Neutrinos measured going faster than the speed of light

[Master_Ghost_Knight]

So any news about this? Last time it was on the news they said the second test confirmed the first result...great, what now?

Was there a second?

 

[Laurens]

So any news about this? Last time it was on the news they said the second test confirmed the first result...great, what now?

Was there a second?

http://www.guardian.co.uk/science/2011/nov/18/neutrinos-still-faster-than-light?newsfeed=true

 

[Master_Ghost_Knight]

I'm still rather convinced that the timing mechanisms used could have never given the precision requiered to make such measurments. But my hands are of this topic, there are other specialists working in the field and they can launch similar objections, it is still to soon to pont fingers.

 

[borrofburi]

Commenting so I see updates to this thread.

 

[scalyblue]

I thought I read somewhere that somebody accounted for the variance by factoring in GPS lag, afaik there hasn't been a correspoding paper submitted.

 

[australopithecus]

From what I've gathered (mostly from Jim Al-Khalili's tweets), there was a proposed refutation of the FTL neutrinos. That being that they would radiate and lose energy if they had exceeded light speed and this has not been the case.

 

[Squawk]

I'm always a little wary of theoretical disproofs, especially in a case like this for something that was thought to be impossible given relativity.

Plus, we have a physical measurment being disputed because it doesn't agree with theoretical predictions. Whilst I agree it casts doubt, that puts things on very dubious ground. Empiricism FTW.

For what it's worth, I'd hang my hat on a measuring issue that is yet to come to light.

 

[scalyblue]

Found it in my browser history.
http://www.technologyreview.com/blog/arxiv/27260/?ref=rss

Although the speed of light is does not depend on the the frame of reference, the time of flight does. In this case, there are two frames of reference: the experiment on the ground and the clocks in orbit. If these are moving relative to each other, then this needs to be factored in.

So what is the satellites' motion with respect to the OPERA experiment? These probes orbit from West to East in a plane inclined at 55 degrees to the equator. Significantly, that's roughly in line with the neutrino flight path. Their relative motion is then easy to calculate.

So from the point of view of a clock on board a GPS satellite, the positions of the neutrino source and detector are changing. "From the perspective of the clock, the detector is moving towards the source and consequently the distance travelled by the particles as observed from the clock is shorter," says van Elburg.

By this he means shorter than the distance measured in the reference frame on the ground.

The OPERA team overlooks this because it thinks of the clocks as on the ground not in orbit.

How big is this effect? Van Elburg calculates that it should cause the neutrinos to arrive 32 nanoseconds early. But this must be doubled because the same error occurs at each end of the experiment. So the total correction is 64 nanoseconds, almost exactly what the OPERA team observes.

http://arxiv.org/abs/1110.2685

Considering the OPERA neutrino-velocity measurement from the point of view of a GPS satellite we find that the detector at Gran Sasso has a velocity component in the order of $10^{-5}c$ towards the neutrino emission location at CERN. On GPS-receivers this translates into first-order Doppler terms, therefore a correction is required for, among other things, this ephemeris-and-location-dependent relativistic effect. To ensure correct time-of-flight measurements using satellite-based clocks we propose to extend their calibration procedures with an explicit check on these relativistic corrections.

Waiting for some peer review on the refutation.

 

[Master_Ghost_Knight]

I thought I read somewhere that somebody accounted for the variance by factoring in GPS lag, afaik there hasn't been a correspoding paper submitted.

You can't possibly account for the variance of GPS lag because it is by definition unacountable, and there lies the thing that makes me doubt these results.

 

[Deleted member 619]

I'm always a little wary of theoretical disproofs, especially in a case like this for something that was thought to be impossible given relativity.

Plus, we have a physical measurment being disputed because it doesn't agree with theoretical predictions. Whilst I agree it casts doubt, that puts things on very dubious ground. Empiricism FTW.

For what it's worth, I'd hang my hat on a measuring issue that is yet to come to light.

Actually, we don't have a physical measurement being disputed because it doesn't agree with theoretical predictions.

