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As per in the title. If it turns out that neutrinos do travel faster than the speed of light, how will the success of special relativity be explained? My apologies if this has been asked before; I've just browsed through few questions, and I couldn't find one that matches (although it was slightly touched on in one answer). Thanks.

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Essentially all "what if" ing is equivalent just now, and the answer is "we don't know, but it is going to be a lot of work". Really. I've sworn off closing these, but I suspect one of the other mods will do it. –  dmckee Sep 29 '11 at 2:23
It is closely related to the others, but I'm okay leaving this open since it asks the question in a slightly different (and more specific) way. The other questions are about the effects of FTL neutrinos, to which we responded that special relativity would have to be revised, whereas this one asks how it can be revised without clashing with all the experimental evidence that already supports the theory. But that's just one opinion. –  David Z Sep 29 '11 at 4:50
@David Zaslavsky. Thanks for leaving the question open. I learned a lot from the answers. –  Charmed Quark Oct 1 '11 at 2:00
Don't just thank me, thank everyone else who also didn't vote to close it. –  David Z Oct 1 '11 at 2:13
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3 Answers

up vote 8 down vote accepted

The various theoretical options are very different in nature, and the answer to this question almost defines the option.

1) Relativity is wrong, there is objective absolute time, Lorentz symmetry is emergent (as in electrodynamics before Einstein), and going faster than light doesn't create any time-loop paradoxes.

2) Relativity is valid, but neutrinos, not photons, travel at the actual relativistic speed-limit; photons have a small mass, or photons are confined to a braneworld while neutrinos can take shortcuts through hyperspace.

3) Relativity is valid, neutrinos are tachyons (or the OPERA result manifests some other sort of spacelike correlation), and something (Deutsch's multiverse, Hawking's CTC instability, weakness and/or uncontrollability of the effect, QM itself actually comes from CTCs...) prevents it from creating a time-loop paradox.

It should be extremely difficult to turn any of these 3 options into a fully working theory capable of reproducing the standard model. The odds are still heavily against OPERA having actually observed FTL neutrinos.

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Or maybe a new theory will be something that we never dream of. Like throwing out causality. And by the way, is it possible that CERN guys didn't take account of general relativity? –  C.R. Sep 30 '11 at 0:40
@Karsus The GPS system takes general relativity into account. I have given a wiki link in some other question/answer.en.wikipedia.org/wiki/… –  anna v Sep 30 '11 at 7:35
Thanks for the answer! –  Charmed Quark Oct 1 '11 at 1:57
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Let me rephrase your question:

If it turns out that light is really particulate how will the successes of Maxwell's equations be explained?

If you are a physicist you know the answer to this: by a quantum mechanical framework that incorporates Maxwell's equations.

The history of physics shows that whenever a data discrepancy to a widely accepted theoretical framework appears, the resolution of the paradoxes is in an expansion of the framework. The old data are consistent with the putative new theoretical framework by logical necessity: that is how the new framework is attained, by reconciling all data, conventional and new.

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Thanks for the answer. –  Charmed Quark Oct 1 '11 at 1:57
This seems very different, not a rephrasing. –  MBN Jan 9 '12 at 11:51
@MBN It is an analogy, I guess. –  anna v Jan 9 '12 at 12:28
I see. (9 more to go) –  MBN Jan 9 '12 at 13:02
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This paper by Feinberg has some interesting points about Tachyons stating that they might be compatible with Special Relativity and Quantum Field Theory. The essential points there are that Tachyons would have to be Spin-0 electrically neutral particles which despite the integer spin would obey a Fermi-Dirac statistic. I don't know if Spin 0 can somehow validly be attributed to Neutrinos, but another nice idea I read about (but sorry I forgot the source) was that the Neutrinos themselves are Tardions but some immediate Tachyons caused the FTL signal.

The basic explanation Feinberg's paper gives is that in QFT one cannot truly distinguish creation and annihilation events and therefore any apparent time-paradox would "simply" be a mixed up interpretation of these events.

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