FTL Neutrinos?

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nsaspook

Joined Aug 27, 2009
7,330
http://news.sciencemag.org/sciencenow/2011/09/neutrinos-travel-faster-than-lig.html

No previous measurements obviously rule out the result, says Kostelecky, who has spent 25 years developing a theory, called the standard model extension, that accounts for all possible types of violations of special relativity in the context of particle physics. "If you had told me that there was a claim of faster-than-light electrons, I would be a lot more skeptical," he says. The possibilities for neutrinos are less constrained by previous measurements, he says.
Still, Kostelecky repeats the old adage: Extraordinary claims require extraordinary evidence. Even Ereditato says that one measurement does not extraordinary evidence make.
http://profmattstrassler.com/2011/09/20/supernovas-and-neutrinos/
 

mik3

Joined Feb 4, 2008
4,843
A very interesting observation but I am wondering how they measure the time and how they know the exact instance the neutrinos leave CERN.
 

someonesdad

Joined Jul 7, 2009
1,583
If someone can verify the results, it will indeed be a foundation-rocking discovery. Alas, there are only a few places in the world that can make such measurements.

No doubt the CERN scientists were very thorough in analyzing their results and probably involved lots of people and effort before publishing the results -- they know how the results go against canonical thinking. However, they wouldn't be doing good science by covering things up. From what I've read, they're asking for verification because they know how revolutionary it would be to have to reject or modify the axiom of the constancy of the speed of light.

If it can be verified, it will be one of those events that rocks physics every century or so. However, my guess is they've not analyzed the errors correctly and it will eventually be found to be as per the canonical thought. However, if it is verified, it will be very exciting -- it may be an indication that the neutrinos are e.g. taking a shortcut through an unseen dimension -- and that could be some needed experimental information for string theory.
 

Thread Starter

nsaspook

Joined Aug 27, 2009
7,330
If you look at what they are really saying it's not that they move faster than 'c' (the speed limit of a mass-less particle) it's that light travels a little slower than 'c' and a neutrino is a little closer to 'c' speed than light. This would mean that a photon has mass at rest but photons do gain mass as their energy is increased so it's possible at least in theory to have a black-hole made only of photons.
 

Thread Starter

nsaspook

Joined Aug 27, 2009
7,330
http://static.arxiv.org/pdf/1109.4897.pdf

Measurement of the neutrino velocity with the OPERA detector
in the CNGS beam
After reading this paper, it's not just a matter of photon mass and energy. What they are seeing breaks the rules of SR/GR as the results are faster than 'c' and the difference is not minor. The best counter to this so far is the supernova light/neutrino measurements.


But, I won't do this if I'm wrong.
http://twitter.com/#!/jimalkhalili/status/117160630527594496
 
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magnet18

Joined Dec 22, 2010
1,227
one theory was that the neutrino slipped into a different dimension for a little bit, allowing it to appear to go faster than light.
Which would still be awesome.

[EDIT]
Whoops, someonesdad already mentioned this :p
 
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Profchuck

Joined Oct 5, 2011
4
I have read through the paper very carefully and it appears that the researchers have been quite thorough and have seriously examined all of the potential sources of error. Clearly this must be verified independently.

If you grind through the math one possible explanation emerges (however, I seriously doubt it). If the detected neutrinos have small and negative mass the SR and GR equations work. Very strange and I suspect that something else is going on. If the results hold up then relativistic causality may need to be re-examined.
 

Profchuck

Joined Oct 5, 2011
4
This is to be expected. Even intergalactic space is not a perfect vacuum. A few hundred hydrogen atoms per cubic kilometer can introduce minute refraction and when you consider the distances involved between the solar system and the Magellanic clouds this refraction will introduce observable time dispersion to visible light photons. According to current theory neutrinos do not undergo time dispersion because the concept of refractive index does not apply to them. As a result visible light photons will travel at a velocity slightly less than c while, presumably, the neutrinos travel at c resulting in early neutrino arrival even if they and the photons started out at the same time. One of the objectives of the OPERA detector experiment was to infer the mass of the various flavors of neutrino. Again current theory holds that if neutrinos are truly mass-less they will propagate at c if they have a small but finite mass their propagation velocity will be correspondingly less than c. This is consistent with both special and general relativity. In an earlier post I observed that if you assume a small but finite negative mass the solution to the equations suggest a propagation velocity slightly greater than c. I don't think this is what is happening here but it is interesting that the solutions of the equations permit that.
 
