Special relativity may answer faster-than-light neutrino mystery

Oct 17, 2011 by Tammy Plotner, Universe Today
The relativistic motion of clocks on board GPS satellites exactly accounts for the superluminal effect, says physicist. Credit: axirv

Oh, yeah. Moving faster than the speed of light has been the hot topic in the news and OPERA has been the key player. In case you didn’t know, the experiment unleashed some particles at CERN, close to Geneva. It wasn’t the production that caused the buzz, it was the revelation they arrived at the Gran Sasso Laboratory in Italy around 60 nanoseconds sooner than they should have. Sooner than the speed of light allows!

Since the announcement, the physics world has been on fire, producing more than 80 papers – each with their own opinion. While some tried to explain the effect, others discredited it. The overpowering concensus was the team simply must have forgotten one critical element. On October 14, 2011, Ronald van Elburg at the University of Groningen in the Netherlands put forth his own statement – one that provides a persuasive point that he may have found the error in the calculations.

To get a clearer picture, the distance the traveled is straightforward. They began in CERN and were measured via global positioning systems. However, the Gran Sasso Laboratory is located beneath the Earth under a kilometre-high mountain. Regardless, the OPERA team took this into account and provided an accurate distance measurement of 730 km to within tolerances of 20 cm. The neutrino flight time is then measured by using clocks at the opposing ends, with the team knowing exactly when the particles left and when they landed.

But were the clocks perfectly synchronized?

Keeping time is again the domain of the GPS satellites which each broadcasting a highly accurate time signal from orbit some 20,000km overhead. But is it possible the team overlooked the amount of time it took for the satellite signals to return to Earth? In his statement, van Elburg says there is one effect that the OPERA team seems to have overlooked: the relativistic motion of the GPS clocks.

Sure, radio waves travel at the , so what difference does the satellite position make? The truth is, it doesn’t... but the time of flight does. Here we have a scenario where one clock is on the ground while the other is orbiting. If they are moving relative to one another, this calculation needs to be included in the findings. The orbiting probes are positioned from West to East in a plane inclined at 55 degrees to the equator… almost directly in line with the neutrino flight path. This means the clock on the GPS is seeing the neutrino source and detector as 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.

According to the news source, he means shorter than the distance measured in the reference frame on the ground and the OPERA team overlooks this because it thinks of the clocks as on the ground not in orbit. 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.

Is this the final answer for traveling faster than the speed of light? No. It’s just another possible answer to explain a new riddle... and a confirmation of a new revelation.

Explore further: How the physics of champagne bubbles may help address the world's future energy needs

More information: Time-of-flight between a Source and a Detector observed from a Satellite, arXiv:1110.2685v2 [physics.gen-ph] arxiv.org/abs/1110.2685

Abstract
The Michelson-Morley experiment shows that the experimental outcome of an interference experiment does not depend on the constant velocity of the setup with respect to an inertial frame of reference. From this one can conclude the existence of an invariant velocity of light. However it does not follow from their experiment that a time-of-flight is reference frame independent. In fact the theory of special relativity predicts that the distance between the production location of a particle and the detection location will be changed in all reference frames which have a velocity component parallel to the baseline separating source and detector in a foton time-of-flight experiment. For the OPERA experiment we find that the associated correction is in the order of 32 ns. Because, judging from the information provided, the correction needs to be applied twice in the OPERA experiment the total correction to the final results is in the order of 64 ns. Thus bringing the apparent velocities of neutrino's back to a value not significantly different from the speed of light. We end this short letter by suggesting an analysis of the experimental data which would illustrate the effects described.

via Technology Review

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User comments : 17

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Jose_X
not rated yet Oct 17, 2011
[IANA physicist. I skimmed the papers]

The rebuttal paper assumes the measuring clocks were on the satellites, but they were on the earth. Both labs synchronized using the satellite. Now, while the sync might have been flawed, it has been stated for years that such a sync can produce accuracy to about 1ns.

I am guessing the problem might be that the instrument delay times during the sync calibration were different than during the experiment. This could account for faster or slower neutrino times. This might also be possible since the system GPS sync was updated in 2008 and perhaps not all design time constraint assumptions have been retested (including maybe software upgrades if any). I think a different delay path could be used for syncing and then for testing.

However, the values of the Lorentz transform from the rebuttal did come really close to the 60ns.

Also, iirc, the neutrino data was taken over multiple years. The PDF of the transit times might be skewed from subset errors?
Matt2020
5 / 5 (1) Oct 17, 2011
Seems too simple an explanation to me.
I'm sure that some time during the years and millions spent checking these results, someone would have got two clocks synchronised at the mid point, and moved them to each end of the experiment.
What am I missing?
rawa1
1.2 / 5 (5) Oct 17, 2011
Whereas I'm rather convinced supporter of superluminal neutrino model, it's true, these experiments are based on dozens of corrections, many of them are much larger, than the difference observed. But we shouldn't forget, to impeach experiments is always a much easier, than to replicate them.

As one of indicia, that the OPERA results cannot be ignored so easily, can serve the fact, these experiments fits well previous results.

http://www.scienc...ini2.jpg
Bowler_4007
not rated yet Oct 17, 2011
@Matt2020, When you think about the problem is actually very basic, it therefore follows that the answer could be simple with tiniest of details making the crucial difference between which is really faster.

It could also be that the neutrinos are faster and the problem is much less basic than we realise.

Fact is people aren't ready to give up on >c speeds so we'll continue to scruntinize this problem until we're blue in the face.
rawa1
1.2 / 5 (6) Oct 17, 2011
My explanation of superluminal neutrinos is based on water surface analogy of space-time. The particles are spreading along it like the soliton wave, which makes more dense/curved both the water surface, along which such soliton is rolling, both the underwater.

