Neutrino Timing Glitch?
You may recall the kerfuffle last September when physicists connected with the OPERA experiment at the Gran Sasso National Laboratory in Italy produced a paper suggesting that neutrinos might travel at speeds greater than that of light. I posted on that story myself and even composed a poem specially for the occasion at no extra charge:
Do neutrinos go faster than light?
Some physicists think that they might.
In the cold light of day,
I am sorry to say,
The story is probably shite
Well news began to break last night that OPERA scientists had identified an error. The first story I read was a bit shaky on the question of attribution, so I decided to sleep on it and see whether anything emerged that seemed sounder before posting on here. Later on last night an item in Nature News appeared which looks a bit better grounded:
But according to a statement OPERA began circulating today, two possible problems have now been found with its set-up. As many physicists had speculated might be the case, both are related to the experiment’s pioneering use of Global Positioning System (GPS) signals to synchronize atomic clocks at each end of its neutrino beam. First, the passage of time on the clocks between the arrival of the synchronizing signal has to be interpolated and OPERA now says this may not have been done correctly. Second, there was a possible faulty connection between the GPS signal and the OPERA master clock.
We should wait for a more definitive announcement from OPERA about these possible errors, but if it does turn out that technical glitches are responsible for the neutrino speed result then it won’t be entirely unexpected. A faulty cable connection does sound a bit lame, however. I hope they weren’t relying on a USB connection….
Anyway, as I mentioned in a comment elsewhere the arXiv paper from OPERA has now received about 230 citations, although it has not appeared in a refereed journal. If it turns out to have been a completely wrong result, what does that tell you about the use of citations to measure “quality”?
UPDATE: There is now an official press release from CERN, confirming the unofficial reports mentioned above:
Follow @telescoperThe OPERA collaboration has informed its funding agencies and host laboratories that it has identified two possible effects that could have an influence on its neutrino timing measurement. These both require further tests with a short pulsed beam. If confirmed, one would increase the size of the measured effect, the other would diminish it. The first possible effect concerns an oscillator used to provide the time stamps for GPS synchronizations. It could have led to an overestimate of the neutrino’s time of flight. The second concerns the optical fibre connector that brings the external GPS signal to the OPERA master clock, which may not have been functioning correctly when the measurements were taken. If this is the case, it could have led to an underestimate of the time of flight of the neutrinos. The potential extent of these two effects is being studied by the OPERA collaboration. New measurements with short pulsed beams are scheduled for May.
February 23, 2012 at 8:29 am
It may say something about citations. It is well known that a highly visible wrong result attracts attentions and citations. But I would pick out the positive. This result never made it into the refereed literature. Presumably because it was never submitted to a refereed journal, but isn’t that precisely the point? Refereeing works.
February 23, 2012 at 9:55 am
Was anyone offering odds?
February 23, 2012 at 10:59 am
I bet someone was.
February 23, 2012 at 12:08 pm
I’ve been asked to talk about this later on the BBC
February 23, 2012 at 12:55 pm
Turn up early and say you got there too fast
February 23, 2012 at 1:36 pm
That was my plan.
February 23, 2012 at 1:02 pm
Just explain that the neutrinos were offside. But then you’d have to explain the offside rule…
February 23, 2012 at 1:36 pm
The offside rule in rugby? Too complicated to do in 5 minutes.
February 23, 2012 at 1:49 pm
Just say that they came in at the side…
February 23, 2012 at 3:17 pm
Particle physics used to be billiards played near to the speed of light; today it’s snooker or pool played near to the speed of light. (Or slightly faster??) I am not aware of an offside rule in either game.
February 23, 2012 at 7:45 pm
Personally, I fail to see how a faulty connection could possibly explain a 60 nanosecond effect ( equal to 18 m at the speed of light ). Does anyone have any clue?