Are Superluminal Neutrinos Possible?

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Are Superluminal Neutrinos Possible? Pions Don't Want to Decay Into Faster-Than-Light Neutrinos, Study Finds

"We've shown in this paper that if the neutrino that comes out of a pion decay were going faster than the speed of light, the pion lifetime would get longer, and the neutrino would carry a smaller fraction of the energy shared by the neutrino and the muon," Cowsik says.

"What's more," he says, "these difficulties would only increase as the pion energy increases.

"So we are saying that in the present framework of physics, superluminal neutrinos would be difficult to produce," Cowsik explains.

In addition, he says, there's an experimental check on this theoretical conclusion. The creation of neutrinos at CERN is duplicated naturally when cosmic rays hit Earth's atmosphere.

Some of the cosmic rays have far higher energies than what CERN can produce:

"IceCube has seen neutrinos with energies 10,000 times higher than those the OPERA experiment is creating," Cowsik says.."Thus, the energies of their parent pions should be correspondingly high. Simple calculations, based on the conservation of energy and momentum, dictate that the lifetimes of those pions should be too long for them ever to decay into superluminal neutrinos.

"But the observation of high-energy neutrinos by IceCube indicates that these high-energy pions do decay according to the standard ideas of physics, generating neutrinos whose speed approaches that of light but never exceeds it.

So, we still don't have a resolution to the faster than light results published last year, but this recent study points out some of the other effects that should be observed if neutrinos really are traveling faster than light, such as the lifetime and decay of pions, but these other effects which should be associated with faster than light neutrinos aren't being observed.

This suggests that if the neutrinos really are traveling faster than light, the rewrite of the laws of physics as we know them will have to be quite extensive.

On the other hand, it's entirely possible or even likely that there's a systematic error in the faster than light results that just hasn't been found yet.

So what is your prediction? Do you think the FTL result is valid and a major re-write of the laws of physics is in order?

Or do you think they probably have a systematic error and just haven't found it yet?

I'm in the latter camp myself, but that's by no means certain until this question is resolved.

There are some replication experiments taking place now, and the results should be announced later this year. Those should be interesting, and I'll be looking for them.

"So we are saying that in the present framework of physics, superluminal neutrinos would be difficult to produce," Cowsik explains.

That pretty much sums up my take of the OPERA experiment. "Difficult to produce" is code for "the math says this is impossible"

I'd put my money on an experimental error, but they won't figure out what happened. The theory is going to have to be proven wrong by other theoretical physics experiments and discoveries.

reply to post by Arbitrageur

Systematic error, almost certainly.

But wouldn't it be nice if it wasn't, and objects could move FTL after all.

And what a let-down if the only objects that could were... neutrinos.

I agree with the OP. Here's what I posted elsewhere that sums up my thoughts:

From talking to some folks in the field and from perusing sites like physicsforum.com, they all seem to think that it wouldn’t be a real big deal if the neutrinos do move faster than C. They claim the framework of Relativity will still be valid, but the constant c will no longer apply to light, but will still be a Universal speed limit. And, a search for an tiny and, as yet undetected, photon mass would begin, in order to confirm all this.

I am far from an expert, but I tend to disagree with this, for the following reasons.

Part of Einstein’s motivation to develop Special Relativity was the already Lorentz Invariant nature of Electromagnetism, as formulated under Maxwell’s Equations. In other words, Maxwell’s Equations were already compatible with SR, before SR was even invented. I think this is more than historically significant.

Within the EM wave equation is the velocity of the EM wave which is inversely proportional to the square root of the vacuum permeability times the vacuum permittivity – two properties of “free space”. This value, or velocity, happens to be the speed of light in a vacuum, or ~3*10^8 m/s.

Now, within Special Relativity, you can no longer think of time and space as separate entities. The mathematical quantity that “unites” them is called the metric. Within the metric is a constant which converts between time and space. That constant happens to be ~3*10^8 m/s! This ultimately shows nothing can move through spacetime faster than this speed, and it also helps preserve causality, as a result.

And, it seems to me, the fact that the speed of light (~3*10^8 m/s) pops up in both places, pretty much says it has to be light (or any massless particle) that moves at this speed, or Universal speed limit.

So, I think the neutrino result will be shown to be wrong too, but I’ve been accused of being brainwashed by Einstein more than once before, lol.

BTW, I forget which lab it was, but somebody already came back with negative results on this, confirming that neutrions were moving slower than c, for them.

