CERN team claims measurement of neutrino speed >c

[Drakkith]

If we take the altitude of Cern, Switzerland and the altitude of Gran Sasso, Italy, what would be the difference in clock rates between the two locatons due to gravitational time dilation? Has this been factored into the experiment? I believe this is critical and I don't think the difference could be accurately determined.

I'm about 99% sure that has already been taken into account if it needs to be. And yes, it can be accurately determined.

 

[nitsuj]

And yes, it can be accurately determined [gravitational time dilation].

Do you think the distance can be (was) accurately determined? How far off was the speed from c in distance?

 

[Drakkith]

Do you think the distance can be (was) accurately determined? How far off was the speed from c in distance?

The distance between Cern and Gran Sasso? And what speed? The neutrino's?

 

[Vanadium 50]

Looks like it's that time again.

Before posting in this thread, we'd like to ask readers to read three things:

• The PF Rules. Don't forget the section on overly speculative posts.
• The paper http://arxiv.org/abs/1109.4897
• he previous posts in this thread

We think this will make the discussion go smoother.

V50, for the Mentors.

 

[e2m2a]

Looks like it's that time again.

Before posting in this thread, we'd like to ask readers to read three things:

• The PF Rules. Don't forget the section on overly speculative posts.
• The paper http://arxiv.org/abs/1109.4897
• he previous posts in this thread

We think this will make the discussion go smoother.

V50, for the Mentors.

Thanks for the reference to the paper. My question has been answered in the paper as stated: "The gravitational red-shift due to the different CERN and LNGS altitudes produces an even smaller relative effect of 10-13 on the clocks in between two common-view synchronisations."

 

[e2m2a]

Could the measurement process have affected the measurement? (That is, are we looking at a sort of Heisenberg effect, where our observation of the neutrinos is somehow affecting timing in a way that we haven't figured out?)

neopolitan

I believe neopolitan has brought up an interesting point that has not been discussed in full. What are the scientists claiming? That they have measured neutrinos traveling faster than c. Here's the essential point. What speed? An average speed or an instantaneous speed?

Newton showed us centuries ago that average speed and instantaneous speed are not necessarily the same. They are the same if we assume a priori that the instantaneous speed is the same at every point on the path of travel of an object's speed we are measuring.

To claim a neutrino is traveling faster than a photon we would have to take an instananeous velocity measurment of that neutrino. An instantaneous velocity measurement would require an infinitesimally small distance between two clocks -- essentially a point.

Now, enter the Heisenberg Uncertainty Principle. The neutrino's dimensions are in the realm of quantum physics, and so it must conform to HUP. If there were a way that we could absolutely measure this "point", the infinitesimally small distance between the two clocks, we could not by HUP precisely determine the momentum of that neutrino at that point, or the velocity at that point. HUP forbids it.

This being the case, it wouldn't matter if the experiment could eliminate all systemic measurement errors, there still would be an inescapable uncertainty in the instantaneous speed of the neutrino.

One might argue, an instantaneous velocity measurement is not being measured in this experiment, and so HUP doesn't apply. Well, this would assume an average velocity is being measured then.

However, if you sliced the path of travel of the neutrino into an infinite number of infinitesimally small increments, each slice would have an inescabable uncertainty in measuring the instantaneous velocity of the neutrino.

Add all these uncertainties up. Could we then claim we have an absolute certain measurment of average velocity of the neutrino for the distance between Cern and Gran Sasson, even though we could never attain a certain measurement of the neutrino's instantaneous velocity at every point along its path between Cern and Gran Sasson?

It seems like a paradoxical contradiction.

 

[Drakkith]

Because of the extremely low interaction rate with normal matter, neutrinos are notoriously hard to detect. I believe we measure when their pre-decay particles cross a boundary right before they decay, and then measure the time it takes to detect them at the detector and compare the clocks, obviously correcting for all the different effects. With particles that are very short lived and have decay products including a neutrino, they can take lots and lots of measurements and average them all out to get a value very close. More measurements means a closer value.

I only had a quick glance at the description of the experiment, so I could be a little off in this, but I think that's how it works.

