CERN team claims measurement of neutrino speed >c

[San K]

Neutrinos don't travel at only one speed.

agreed, thanks. For a moment let's forget neutrinos.

Now if we increase the value of c by 730kms/60 nanoseconds in the relativistic equations what happens to the results/mathematical answers? Do they become more, or less, accurate?

or is the effect too small for us to verify experimentally?

 

[PAllen]

Various experiments show that the limiting velocity and mass/energy factor corresponds to light speed by much better precision than the OPERA discrepancy. Thus, replacing the value of c with the OPERA measurement will conflict with many other observations. If the OPERA result is true, theoretical fixes will be much more complex than this.

See especially :

# Guiragosian et al., Phys. Rev. Lett. 34 no. 6 (1975), pg 335.

Relative velocity measurements of 15 GeV electrons and gammas. No significant difference was observed within ~2 parts in 10^7. See also Brown et al.
# G.L. Greene et al.,“Test of special relativity by a determination of the Lorentz limiting velocity: Does E=mc2?” Physical Review D 44 (1991) R2216.

An analysis combining the results of several experiments gives the result that the Lorentz limiting velocity must be equal to the speed of light to within 12 parts per million.

Both of these have error bounds much smaller than the OPERA discrepancy.

From:

http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html#limiting_velocity

 

[San K]

Very informative. Thanks PAllen

 

[alexg]

Neutrino velocity and GPS corrections

According to this, the relativistic corrections for the GPS were done using the GPS satellite as the rest frame, instead of using the Cern Opera site as the rest frame. The difference in the timing is 60 nanoseconds, which is exactly the difference calculated by Opera.

http://www.technologyreview.com/blog/arxiv/27260/

My question is, I've never seen this refuted, yet I've never seen this accepted as the explanation for the 'superluminal' neutrinos.

Does anyone know more about this?

 

[bcrowell]

According to this, the relativistic corrections for the GPS were done using the GPS satellite as the rest frame, instead of using the Cern Opera site as the rest frame.[...]Does anyone know more about this?

Van Elburg is a physicist who wrote an incompetent paper. Technology Review is edited by someone who is not a physicist, and who therefore was apparently not competent to figure out that Van Elburg's paper was incorrect.

The error in the paper is simply that he didn't bother to learn anything about GPS or the coordinate systems it uses, and he then proceeded to write a paper about GPS. His assumptions about how GPS works are all wrong. GPS uses general relativity, and general relativity doesn't have global frames of reference at all, so GPS uses coordinate systems, not frames of reference. He seems to have assumed that GPS uses a frame of reference tied to a satellite, which isn't true.

 

[WaveHarmony]

I was reading a book recently in which it was stated that X-rays travel faster through material substances than through empty space. Could it be that the CERN experiment shows that neutrinos travel faster through rock than through empty space?

WaveHarmony

 

[GTOM]

Source?
I know you said speculation, but do researchers who believe in tachyons believe they come from supernovae

This was purely speculative as i said, i just found one instance, where neutrinos arrived shortly after the main stream.

http://en.wikipedia.org/wiki/SN_1987A

At 7:35 a.m. Universal time, Kamiokande II detected 11 antineutrinos, IMB 8 antineutrinos and Baksan 5 antineutrinos, in a burst lasting less than 13 seconds. Approximately three hours earlier, the Mont Blanc liquid scintillator detected a five-neutrino burst, but this is generally not believed to be associated with SN 1987A.[6]Well, I have found this one.

http://www.science20.com/alpha_meme..._ultra_superluminal_small_initial_jumps-84774

"The neutrinos do not travel with superluminal velocity all the way. They only ‘jump’ a small initial distance shorter than 20 meters, after which they settle back and travel as usual with speeds below that of the speed of light. "

 

[Aether]

I don't believe that follows, from the situation, as it stands. Cherenkov radiation is already observed for charged particles and only requires that they exceed the speed of light in a medium other than vacuum.

The Cohen-Glashow paper was projecting a similar effect for FTL neutrinos, even though they have no charge, interact only weakly with matter and are traveling thorugh solid rock and earth, where light may not pass.