The real problem here is that the measurements have been gauged against a predicted travel time for light, because a measurement of the actual travel time for light over the course of the neutrino path is not possible (photons can't travel through the planet in the same way as neutrinos). Further, some measured events are excluded from the calculations for statistical reasons to do with attempting to eliminate a bias toward early arrival times. What is actually being dealt with here are probability density functions, and it cannot be stated with any degree of certainty which proton is responsible for the emission of a given neutrino. From the paper:

The time of flight of CNGS neutrinos (TOFν) cannot be precisely measured at the single interaction level since any proton in the 10.5 ,µs extraction time may produce the neutrino detected by OPERA. However, by measuring the time distributions of protons for each extraction for which neutrino interactions are observed in the detector, and summing them together, after proper normalisation one obtains the probability density function (PDF) of the time of emission of the neutrinos within the duration of extraction. Each proton waveform is UTC time-stamped as well as the events detected by OPERA. The two time-stamps are related by TOFc, the expected time of flight assuming the speed of light [13]. It is worth stressing that this measurement does not rely on the difference between a start and a stop signal but on the comparison of two event time distributions.

Ultimately, the statistical variables here, coupled with the fact that the measurements are gauged against an expected value of d/c, and further compounded by the very real fact that only a small percentage of the emitted neutrinos are actually detected (due to the well-founded principle that neutrinos are extremely weakly interacting particles), tells me that it's much too early to be sounding the death-knell of special relativity just yet, and I've only dealt with a few of the problems here.

The second paper has certainly addressed one of the objections by dealing in shorter bursts of neutrinos, thus firming up the statistical issues concerned, but it's a long, long way from having addressed all of them.

 

[Laurens]

Suppose there was no measurement inaccuracy and the Neutrinos did exceed c, what do you guys think it might indicate?

 

[)O( Hytegia )O(]

Suppose there was no measurement inaccuracy and the Neutrinos did exceed c, what do you guys think it might indicate?

Quantum Teleportation. Exception to the rule. Many things.

I'll explain it further when not on my phone.

 

[Anachronous Rex]

Suppose there was no measurement inaccuracy and the Neutrinos did exceed c, what do you guys think it might indicate?

We've miscalculated c.

 

[)O( Hytegia )O(]

Suppose there was no measurement inaccuracy and the Neutrinos did exceed c, what do you guys think it might indicate?

We've miscalculated c.

That, too.

But it could mean many things - It's possible that the Neutrino somehow had enough energy or fluctuated in such a way that teleported at brief intervals, becoming energy and reassembling a brief distance at brief intervals between A to B or B to C (A, B, and C being any number of checkpoints they had set up along the way).

Or it could simply be that we just make an exception to the rule and develop a reason WHY it's an exception to the rule.

 

[Deleted member 619]

Suppose there was no measurement inaccuracy and the Neutrinos did exceed c, what do you guys think it might indicate?

Extra dimensions, as per Kaluza-Klein.

 

[nasher168]

We've miscalculated c.

Surely that's impossible, or at least highly unlikely... otherwise radar couldn't work with the extreme accuracy it can.

 

[Anachronous Rex]

We've miscalculated c.

Surely that's impossible, or at least highly unlikely... otherwise radar couldn't work with the extreme accuracy it can.

Well I won't claim to be an expert, but perhaps there is some local factor that is slowing light in proximity to the Earth, but failing to slow neutrinos.

That is to say, it wouldn't be that we're miscalculating the speed at which light is traveling, only the speed that light can travel if it is unimpeded.

That said, I don't really believe this.

 

[Master_Ghost_Knight]

Surely that's impossible, or at least highly unlikely... otherwise radar couldn't work with the extreme accuracy it can.

Radar is not that accurate.

 

[)O( Hytegia )O(]

We've miscalculated c.

Surely that's impossible, or at least highly unlikely... otherwise radar couldn't work with the extreme accuracy it can.

*cough*

Radar has a degree of failure and runs off of non-light EM wave frequencies...