 

[feathermoon]

Chandler wobble, annual wobble, shifting tectonic plates--could either of the laboratories be not where they think they are?

 

[Drakkith]

Chandler wobble, annual wobble, shifting tectonic plates--could either of the laboratories be not where they think they are?

The possibility exists, yet I think it is exceedingly unlikely they just didn't take something like this into account.

 

[rorix_bw]

@e2m2a: No velocity was measured. They took a time of flight measurement and calculated the velocity by the time taken to travel a known distance.

 

[e2m2a]

@e2m2a: No velocity was measured. They took a time of flight measurement and calculated the velocity by the time taken to travel a known distance.

Velocity is defined as a known distance divided by a time of flight measurement, isn’t it?

Measuring the coincidence of a neutrino or neutrinos at each of the points of the experiment, the starting and ending points at CERN and Gran Sasso, to start a clock and stop a clock, would involve a complication due to the wave-particle duality of sub-atomic particles as defined by De Broglie.

The neutrino(s) cannot just be viewed as a particle or particles in the classical sense. They also have wave-live properties. This being the case, how could one absolutely know where the neutrino or neutrino cluster is with respect to a starting clock and an ending clock to accurately start and stop the clocks? How could you do this with a wave-particle?

I think this prevents any accurate determination of the velocity of the neutrino(s) between Cern and Gran Sasso.

And even if HUP has nothing to do with this experiment, why would nature allow a particle to attain superluminal speed, but only at a fraction above the speed of light? Why not twice or three times the speed of light? Why only a fraction? What fundamental law would dictate this?

This points to a measurement error in my opinion, if HUP does not apply here.

I think all of this has already been determined as mentioned earlier in this thread by others. Light and neutrinos from a distant super-nova explosion have arrived nearly simultaneously at earth. If the neutrinos could outrace the photons, they had more than ample time and space to do this, but they didn’t.

 

[Buckleymanor]

The neutrino(s) cannot just be viewed as a particle or particles in the classical sense. They also have wave-live properties. This being the case, how could one absolutely know where the neutrino or neutrino cluster is with respect to a starting clock and an ending clock to accurately start and stop the clocks? How could you do this with a wave-particle?

I think this prevents any accurate determination of the velocity of the neutrino(s) between Cern and Gran Sasso.

You could use the same argument with regards to light.It too has both particle and wavelike qualities but that don't stop us defineing it's speed.
It won't really matter if what you send is a particle or wave so long as you knew when you first sent it and when it first arrived.

 

[rorix_bw]

@e2m2a:

Yes, there probably is an error, but, I don't think you've found it. I was going to write but the previous poster BuckleyManor said what I wanted to say on this.

As for why is the value only very slightly higher, true, that is "suspicious" but so are a lot of other things.

 

[ondine]

While there is a high degree of sensationalism in the media with this story, it wouldn't be in CERN's best interest to tout a discovery of this magnitude if it could be so easily disproved by allegations of measurement error.

I think there's natural reflex to deny these results; even I'm willing to bet that a follow up news story and an apology by CERN will be appearing on the BBC in a month or two. That being said, I think we're better off discussing the implications of the results if they do turn out to be true, rather than struggling to disprove what some of the greatest minds in physics are claiming they've discovered.

 

[danR]

.
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That being said, I think we're better off discussing the implications of the results if they do turn out to be true, rather than struggling to disprove what some of the greatest minds in physics are claiming they've discovered.

I wouldn't say exclusively 'better off', and I don't think they regard themselves as doing much more than putting forth curious data which they could not account for.

But I would agree that the discussion has been overwhelmingly focussed on measurement-error, or 'it-can't-be-true, because...'; or n00bish 'this would be cool, because it proves time-travel', 'Einstein's been dethroned', and so forth.

A tiny fraction here, and elsewhere, ask what happens if it is true, and does it really require superluminal signaling (vs group-velocity), and is there a simple explanation, does it involve propagation through dense matter vs a vacuum (SN1987a evidence), etc.