The Cohen-Glashow paper predicts that electron-positron pairs will be produced if and when a neutrino exceeds the maximum attainable velocity of the electrons and/or positrons. Their analysis does not depend on the interaction of neutrinos with a medium, or on the speed of light in the medium; but rather on the maximum attainable velocity of electrons and/or positrons.

This has only been theorized. Not proven or confirmed. The ICARUS data essentially demonstrates a lack confirmation, of the predicted theoretical result.

I am not saying that the OPERA results have been proven or confirmed, or that the analysis in the Cohen-Glashow paper has been proven or confirmed. I am saying that if we assume that the OPERA results are valid, and that the ICARUS results are valid, and that the analysis within the Cohen-Glashow paper is mostly valid (except for the part where they assume that the maximum attainable velocity of electrons and/or positrons is c), then all of that would imply that the maximum attainable velocity of electrons and/or positrons must be greater than c. How else could you reconcile those three things?

Neutrinos are sufficiently different from electrons and other subatomic particles, that I am not sure much of what, may or may not be observed regrading neutrinos, could be applied directly to other particles.

The Cohen-Glashow paper predicts the rate of electron-positron pair production from FTL neutrinos as a function of the maximum attainable velocity of electrons and/or positrons. If we assume that the analysis within the Cohen-Glashow paper is mostly valid, and that the observations reported by the OPERA team are valid, and that the observations reported by the ICARUS team are valid, then something is implied regarding the maximum attainable velocity of electrons and/or positrons; namely that the maximum attainable velocity of electrons and/or positrons must be greater than c.

Do you disagree with my conclusion based on those three assumptions?

 

[OnlyMe]

Do you disagree with my conclusion based on those three assumptions?

Despite the credentials of the authors, I think the Cohen-Glashow paper is speculative.

The OPERA results will be re tested. They will be confirmed or some fault will be discovered.

If the OPERA results are confirmed the Cohen-Glashow predictions will probably get dusty. If not, someone may come up with an experiment to prove or disprove their predictions.

In either case I don't believe that FTL neutrinos would change anything about the velocity of light. That has been tested and retested and proven time and again.

My hunch and this is pure speculation.., is that if FTL neutrinos are confirmed, it may say more about the fine structure of space and inertia, and their interaction with the neutrino, than about the larger picture as seen from within QM and SR.

 

[PAllen]

Despite the credentials of the authors, I think the Cohen-Glashow paper is speculative.

The OPERA results will be re tested. They will be confirmed or some fault will be discovered.

If the OPERA results are confirmed the Cohen-Glashow predictions will probably get dusty. If not, someone may come up with an experiment to prove or disprove their predictions.

In either case I don't believe that FTL neutrinos would change anything about the velocity of light. That has been tested and retested and proven time and again.

My hunch and this is pure speculation.., is that if FTL neutrinos are confirmed, it may say more about the fine structure of space and inertia, and their interaction with the neutrino, than about the larger picture as seen from within QM and SR.

Independent of Cohen-Glashow, the OPERA results, if confirmed, require major changes to SR and QFT. The equivalence of lightspeed with maximum speed in accelerators, and with mass-energy conversion factor have been proven with much smaller error bounds than the OPERA result. The only way to accommodate OPERA consistent with these experiments and SR is for them to be tachyonic - except that is also excluded because we have proof that neutrinos much lower in energy than the OPERA ones were slower rather than much faster. Thus the whole structure of SR fails; with it goes all of QFT, which is based on SR being precisely true.

The idea of local fixes is delusional. If the results are confirmed, I am confident physicists will eventually arrive at some theory, but it will not be small tweaks to the existing framework. The most local fix I've seen is that neutrinos above some energy threshold break SR and QFT briefly, then settle back to following them. However, that fix smells like early, crude, solutions to light speed constancy experiments. The real way forward (if OPERA is true) will be radical and unforeseeable at this time.

 

[Aether]

In either case I don't believe that FTL neutrinos would change anything about the velocity of light. That has been tested and retested and proven time and again.

