CERN team claims measurement of neutrino speed >c

[Saw]

You absolutely are making sense, IMHO. This is one of those things that have disturbed me quite a bit. Even Michio Kaku himself has spread these notions simultaneously.

I think the issue comes from the fact that FTL travel would violate the standard physical interpretation of the mathematics of SR, as opposed to the mathematics of SR in of itself. Thus, the "physics" of relativity would change if FTL travel was discovered, but that doesn't mean that much of the math goes away. Scientists would likely use the mathematics of Lorentz transformations (being the "convenient" mathematical tool that it is) even after discovering FTL travel, and thus, in response to such a discovery, they would grab onto the "fantastic" notion that backwards time travel is somehow validated, rather than to the idea that Lorentzian physics is violated, for the latter does not in an obvious way offer an "exciting" hope to inspire the imagination of adventurers.

I tend to agree with you. FLT is theoretically possible subject to most unlikely conditions. Causality is a logical must you cannot do without. However, probably this thread is more focused on finding the flaw in CERN experiment. The old one is contaminated with the LET issue. It may be more adequate to start a new one.

 

[TrickyDicky]

Causality is NOT necessarily violated by FTL travel.

This is obvious, that even people who are supposed to have a minimumm knowledge of relativity seem often confused about it suggests to me a FAQ devoted to clarify it might help.

 

[Dale]

I will concede though that, yes, you could say that Lorentz transforms, and not so much the idea of spacetime, is responsible for the notion that FTL travel implies causality violation.

That is close enough to agreement for me. I don't think that the "ala carte" part of the discussion is appropriate to this thread, so I will not pursue it here and will simply encourage you and gvk to do the same.

If you wish to continue that then I encourage you to start a new thread on the topic and I will participate.

 

[nsaspook]

Timing delay errors from fiber-optic cable visual.

I built a prototype device to detect bad fiber cables using time delay changes and made a few videos to check pulse delay calibration. These changes in time delays are from only moving the fiber a very small distance from the fully locked position. The display sync is locked on the send pulse on the left, the received (delayed) pulse is on the right.

http://flic.kr/p/bmmGau

 

[Galteeth]

Timing delay errors from fiber-optic cable visual.

I built a prototype device to detect bad fiber cables using time delay changes and made a few videos to check pulse delay calibration. These changes in time delays are from only moving the fiber a very small distance from the fully locked position. The display sync is locked on the send pulse on the left, the received (delayed) pulse is on the right.

http://flic.kr/p/bmmGau

http://news.sciencemag.org/scienceinsider/2012/02/official-word-on-superluminal-ne.html?ref=hp

 

[jambaugh]

I will concede though that, yes, you could say that Lorentz transforms, and not so much the idea of spacetime, is responsible for the notion that FTL travel implies causality violation.

That may be giving up too much. The "idea of space-time" invokes some form of relativity principle which via Lie group deformation and stability arguments leaves either SO(4) (euclidean relativity, we can rotate 360° and travel back in time) ISO(3) (Galilean relativity) or SO(3,1) (Einstein Special Relativity). The implications rule out all but SO(3,1) given a vast amount of observational data and mathematical realities. One might argue that the constant c is incorrect but too much empirically verified evidence depends on the given value.

[For reference see Segal's work on stability of Lie groups under deformation, I have no specific citation but he showed that all semi-simple Lie groups are stable under small perturbations of their algebraic structure (when constrained to still yield a Lie group)]

It all means that Minkowski space-time is on as solid a footing as Euclidean spatial geometry, and these may only be invalidated (without wholly abandoning unified space-time) in the same way, i.e. allowing for curvature in the respective spatial or space-time geometries, i.e. invoking a form of GR.

To abandon locally Lorentzian physics would require abandoning unified space-time all-together and consider some alternative theory with preferred frames and an absolute time... and of course describe a mechanism by which we seem to see Lorentzian physics e.g. Lorentz's original notion that an aether causes slowing of clocks and shrinking of objects.

In short...

In the name of Ockham's razor, I would give up "Lorentzian physics" before I give up causality.

is giving up on "space-time" all together. We would have to go back to the pre-Einstein aether or something similar.

This is why I'd give long odds that any claim to FTL signals is some combination of analytical or experimental error.

 

[jambaugh]

I think the issue comes from the fact that FTL travel would violate the standard physical interpretation of the mathematics of SR, as opposed to the mathematics of SR in of itself. Thus, the "physics" of relativity would change if FTL travel was discovered, but that doesn't mean that much of the math goes away.

No, you can't "tweak" SR. The "mathematics of SR in and of itself" would have to be abandoned. The mathematics of deformation of the algebra dictates that any variation of the group structure (which defines the value of c) is equivalent to a rescaling of the representation (change in t and x units). This has physical implications e.g. a gravitational field as you vary the group over space-time as in GR. If SR with the current c value is wrong it must be a.) drastically wrong and b.) there must be some additional mechanism making it appear right, and so c.) there's no reason to hold onto any relativity theory or unified space-time except aesthetic preference.