 

[lalbatros]

While there is a high degree of sensationalism in the media with this story, it wouldn't be in CERN's best interest to tout a discovery of this magnitude if it could be so easily disproved by allegations of measurement error.

I think there's natural reflex to deny these results; even I'm willing to bet that a follow up news story and an apology by CERN will be appearing on the BBC in a month or two. That being said, I think we're better off discussing the implications of the results if they do turn out to be true, rather than struggling to disprove what some of the greatest minds in physics are claiming they've discovered.

The struggle to disproof the result should at least match the effort made to get this result.
The fact that big teams and big minds came to this temptative conclusion only strengthen the effort that should be done to disrpoof it.
In addition, this OPERA experiment involves several different fields which make the whole thing even more risky.

 

[feathermoon]

Are matter wavelengths a function of energy available at production, like photon wavelengths are? Not suggesting anything, the discussion just made me wonder.

 

[lalbatros]

Are matter wavelengths a function of energy available at production, like photon wavelengths are? Not suggesting anything, the discussion just made me wonder.

Absolutely, this is quantum mechanics!

http://en.wikipedia.org/wiki/Matter_wave

 

[rorix_bw]

When will the labs be able to verify this? Fermilab have said they will. The Japanese lab was damaged by earthquake. How long for repairs?

 

[OnlyMe]

When will the labs be able to verify this? Fermilab have said they will. The Japanese lab was damaged by earthquake. How long for repairs?

It was my understanding that Fermilab was upgrading some equipement necessisary to duplicate the experiment. It sounded like that was mostly timing issues. I don't know how long that will take.

I also understood that CERN was to make a proton stream available to re-run the short burst experiment sometime this year. They ran a very short test of principle experiment after the first data had been released. That data is in the newer paper.

I don't know about Japan. I did hear that they thought they might have some existing historical data they could look at, but having heard nothing on that it does not sound like it panned out.

 

[Adel Makram]

The thing is that the CERN experiment will not change the fact that the SR is not appealing. If proved that CERN was right this will through SR into the forgetfulness, and if wrong, still SR is not grand working theory. Something went unusual in the history of the special relativity. Einstein considered the negative result of Michelson and Murray (MM) experiment as a postulate upon which he created the theory of relativity. Instead of explaining why the speed of light (C) is invariant according to MM, he regarded it as an initial hypothesis. This is really odd in the history of science where the result is taken as a postulate,,, generally speaking there is nothing against postulating anything to build up a new theory, but that would rank it down

 

[thenewmans]

I just watched NOVA Ghost Particle and it got me thinking. The problem is my brain isn’t strong enough to hold all that I’m reading about this experiment.

From what I gather, the CERN end of the experiment generates pions which decay into muons and muon neutrinos. According to that NOVA episode, electron neutrinos eventually oscillate into other neutrino flavors. If they’re traveling at the speed of light, they wouldn’t have time to oscillate. This 2001 discovery required a change to the standard model so that neutrinos have mass and do not travel at the speed of light. I don’t know if the Gran Sasso detector can distinguish between neutrino flavors. But working logically backwards, I assume that would help in determining the speed of the neutrinos. Does that make sense?

Here’s another thing. If the neutrinos travel at or above the speed of light, I assume they must have been going that fast back when they were created from the pions. So either the pions were going that fast or the decay must have given the neutrinos a little speed boost. And that boost must have been in the direction of travel. I would expect a lot of the neutrinos to get boosted in different directions, which would cause a lot of them to miss the target. And in that case, I would expect the detector to pick up far fewer neutrinos than predicted. Does any of this make sense?

 

[Parlyne]

The thing is that the CERN experiment will not change the fact that the SR is not appealing. If proved that CERN was right this will through SR into the forgetfulness, and if wrong, still SR is not grand working theory. Something went unusual in the history of the special relativity. Einstein considered the negative result of Michelson and Murray (MM) experiment as a postulate upon which he created the theory of relativity. Instead of explaining why the speed of light (C) is invariant according to MM, he regarded it as an initial hypothesis. This is really odd in the history of science where the result is taken as a postulate,,, generally speaking there is nothing against postulating anything to build up a new theory, but that would rank it down

Even if these results are confirmed, SR will no more disappear than Newtonian mechanics has. The fact that predictions involving SR have, in at least certain situations, been confirmed to 11 decimal places seems to be a pretty good indication that it is extremely useful, even if it turns out not to be exactly correct.