All velocity measurements are ultimately coordinate system dependent, and that includes those of light. Nevertheless, we aren't talking here about the velocity of light per se; we are talking about the velocities of neutrinos, electrons, and positrons. Specifically, we are talking about the maximum attainable velocity of electrons and/or positrons if and when they happen to be produced in-flight by FLT neutrinos.

The equivalence of lightspeed with maximum speed in accelerators, and with mass-energy conversion factor have been proven with much smaller error bounds than the OPERA result.

We do have much experience with particles that have been accelerated by exchanging photons between particles; and always the relative speed limit for accelerating one particle by an exchange of photons with another particle has been exactly the limiting velocity of the photons themselves. However, why should the maximum attainable velocity of electrons and/or positrons be equal to the velocity of photons if and when those electrons and/or positrons happen to be produced in-flight by FTL neutrinos?

Also, why should the maximum attainable velocity of electrons and/or positrons that happen to be produced in-flight by FTL neutrinos be limited to c relative to the earth-based lab where the FTL neutrinos either originated or terminated?

Take cosmic inflation for example, the maximum attainable relative velocity for any two particles is not strictly limited by the speed of light because the relative acceleration between all particles in the universe is not limited to what is attainable by an exchange of photons between the particles.

 

[PAllen]

All velocity measurements are ultimately coordinate system dependent, and that includes those of light. Nevertheless, we aren't talking here about the velocity of light per se; we are talking about the velocities of neutrinos, electrons, and positrons. Specifically, we are talking about the maximum attainable velocity of electrons and/or positrons if and when they happen to be produced in-flight by FLT neutrinos.

We do have much experience with particles that have been accelerated by exchanging photons between particles; and always the relative speed limit for accelerating one particle by an exchange of photons with another particle has been exactly the limiting velocity of the photons themselves. However, why should the maximum attainable velocity of electrons and/or positrons be equal to the velocity of photons if and when those electrons and/or positrons happen to be produced in-flight by FTL neutrinos?

Also, why should the maximum attainable velocity of electrons and/or positrons that happen to be produced in-flight by FTL neutrinos be limited to c relative to the earth-based lab where the FTL neutrinos either originated or terminated?

Take cosmic inflation for example, the maximum attainable relative velocity for any two particles is not strictly limited by the speed of light because the relative acceleration between all particles in the universe is not limited to what is attainable by an exchange of photons between the particles.

The point of this comment is that you can't get away with saying we were simply wrong about what value of c is used in SR formulas. c for mass energy conversion, c as the limiting velocity when KE for a particle is huge, and c as light speed, have all been shown to be the same to much less than the OPERA deviation. This means little fixes to SR and QFT won't work.

Recession velocity of galaxies is an irrelevant example because it is separation speed in one coordinate system (one particular foliation into simultaneity slices), analagous to the SR situation that if A travels left at .99c and B travels right at .99c, the separation speed is 1.98 c. Yet the speed of A from B's point of view is < c. Similarly, the speed of a receding galaxy from solar system frame in GR is either undefined (distant velocities have no unique definition in GR), or it is < c (you have to parallel transport one 4 velocity to the other; while this process is path dependent, you always get < c this way, and if you do the parallel transport along the light path, you get a relative speed consistent with local kinematic Doppler per SR).

 

[San K]

The point of this comment is that you can't get away with saying we were simply wrong about what value of c is used in SR formulas. c for mass energy conversion, c as the limiting velocity when KE for a particle is huge, and c as light speed, have all been shown to be the same to much less than the OPERA deviation. This means little fixes to SR and QFT won't work.

Recession velocity of galaxies is an irrelevant example because it is separation speed in one coordinate system (one particular foliation into simultaneity slices), analagous to the SR situation that if A travels left at .99c and B travels right at .99c, the separation speed is 1.98 c. Yet the speed of A from B's point of view is < c. Similarly, the speed of a receding galaxy from solar system frame in GR is either undefined (distant velocities have no unique definition in GR), or it is < c (you have to parallel transport one 4 velocity to the other; while this process is path dependent, you always get < c this way, and if you do the parallel transport along the light path, you get a relative speed consistent with local kinematic Doppler per SR).

agreed, good point.

in the CERN experiments the neutrino is running alone (against time/clock, not against a photon).