 

[GTOM]

I think the question is, can something be outside the boundaries of Lorentz transformations, or not?
Otherwise, i can rather accept LET than SR, since we learned, that space actually isn't empty, it is filled with "dark energy" (aether?).

 

[Dickfore]

There is now an official statement by OPERA:
http://www.nature.com/news/flaws-found-in-faster-than-light-neutrino-measurement-1.10099
And the press release update from February 23:
http://press.web.cern.ch/press/PressReleases/Releases2011/PR19.11E.html[/URL]

They say that there were actually [B]two[/B] possible sources of error (in opposite directions), which might significantly influence their former result. They will check it in May.[/QUOTE]

Yes, this press release is one day after the following news article from Science:

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

dated February 22, 2012

 

[cdux]

In layman's terms is the neutrino faster than light buried by the consensus?

 

[yuiop]

In layman's terms is the neutrino faster than light buried by the consensus?

Think so.

 

[Enoy]

ICARUS posted yesterday a paper where they show that neutrinos from cern to ICARUS was exactly at the light speed 299792,458 km/s :-(

http://arxiv.org/abs/1203.3433

If similar experiments, at OPERA and Fermilab later this year, finds the same result, that V-C = 0, it means that neutrinos that moves through the Earth can not move faster than light inside Earth (mass-densities). And in my opinion this means that aether-theory actually is finally falsified in an absolute way ! The reason for why I mean this, is that if there is an aether that light spreads through, this aether should have been "more thin / thinner" inside mass densities like the earth, and then massless particles / light-photons would have spread faster through this thinner aether inside Earth ! But now that (if) it is not true that speed limit is higher inside earth, this means that an aether can NOT be real !

 

[Ryan_m_b]

BBC reports slow neutrinos - http://www.bbc.co.uk/news/science-environment-17364682

 

[Dickfore]

Is someone still moderating this thread? I would appreciate if the mention of aether is purged out of this thread.

 

[PhilDSP]

Isn't the fact that a massive particle has been measured to travel at c slightly upsetting in itself?

 

[Dickfore]

It is. However, $(c - v)/c \equiv \epsilon \sim 10^{-5}$ is compatible with SR and the experimental uncertainty of all these experiments.

The energy of a particle traveling at this close speed to c is:
$$\begin{array}{l} \frac{E}{m \, c^2} = \gamma = \left ( 1 - \frac{v^2}{c^2} \right)^{-\frac{1}{2}} \\ = \left[ 1 - (1 - \epsilon)^2 \right]^{-\frac{1}{2}} \\ = \left[ 2 \epsilon \, \left( 1 - \frac{\epsilon}{2}\right) \right]^{-\frac{1}{2}} \\ \sim (2 \epsilon)^{-\frac{1}{2}} \, \left[1 + \frac{\epsilon}{4} + O(\epsilon^2) \right] \end{array}$$
Considering the rest energy of neutrinos is of the order of 0.1 eV, this means that the energy of these neutrinos would be of the order of:
$$\frac{0.1 \, \mathrm{eV}}{\sqrt{2 \times 10^{-5}}} \sim 20 eV$$
which is negligible. Even higher energies would bring the speed of neutrinos so close to c that the difference could not be detectable in any terrestrial experiment.

 

[gvk]

All right. Thank you, ICARUS.

 

[StevieTNZ]

This is in the news: http://www.physorg.com/news/2012-03-faster-than-light-particles-cross-check.html

 

[TrickyDicky]

ICARUS used a new measuring detector based on liquid argon time projection chambers, anybody knows why this way of measuring speed of neutrinos is better or more reliable than the one used by OPERA? or how this change in mesuring technique might affect the results?

 

[PAllen]

ICARUS used a new measuring detector based on liquid argon time projection chambers, anybody knows why this way of measuring speed of neutrinos is better or more reliable than the one used by OPERA? or how this change in mesuring technique might affect the results?

I assume the detector is irrelevant. Just a different group, re-doing the goedesy and timing independently; different time delays for cables etc.

 

[exponent137]

Mistake of measurement (4 and 9) was very large according to dissagreement (0.3).
δt = (0.3 ± 4.0stat ± 9.0syst)ns
Does this mean that both mistakes (stat and syst) are really much smaller if they would be more precisely determined?

 

[Orion1]

In a paper posted on the same website as the OPERA results, the ICARUS team says their findings "refute a superluminal (faster than light) interpretation of the OPERA result."

ICARUS did not detect any Cherenkov radiation.

"The result is compatible with the simultaneous arrival of all events with equal speed, the one of light." - ref. 2

Reference:
A search for the analogue to Cherenkov radiation by high energy neutrinos at superluminal speeds in ICARUS - ICARUS
http://arxiv.org/ftp/arxiv/papers/1203/1203.3433.pdf

 

[Vanadium 50]

It 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.

 

[exponent137]

Let us assume that we measure speed and energy of neutrinos in the opposite direction that pions and kaons fly toward the target.
Is it so possible to reduce some velocities of neutrinos so much, that difference v-c would be measured?

p.s. According to Fig 1 in the mentioned article, pions and kaons fly toward the target.