Also, Einstein made no reference to the Michelson Morley experiment in his original paper; and, it is not entirely clear whether he knew about it at all at that time. His original postulates are based more on the theoretical understanding of Maxwell's equations and of inertia than on specific results in the search for the ether.

 

[OnlyMe]

Even if these results are confirmed, SR will no more disappear than Newtonian mechanics has. The fact that predictions involving SR have, in at least certain situations, been confirmed to 11 decimal places seems to be a pretty good indication that it is extremely useful, even if it turns out not to be exactly correct.

Also, Einstein made no reference to the Michelson Morley experiment in his original paper; and, it is not entirely clear whether he knew about it at all at that time. His original postulates are based more on the theoretical understanding of Maxwell's equations and of inertia than on specific results in the search for the ether.

While it is also my understanding that Einstein may not have been aware of the Michelson and Morley experiments, he was aware of at least some of the experimental attempts to discover the Earth's motion relative to the ether. (there were other attempts both before and after M&M.) from the beginning of the second paragraph of his 1905 paper on SR, "... with the unsuccessful attempts to discover any motion of the Earth relatively to the ``light medium,'' . (a trivial distinction...) Additionally, the way I read that paper, it really only established that the ether was not necessisary to explain experience, not that it did not exist.

To ward off any misunderstanding on my previous point.., the ether as it was understood at the time, most certainly does not exist and is not consistent with what we have come to know of the universe in the last 100 years.

That aside, you are correct in that even should the FTL neutrino results be confirmed, SR is safe. It would not even have any implications for any other know particles or certainly not for matter.

Though the neutrino has a small mass it is a neutral particle that interacts only weakly with matter. There are a few models suggesting that inertia is an emergent phenomena of QM. Sould that be the case, from the few I have been reading about, it is not certain that a neutrino at any speed would be subject to the same emergent interactions, with vacuum energy and would then be limited in velocity only by the manner and energy, present at the time of its "creation". (bad phrasing.)

It could even lead to a whole new approach and understanding of the mechanisms behind inertia itself.

 

[lalbatros]

The thing is that the CERN experiment will not change the fact that the SR is not appealing.

This is not an appealing statement to anyone interrested in the scientific method!
It is even less a fact!

Just try for yourself: remove any reference to SR from any part of physics.
What will you observe then?
The whole modern physics would collapse.

Just to take one example, my preffered one.
Have you ever read about the Mossbauer effect?
As a student, I had the opportunity to perform a simple Mossbauer experiment in a lab.
I found the experiment as well as the analysis, based on SR, extremely appealing.
I know nobody who would disagree.
I can also make un-scientifc statements: I felt in love with this Mossbauer experiment.

 

[TrickyDicky]

This is not an appealing statement to anyone interrested in the scientific method!
It is even less a fact!

Just try for yourself: remove any reference to SR from any part of physics.
What will you observe then?
The whole modern physics would collapse.

Just to take one example, my preffered one.
Have you ever read about the Mossbauer effect?
As a student, I had the opportunity to perform a simple Mossbauer experiment in a lab.
I found the experiment as well as the analysis, based on SR, extremely appealing.
I know nobody who would disagree.
I can also make un-scientifc statements: I felt in love with this Mossbauer experiment.

How is the Mossbauer effect specifically related to relativity?

 

[lalbatros]

How is the Mossbauer effect specifically related to relativity?

The most strinking relation is with GR, since the effect of gravity has been detected by a Mössbauer experiment.
However the transverse Doppler effect, a SR effect, has also been observed by a Mössbauer experiment.


See also: http://what-when-how.com/physicists/mossbauer-rudolf-ludwig-physicist/

 

[TrickyDicky]

Ok, but I asked how. Can you explain what is the direct connection between recoil-free nuclear resonance and special or general relativity?