(side question: Is it because photon cannot travel through obstacles/earth? and finding/creating 730 kms of straight line free space is not easy? and generating muon neutrinos is not easy)

is there a way to have a (730 kms) race between photon and neutrino in space/vacuum ? in that case no clocks, no adjustments (for frames of references etc) would be needed.

 

[Drakkith]

San_K, I'm not sure a "race" against a photon would be possible. Neutrinos are so difficult to detect that you must produce a huge amount of them before you can even detect one. So I don't think you could have a race because you have no way of knowing if you are going to detect a specific neutrino that's racing a photon.

 

[Aether]

The point of this comment is that you can't get away with saying we were simply wrong about what value of c is used in SR formulas. c for mass energy conversion, c as the limiting velocity when KE for a particle is huge, and c as light speed, have all been shown to be the same to much less than the OPERA deviation. This means little fixes to SR and QFT won't work.

Little fixes to SR and QFT can’t account for gravity either. If (big if) neutrinos can travel FTL, then they probably weren’t boosted there by EM force alone.

Recession velocity of galaxies is an irrelevant example because it is separation speed in one coordinate system (one particular foliation into simultaneity slices), analagous to the SR situation that if A travels left at .99c and B travels right at .99c, the separation speed is 1.98 c. Yet the speed of A from B's point of view is < c. Similarly, the speed of a receding galaxy from solar system frame in GR is either undefined (distant velocities have no unique definition in GR), or it is < c (you have to parallel transport one 4 velocity to the other; while this process is path dependent, you always get < c this way, and if you do the parallel transport along the light path, you get a relative speed consistent with local kinematic Doppler per SR).

When we integrate Friedmann’s equation with cold dark matter and dark energy, using the standard LCDM model, we get a space with a radius (\tau) of about 45 billion light years that has evolved from zero radius in only about 13.7 billion years. If we were to parallel transport one 4 velocity from the big bang all the way to the edge of this space, would we get a different average velocity, something < c?

 

[PAllen]

When we integrate Friedmann’s equation with cold dark matter and dark energy, using the standard LCDM model, we get a space with a radius (\tau) of about 45 billion light years that has evolved from zero radius in only about 13.7 billion years. If we were to parallel transport one 4 velocity from the big bang all the way to the edge of this space, would we get a different average velocity, something < c?

Absolutely.

 

[mal4mac]

Farmelo's biography of Dirac gives an interesting account of Dirac writing a paper giving theoretical backing to the idea that energy is not conserved in certain particle reactions, based on experimental results from a top American experimentalist. Bohr "kind of" approved of the paper because he had speculated on such possibilities a decade earlier. The "German opposition" used this as an excuse to attack Dirac -saying the experiment was faulty and his ideas were c**p. Unfortunately for Dirac, they were right! He never speculated again based on one, or a few, sets of experimental results! So, I suggest, this thread is entirely a waste of time - wait a few years until several experimental teams have found the same results (or, as is likely, not!)

 

[Enoy]

Overview over papers dealing with neutrinos possible faster than light ?

Hello from Norway :)

Our physics teacher has given us in homework to write how physicists have reacted to and interpreted the results of the OPERA where they measured that neutrinos moved faster than the speed of light.

In this regard, I searced the internet and found lots of stuff by both relevant and irrelevant character. But I found one page that seems to contain most of the papers dealing with the OPERA neutrino speed measuremant:

http://web.mit.edu/redingtn/www/netadv/XftlNu.html

Is this a serious site to use as a reference in my homework ?

Sincerely
me :-)

 

[OnlyMe]

Hello from Norway :)

Our physics teacher has given us in homework to write how physicists have reacted to and interpreted the results of the OPERA where they measured that neutrinos moved faster than the speed of light.

