18 November 2011

Further Proof That Neutrinos Faster Than Light?

Last month it was reported that a team of scientists had discovered neutrinos traveling faster than the speed of light. The BBC reports that the team have run an improved version of the original experiment and have replicated their original results

Critics of the first report in September had said that the long bunches of neutrinos (tiny particles) used could introduce an error into the test.
The new work used much shorter bunches ( This I do not understand but physicists will be able to explain, I'm sure).

However, the new findings, although submitted to the Journal of High Energy Physics, have not yet been peer-reviewed and a lot of further verification is required.

The experiments have been carried out by the Opera collaboration - Oscillation Project with Emulsion (T)racking Apparatus. It hinges on sending bunches of neutrinos created at the Cern facility  through 730km (454 miles) of rock to a giant detector at the Gran Sasso laboratory in Italy.

The initial series of experiments, comprising 15,000 separate measurements spread out over three years, found that the neutrinos arrived 60 billionths of a second faster than light would have, traveling unimpeded over the same distance.

Initial analysis of the work by the wider scientific community argued that the relatively long-lasting bunches of neutrinos could introduce a significant error into the measurement. Those bunches lasted 10 millionths of a second - 160 times longer than the discrepancy the team initially reported in the neutrinos' travel time.

To address that, scientists at Cern adjusted the way in which the neutrinos were produced, resulting in bunches just three billionths of a second long.
When the Opera team ran the improved experiment 20 times, they found almost exactly the same result.

"This is reinforcing the previous finding and ruling out some possible systematic errors which could have in principle been affecting it," said Antonio Ereditato of the Opera collaboration. "We didn't think they were, and now we have the proof... This is reassuring that it's not the end of the story."

The Opera collaboration is very aware of its implications if eventually proved correct. The error in the length of the bunches, however, is just the largest among several potential sources of uncertainty in the measurement, which must all now be addressed in turn; these mostly centre on the precise departure and arrival times of the bunches.

"So far no arguments have been put forward that rule out our effect," Dr Ereditato said.:This additional test we made is confirming our original finding, but still we have to be very prudent, still we have to look forward to independent confirmation. But this is a positive result."

That confirmation may be much longer in coming, as only a few facilities worldwide have the detectors needed to catch neutrinos.Next year, teams working on two other experiments at Gran Sasso experiments - Borexino and Icarus - will begin independent cross-checks of Opera's results. The US Minos experiment and Japan's T2K experiment will also test the observations. It is likely to be several months before they report back.

High energy physics is a mystery to me, but then  so is physics in general! If the results can be replicated (all all possible sources of error are a;;owed for_ the we might just be seeing a true (and in the meaningless  management techno babble sense) paradigm shift. I won't hold my breath though. Verification or otherwise may take years, while applications arising from the discovery may take many more decades to see the light of day..

Still one can dream of a Star Trek universe - one without the Borg, the Dominion and the Romulans would be preferable though!

6 comments:

Andrew said...

The big problem though is the 1987 supernova (put that into Google for fantastic images), whose neutrinos arrived a little later than the light, exactly as expected. The much more likely explanation remains some overlooked anomaly in the experiment, unless travelling through rock makes a difference. My son is working in the cavern deep under that mountain at Gran Sasso as I type. Not that I am attributing my views to him, of course. They are all mine. My boy was born in 1987 too, alongside the arrival of the signals from the supernova. It all means something, or nothing.

jams o donnell said...

Thanks for this Andrew. It would be amazing to think that they are correct but I am sure there are plenty of anomalies that need to be resolved.. and these will probably explain it.. Still one can dream!

Sean Jeating said...

... not to forget the tachyons ...

Where's Sheldon Lee Cooper when ... ?

jams o donnell said...

AH the guy from The Big Bang Theory... where indeed!

SnoopyTheGoon said...

Whatever the outcome, it certainly wouldn't be a paradigm shift (actually I am not sure what paradigm shift means, and I suspect no one is).

Just the way physics go - expansion instead of rejection of previous achievements.

jams o donnell said...

I was thinking of a change in our basic assumptions. If neutrinos can travel further than light that changes the view that nothing can travel faster than light. A huge change, if true.

I daresay that there are anomalies or errors that give rise to the result but one can still dream!