics suggested that the beams of neutrinos were rather long, around ten nanoseconds, so margin for error in measuring the time of arrival was quite high.
The researchers determined to present the world with a new physical reality outside of Einstein's theory of general relativity have now sent shorter pulses to improve measurement accuracy.
The new beams were three nanoseconds long and the test left gaps of 524 nanoseconds between them, but they still confirmed the results of the first experiment.
The OPERA (Oscillation Project with Emulsion-tRacking Apparatus) scientists published their results today on arXiv.org.
"A measurement so delicate and carrying a profound implication on physics requires an extraordinary level of scrutiny," Fernando Ferroni, president of Italian Institute for Nuclear Physics (INFN), said in a release on the results.
"The experiment OPERA, thanks to a specially adapted CERN beam, has made an important test of consistency of its result. The positive outcome of the test makes us more confident in the result, although a final word can only be said by analogous measurements performed elsewhere in the world."
Jacques Martino, director of France's National Institute of Nuclear and Particle Physics (CNRS), said another possible error of the experiment, that the clocks at CERN and Gran Sasso were on an ever so slightly different time due to gravitational time dilation, could also be investigated soon.
"One of the eventual systematic errors is now out of the way, but the search is not over. They are more checks of systematics currently under discussion, one of them could be a synchronisation of the time reference at CERN and Gran Sasso independently from the GPS, using possibly a fibre," he said.
Einstein's theory of general relativity allows for time passing at different rates in regions of different gravitational potential. The differences are small, measured in nanoseconds, but could still account for the faster-than-light results. ®
Do you want fries with that?
From the beeb article after the first experiment:
"The scientists are right to be extremely cautious about interpreting these findings," said Jim Al-Khalili, a physicist from the University of Surrey, who suggested that a simple error in the measurement is probably the source of all the fuss.
But he has gone further.
"So let me put my money where my mouth is: if the Cern experiment proves to be correct and neutrinos have broken the speed of light, I will eat my boxer shorts on live TV."
Time to break out the popcorn. I hope he washes them first…
a) The Neutrino detector and emitter are big and heavy and expensive.
b) Because of (a) above there are only a few places on earth where the experiment can be done
c) There is no tunnel between the emitter and the detector, the neutrinos are fired through solid rock, which to a neutrino has all the stopping power of a wet tissue trying to stop a high speed train at maximum velocity.
d) Because of (a) and (c) we can't send light at the same time as the neutrinos
e) Even if we didn't have the problem of (d) because of Heisenberg's uncertainty principle we can't be sure of exactly when the neutrinos left the emitter and arrived at the detector, which is why they use pulses of neutrinos and a lot of Boffin Class Maths to work out the result.
Radio 4 just covered this and trotted out another "physicist" whose name I managed top miss.
According to this authority on the subject light travels at 186,000 miles an hour. something he repeated twice.
Well done the beeb, it takes some doing to be less accurate than Wikipedia.