 

[lalbatros]

A few months were enough to cast serious doubts on the OPERA results.
The doubts originated from within the team itself.
The famous OPERA paper was of no use in this process.
One may then seriously question why this paper was published at all.
Was it too difficult to wait one more year?
After all, the main result will be that neutrinos propagates at the speed of light.
The headlines about FTL neutrinos will remain as a big mistake.

 

[gvk]

"One may then seriously question why this paper was published at all. Was it too difficult to wait one more year?"

Time is not a matter. It was the result of measurements during past 5 yrs, and as any team they should publish results regularly. The unusual thing they did not check equipments during this period of time. Any strange result should immediately draw their efforts to find faulty equipments. Their desire to make discovery was stronger.

 

[lalbatros]

As you said, gvk, they should have checked their equipment.
This is a question of taking what it needs to do these checks: mainly time.
There cannot be good arguments for deliberately publishing a wrong result.

It is really striking for me how much the OPERA team stressed the statistical errors of their measurement, when at the same time they completely neglected the systematic errors.
It has often been said that such a big team of experts could not make beginners mistakes.
Yet, this is exactly what they did:

- over-confidence in their equipment
- neglect of systematic errors
- blind confidence in an irrelevant statistical analysis​

There will probably be two things to be remembered from this story:

- neutrinos propagates at the speed of light
- do not trust anything, specially your equipment​

 

[OnlyMe]

In a paper posted on the same website as the OPERA results, the ICARUS team says their findings "refute a superluminal (faster than light) interpretation of the OPERA result."

ICARUS did not detect any Cherenkov radiation.

"The result is compatible with the simultaneous arrival of all events with equal speed, the one of light." - ref. 2

Reference:
A search for the analogue to Cherenkov radiation by high energy neutrinos at superluminal speeds in ICARUS - ICARUS
http://arxiv.org/ftp/arxiv/papers/1203/1203.3433.pdf

The issue involved here represents "null" results when looking for a proposed analogue Cherenkov radiation associated with FTL neutrinos. What I mean here is though the original paper by Glashow and Cohen has merit, it is a theoretical paper, with no confirmation. Until the theorized analogue Chenkov radiation has been experimentally confirmed any experiment that fails to detect it, represents a failure to detect it, not proof that it exists, does not exist or that neutrinos cannot exceed c.

The problem is, that to experimentally confirm the analogue radiation the FTL neutrinos must first be confirmed. FTL neutrinos remain questionable and likely will not be put to rest until later this year when additional experiments have been conducted at both CERN/OPERA/ICAUS(?) and MINOS. Even then a full examination may require more than a single season, unless the current systemic issue can be proven the origin of the original data and conclusions.

 

[Plebeian]

So the head of the Opera team resigned and now they are saying that Neutrinos travel at the speed of light. Don't Neutrinos have mass? If so how can they travel at the speed of light?

http://www.bbc.co.uk/news/science-environment-17560379

Sandro Centro, co-spokesman for the Icarus collaboration, said that he was not surprised by the result.

"In fact I was a little sceptical since the beginning," he told BBC News at the time.

"Now we are 100% sure that the speed of light is the speed of neutrinos."

 

[PAllen]

So the head of the Opera team resigned and now they are saying that Neutrinos travel at the speed of light. Don't Neutrinos have mass? If so how can they travel at the speed of light?

http://www.bbc.co.uk/news/science-environment-17560379

Sandro Centro, co-spokesman for the Icarus collaboration, said that he was not surprised by the result.

"In fact I was a little sceptical since the beginning," he told BBC News at the time.

"Now we are 100% sure that the speed of light is the speed of neutrinos."

Please read at least some prior posts. This has been explained at least a dozen times in this thread. See, most recently, #751.

 

[Creator]

There will probably be two things to be remembered from this story:

- neutrinos propagates at the speed of light
- do not trust anything, specially your equipment​

Yea; and one more thing :
-- erroneous news always propogates faster than reality. :)

...

 

[alexg]

Nothing in the Universe moves faster than rumor.

 

[Zarqon]

Nothing in the Universe moves faster than rumor.

which is not breaking FTL because rumors on average contain no real information ;)

 

[muhla]

Questions about Opera experiment results

Hello falks! Can anybody inform me about last Opera experiment results? More specifically:
-How much energy was spent to run the neutrinos at C? Because according to relativity it needs infinite energy.And two relative questions:1.Can a particle be entirely converted to energy? 2.Does energy always have a carrier particle? Thanks a lot.

 

[Whovian]

-How much energy was spent to run the neutrinos at C?

What do you mean? They can't go at c. Perhaps you mean extremely close to c? In which case one would use the relativistic formula for kinetic energy.

Can a particle be entirely converted to energy?

If it annihilates with its antiparticle, yes.

Does energy always have a carrier particle?

Do you mean that you're wondering if all energy manifests itself as the mass of a particle? I don't think so, due to Special Relativity, but I'm not exactly a reliable source for this sort of stuff, and the Higgs (if it turns out to be an existent particle) would complicate things.