The exception of neutrinos consist of the fact, they're very weak and subtle solitons, so that accidental fluctuations of underwater can occasionally wipe out the effect of surface deformation. Under such a situation, the neutrino propagates like underwater sound wave exclusively, i.e. much higher speed, than the surface ripples. During these rare moments the spreading of neutrino is literally detached from water surface, so it can propagate higher speed. This situation is the more probable, the higher speed the neutrino is - whereas low energy neutrinos would propagate in normal subluminal speed.
rawa1
1 / 5 (5) Oct 17, 2011
In dense aether theory the space-time is modeled with phase interface of supercritical fluid and after then the photons are subluminal solitons resulting from mutual interference of transverse waves with bulk waves of heavier phase and the neutrinos are superluminal solitons resulting from mutual interference of transverse waves with bulk waves of lightweight phase. It means, we always have two kinds of solitons here, one tends to propagate with slightly subluminal speed (photons), whereas the second one is propagating in slightly superluminal speed (neutrinos).

This model is slightly complicated with fact, the space-time is not completely flat due the presence of CMBR fluctuations, so that the low energy neutrinos can still propagate with subluminal speed, until their energy is not higher, than the energy of CMBR photons. And the photons can spread with slightly superluminal speed, until their energy (i.e. frequency) is not higher, than the energy/frequency of CMBR photons.
hush1
1 / 5 (1) Oct 17, 2011
All satellites have redundancy. Have the satellites used, ever use that redundancy? When I say say redundancy I mean the software written for redundancy as well as hardware the redundancy is written for.
Foolish1
5 / 5 (1) Oct 17, 2011
If the effect is the same on both GPS receivers wouldn't the effect cancel from the perspective of clock synchronization rather than reinforce? One end would have to show a positive discrepancy and the other negative. If the discrepancy is the same sign the clocks are both skewed by the same amount and remain synchronized.

Why do you have to account for the delta in realitivistic distance between ground and sat references to each other? The GPS system already transmits a slower timing signal to account for time difference between sat and ground.
GrayMouser
1 / 5 (1) Oct 19, 2011
"The Michelson-Morley experiment shows that the experimental outcome of an interference experiment does not depend on the constant velocity of the setup with respect to an inertial frame of reference."
I don't think they read the same publication I read. The M-M experiment showed a variable velocity of light dependent on altitude. The results were published in Science in 1905 with great detail on the experimental setup and the analysis of the collected data.
rawa1
1 / 5 (1) Oct 19, 2011
he M-M experiment showed a variable velocity of light dependent on altitude
It just illustrates, everyone can see what he wants in results of physical experiments. For example the common gravitational lensing can be interpreted both like result of heavy violation of constant speed of light during its spreading through vacuum, both like the confirmation of it, when tiny density gradients are taken into account. It just depends on your phillosophy, which perspective you will prefer.

http://www.aether...vity.gif

In general, the perspective based on breaking of symmetries enables to understand their connections deeper, whereas the perspective based on symmetries enables you to describe these connections more exact. It's tic-for-tac situation, which people should consider even when discussing another aspects of reality, including the politics, biology and social sciences. The more exact theories are less predicative and vice-versa.
rawa1
1 / 5 (1) Oct 19, 2011
The ICARUS experiment claims to refute the superluminal neutrinos finding at OPERA http://www.scienc...os-83684 with absence of Cherenkov radiation.

My stance is, for chargeless neutrinos the analogy with charged particles cannot be applied - on the contrary, these neutrinos are moving with superluminal speed in brief moments of their life just because they're losing their charge during this (while changing into sterile Majorana neutrinos in this way). No charge - no radiation into outside.
John_Stevenson
1 / 5 (2) Oct 19, 2011
If light travels in waves, and neutrinos travel in a straight line, would this account for their seemingly early arrival?
Callippo
1 / 5 (1) Oct 19, 2011
If light travels in waves, and neutrinos travel in a straight line, would this account for their seemingly early arrival?
This idea would introduce the dependence of speed of light waves on their amplitude (i.e. the intensity of light) - which we don't observe. In general, the speed of waves on strings is independent to their amplitude (for example, the tune of guitar sound doesn't depend on its loudness) - why the light should be an exception?
unknownorgin
1 / 5 (2) Oct 19, 2011
I do not see why GPS is used in this experiment. If a detector is placed at the starting point and the destination point then a high speed timer is at the exact middle and signal travel length is the same from both ends to the timer after subtracting for time slowing down at the underground lab there is no place for error to occurr.
Callippo
1 / 5 (1) Oct 20, 2011
then a high speed timer is at the exact middle
Define the "exact middle" with 18 cm precision without GPS. And how to drill the hole there?
Ober
not rated yet Oct 22, 2011
If light travels in waves, and neutrinos travel in a straight line, would this account for their seemingly early arrival?
All matter/energy travel as both a wave and particle. See De Broglie.

http://en.wikiped...ter_wave
Daleg
not rated yet Oct 23, 2011
The issue here again is that we live in a nominaly warped space due to relative motion. What the article is refrencing is the Lorentz contraction, which is a standard feature of special relativity, the basic idea is that distance will be shorter along the line of travel for any object moving at or near light speed. None of this has to do with any other property of Nuetrinos, Light or any other form of energy other than the relative speed as measured in the reference frame of the particle. If Einstein's theory is correct, and M/M measurements give a big hint that it is, then all energy will exhibit this effect. Whether the GPS was properly correlated or not, if the system was not designed to account for the error from the beginning the error will be a fixed constant for every measurement. It does seem simpler than likely, but is exactly the kind of close scrutiny these types of results require, before one can be 100% certain they are true, and not caused by systematic error.

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