In this regard, I searced the internet and found lots of stuff by both relevant and irrelevant character. But I found one page that seems to contain most of the papers dealing with the OPERA neutrino speed measuremant:

http://web.mit.edu/redingtn/www/netadv/XftlNu.html

Is this a serious site to use as a reference in my homework ?

Sincerely
me :-)

This is a Massachusetts Institute of Technology site, a respected university. I did not check all of the links but those I did check are all reputable sources, of information.

 

[sshai45]

Testing the "faster-than-light" neutrino claim.

Hi.

I was wondering about this. Could it be possible to test the "faster-than-light neutrino" claim by re-running the experiment with a lower-energy neutrino? Like if it were to be re-run with the energy reduced to the levels expected from a supernova explosion, at which it is known there is no significant deviation from light speed due to astronomical measurements? As then, if the experiment still showed the same "faster-than-light" speed, then it would strongly suggest experimental error as the cause since such would be inconsistent with the aforementioned astronomical observations (e.g. the supernova 1987A result).

 

[tmfs10]

Hi.

I was wondering about this. Could it be possible to test the "faster-than-light neutrino" claim by re-running the experiment with a lower-energy neutrino? Like if it were to be re-run with the energy reduced to the levels expected from a supernova explosion, at which it is known there is no significant deviation from light speed due to astronomical measurements? As then, if the experiment still showed the same "faster-than-light" speed, then it would strongly suggest experimental error as the cause since such would be inconsistent with the aforementioned astronomical observations (e.g. the supernova 1987A result).

Extremely hard to produce neutrinos with such low energies (in MeV as was in 1987A) AFAIK. There have been suggestions to test the energy dependence though. See end of this article by Matt Strassler.

 

[Histspec]

It seems that a simple explanation of this result has been found – no superluminal neutrinos, but only a bad connection between GPS and a Computer.

http://news.sciencemag.org/scienceinsider/2012/02/breaking-news-error-undoes-faster.html

"A bad connection between a GPS unit and a computer may be to blame...According to sources familiar with the experiment, the 60 nanoseconds discrepancy appears to come from a bad connection between a fiber optic cable that connects to the GPS receiver used to correct the timing of the neutrinos' flight and an electronic card in a computer. After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed. Since this time is subtracted from the overall time of flight, it appears to explain the early arrival of the neutrinos. New data, however, will be needed to confirm this hypothesis."

 

[TrickyDicky]

It seems that a simple explanation of this result has been found – no superluminal neutrinos, but only a bad connection between GPS and a Computer.

http://news.sciencemag.org/scienceinsider/2012/02/breaking-news-error-undoes-faster.html

They've got to be kidding. Well, if it turns out this is the case I wouldn't want to be in the Opera team, the laughs are going to be pretty loud.

 

[Drakkith]

It seems that a simple explanation of this result has been found – no superluminal neutrinos, but only a bad connection between GPS and a Computer.

http://news.sciencemag.org/scienceinsider/2012/02/breaking-news-error-undoes-faster.html

Wooo! Looks like they found the problem! No more Einstein is wrong posts!

 

[kikokoko]

one word to describe this story:
embarrassing

 

[Drakkith]

one word to describe this story:
embarrassing

These things happen. Especially with horrendously complex machines like the LHC and other particle accelerators that they use. I personally was expecting something like this to be the culprit. Though that isn't saying much I suppose.

 

[MartinJH]

one word to describe this story:
embarrassing

But inevitable?

 

[CaptFirePanda]

They needed to get the news out there in the event that they were right. CERN was very cautious in making any claims to the validity and expressed that confirmation was key in order for them to come to any absolute conclusions. There is nothing embarassing about this as it is how Science functions.

 

[Drakkith]

But inevitable?

Mistakes in general are inevitable. But there's no way to tell where they will crop up.
Luckily CERN was adamante in saying they needed confirmation.

 

[kikokoko]

the embarrassment is not about the science discovery path
(often involving trial-error procedures)

The HUGE problem was the hurry on the claim:
why do these guys announced amazing results,
before to accurately check instruments (timing, GPS, cabling, and so on)?