 

[lalbatros]

Emitter and absorber placed at different gravity potential have slightly different characteristic frequencies.
The Mossbauer effect can reveal very such small differences.

The basic benchtop Mossbauer experiment uses rather small velocities obtained with loudspeaker-like equipment and show very clear effects on transmission. This what I had the opportunity to play with as a student.

Transverse Doppler effect proceeds in the same way and illustrates SR in a unique way.

 

[Aether]

That aside, you are correct in that even should the FTL neutrino results be confirmed, SR is safe. It would not even have any implications for any other know particles or certainly not for matter.

The Cohen-Glashow paper, in view of the ICARUS results, implies that, should the FTL neutrino results be confirmed, then electrons and/or positrons would have to be capable of FTL travel as well.

 

[Adel Makram]

Even if these results are confirmed, SR will no more disappear than Newtonian mechanics has. The fact that predictions involving SR have, in at least certain situations, been confirmed to 11 decimal places seems to be a pretty good indication that it is extremely useful, even if it turns out not to be exactly correct.

Also, Einstein made no reference to the Michelson Morley experiment in his original paper; and, it is not entirely clear whether he knew about it at all at that time. His original postulates are based more on the theoretical understanding of Maxwell's equations and of inertia than on specific results in the search for the ether.

if CERN proved true, it will not only disqualify SR based on supraluminal travel but also because it implies that C is not invariant ,,, Even in Einstein own words “ if c proved not invariant, SR and GR would collapse like a castle of cards”
SR can not be dealt on the same footing as Newton mechanics. If you want similar example, you may consider quantum mechanics. Both Newton and quantum mechanics introduced a physical functions to build up theories. That was the concept of force f=ma in Newton approach and the concept of wave function in case of QM.

 

[Parlyne]

if CERN proved true, it will not only disqualify SR based on supraluminal travel but also because it implies that C is not invariant ,,, Even in Einstein own words “ if c proved not invariant, SR and GR would collapse like a castle of cards”
SR can not be dealt on the same footing as Newton mechanics. If you want similar example, you may consider quantum mechanics. Both Newton and quantum mechanics introduced a physical functions to build up theories. That was the concept of force f=ma in Newton approach and the concept of wave function in case of QM.

You are completely missing my point. If you ask an engineer to design a bridge, he's not going to go use GR and Quantum Mechanics, he's going to use Newtonian physics because it is indistinguishable from more correct pictures of physics at the precision relevant for bridge building. Similarly, even if the OPERA results are validated, SR will still be used for a great many applications because it is indistinguishable from whatever more correct physics replaces it at the precision necessary for those applications. That was my point about precision measurements. SR has worked well enough for those so far; so, a more correct theory is only needed when the precision becomes so great that the theories become distinguishable.

 

[Adel Makram]

the work in theoretical physics does not and will not aim to improve the accuracy of measurement to any degree of precision. If it does, then the Heisenberg notation of Matrix representation of QM might not be needed as long as the wave-representation was enough to get into the same results. The work in theoretical physics rather deals with hypothesis that may be even impossible to validate it experimentally, yet still has a beautiful logic to work on it.

 

[feathermoon]

Is there any information on a marked energy difference for the pion's other decay products? Are the Muons lower in energy than expected, or higher perhaps?

 

[Adel Makram]

Recently, one has claimed that the 60 ns early arrival of the neutrino is due to failure of synchronization between the location`s clocks because of the motion of the satellite from west to east relative to the Earth frame of reference.
I think, if the satellite moves from the west to the east relative to the earth, the Earth should appear moving from the east to west relative to it. So when attempting to synchronize clocks by send 2 light signals from the satellite, the eastern end on the earth,which near Rome, should receive the signal before the western end, near Geneva. Therefore, the down-counting should begin in Rome before Geneva start to send the neutrino. That should lead to a apparent delay in the arrival of neutrino to Rome which is against the actual result, assuming the neutrino moves with speed of light c.

If one would like to make a sharp conclusion about the neutrino speed, they should send light photon through the same path using the same way of synchronization. So, if the light reaches Rome earlier by 60 ns, it would draw a doubt that the neutrino moves faster than light