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steveb

Joined Jul 3, 2008
2,436
When supernova SN 1987A was observed, neutrinos appeared to arrive three hours before the visible light.
Which clearly contradicts the CERN results since supernova photons would arrive many years delayed if neutrinos were FTL to the degree indicated.

This is really interesting because it means that in order for their result that FTL neutrinos exist to be true, they have to have done two of the most difficult things in physics, both at the same time. They, will have discovered a new particle (namely a new neutrino variation that behaves differently than stellar neutrinos), and will have disproved a major cornerstone of all existing physics theory (namely Lorentz invariance).

In other words, the laws of probability are working against them.

However, I think the end result will be useful either way, although on very difference scale levels. Either they have discovered new physics which will revolutionize all physics theory, or they have uncovered a flaw in the GPS system, or at least a flaw in the interpretation of the GPS data.
 
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Profchuck

Joined Oct 5, 2011
4
I agree with Steveb. The most likely explanation is a mundane one. As revealed in the OPERA paper these are very difficult measurements to make. The researchers have obviously taken great effort to identify and adjust for potential sources of error but there could still be hidden assumptions that are responsible for the findings. I would love for this to be the harbinger of new physics but we probably are not that lucky.
 

Thread Starter

nsaspook

Joined Aug 27, 2009
7,330
I'm hearing/reading the timing difference is starting to look like a GPS error with the rotation of the earth maybe being misfactored somewhere in the software/hardware timing chain, possibly in the embedded software in the GPS receivers.

http://www.phys.lsu.edu/mog/mog9/node9.html
The Sagnac effect has an important influence on the system. Since most GPS users are at rest or nearly so on earth's surface, it would be highly desirable to synchronize clocks in a rotating frame fixed to the earth (an Earth-Fixed, Earth-Centered Frame or ECEF Frame). However because the earth rotates, this is prevented by the Sagnac effect, which is large enough in the GPS to be significant. Inconsistencies occurring in synchronization processes conducted on the Earth's surface by using light signals, or with slowly moving portable clocks, are path-dependent and can be many dozens of nanoseconds, too large to tolerate in the GPS. Thus the Sagnac effect forces a different choice for synchronization convention. Also, the path of a signal in the ECEF is not "straight." In the GPS, synchronization is performed in the ECI frame; this solves the problem of path-dependent inconsistencies.
http://areeweb.polito.it/ricerca/relgrav/solciclos/ashby_d.pdf

Timing something (neutrinos) that is not moving on the same Inertial time frame as the GPS receivers or the satellites is way over my head.
 
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Profchuck

Joined Oct 5, 2011
4
Remember, GPS goes to great lengths to remove relativistic effects from the tracking process. Is this a good place to start looking for timing and distance errors?
 

Thread Starter

nsaspook

Joined Aug 27, 2009
7,330
Another paper about possible timing problems due loss of synchronization of the atomic clocks when they were moved.
http://xxx.lanl.gov/pdf/1109.6160v2

The method requires accurate knowledge of the distance base-line traveled by the neutrino along with detailed budget-ing of any delays affecting the electronic transmission of
timing signals at both ends of the baseline. The overall
time of flight is established by time stamping local ref-
erence clocks at both sites using a single, common view
GPS clock signal received separately at both sites. The
time difference between time stamped clock signals at ei-
ther end is calibrated using a second atomic clock trans-
ported between the two GPS receivers.
Or maybe it's something else (simple). http://arxiv.org/pdf/1110.0239v1

We propose a possible explanation of OPERA results without invoking
any violation of Lorentz invariance and without any experimental errors.
The observed apparent time shift could be entirely accounted for by a
small variation of the averaged interaction cross section, being itself due
to a variation of the energy spectrum. A mere 10 % variation is enough
to account for the observed value, a leading pulse being obtained by a
decreasing average cross section with time, i.e. for neutrinos, a decreasing
average energy with time, both in the leading edge and in the trailing
edge. A crucial prediction of this model would be that the time shift is
independent of the distance, but should depend on the pulse shape.
 
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BillO

Joined Nov 24, 2008
990
Sorry to be a buzz kill, but a FLT neutrino would travel into the past, not the future.

It's a hell of a thing to get your head around, but you can if you try.
 

steveb

Joined Jul 3, 2008
2,436
Sorry to be a buzz kill, but a FLT neutrino would travel into the past, not the future.

It's a hell of a thing to get your head around, but you can if you try.
:p I think the gist of it is that the neutrinos are not really FTL. So, just as the experiment put the arrival of neutrino's into the wrong time slot, the joke has the punch line in the wrong time slot.
 
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