I think there is something missing from this (so called) study. Actually, I think there are about 6 somethings missing from this study... the six extra hidden dimensions of our space-time.

"A 40-year-old puzzle of superstring theory solved by supercomputer"
www.abovetopsecret.com...

I see no mention in the OP's linked article, where the study ruled out the possible passage of the f-t-l neutrinos through an extra-dimensional shortcut through space-time.

Originally posted by EthanT
BTW, I forget which lab it was, but somebody already came back with negative results on this, confirming that neutrions were moving slower than c, for them.

I knew other studies were underway so I was expecting to see replication results...but I just haven't run across any yet.

If you can post a link about this I'd appreciate that very much.

Originally posted by Larryman

I see no mention in the OP's linked article, where the study ruled out the possible passage of the f-t-l neutrinos through an extra-dimensional shortcut through space-time.

You are repeating what is a fallacy. Travelling through (six) higher dimensions of space would not cut down the time of the neutrinos' journey through 4-d Minkowski space-time. In fact, it would merely lengthen the journey, as they would have to travel a short distance in hyperspace AS WELL AS the distance in ordinary space! There seems to be a fairly widespread conceptual error at work here in which the higher dimensions are confused with the notion of a wormhole, or Einstein-Rosen bridge between two regions of space-time, passage through which would cut down the time to travel between them. Hypothesizing wormholes in the compactified space predicted by superstring theory is NOT part of this theory and - as far as I know - no one has proposed this redundant hypothesis. If you move just through these higher dimensions, you are still standing still in the large-scale, 4-d Minkowski space-time and it is not going to shorten your time in travelling anyway in the latter. Proposing that neutrinos sometimes for some strange reason restrict their travel to higher dimensions therefore does not explain the experimental anomaly discovered at CERN. It is not that the idea is wrong - it simply does not even work.

reply to post by micpsi

Hypothesizing wormholes in the compactified space predicted by superstring theory is NOT part of this theory and - as far as I know - no one has proposed this redundant hypothesis.

I think an extra-dimensional shortcut for the f-t-l neutrinos has been proposed. I think I even read it mentioned on one of the ATS threads.

A simple "neutrino shortcut dimension" query of Google Search returns 860,000 results. Here is one...

"Neutrino Shortcuts in Spacetime"
arxiv.org...


adding: extra-dimensional neutrino ATS thread reference...
"An article - " 'Light-speed' neutrinos point to new physical reality"
www.abovetopsecret.com...

Neutrinos are very difficult to detect in the first place, so not detecting superluminal neutrinos in nature doesn't necessarily mean that they are not there. Nevertheless, the theoretical framework is strong enough that I, too, suspect a systematic error.

Originally posted by Astyanax
But wouldn't it be nice if it wasn't, and objects could move FTL after all.

Yeah but it's such a small amount over the speed of light, it seems like just a hair. Even if it was 150% the speed of light it would be more intriguing. But just 1% over the speed of light is all it takes to mess up a lot of theory.

And what a let-down if the only objects that could were... neutrinos.

No doubt neutrinos have some interesting properties in any case. I mean, most of them pass right through the entire planet Earth like it's not even there...how cool is that? But if your point is that FTL neutrinos going a hair over the speed of light don't imply that we'll be visiting the Andromeda galaxy anytime soon, I'd have to agree with that.

Originally posted by Larryman
A simple "neutrino shortcut dimension" query of Google Search returns 860,000 results. Here is one...

A search for [Elvis lives] returns over 2 million hits but I don't find the large number of results lends any more credibility to the claim.

"Neutrino Shortcuts in Spacetime"
arxiv.org...

Now that's the right way to support an idea, by linking to a paper, but I have no idea if that paper is peer reviewed, do you?

One thing I find interesting about that paper is the mention of a "curvature" which might be one way to explain the apparent speed being just a little over C, but still consistent. Any theory that explains the FTL results will have to deal with the fact that even the FTL neutrinos appear to have a speed limit, it's just a little higher than the speed of light, if the FTL observations prove to be true. The paper you linked to at least tries to explain that aspect of the observations.

Thanks for linking to that paper.

reply to post by Larryman


Consider a dot on a piece of paper. The dot is confined to the piece of paper, and, if it moves, can only move within the 2-dimensional plane of that paper. So, let's say there are two points on either side of the piece of paper - points A and B, 11 inches apart. The dot travels at 1 inch/second. That means, moving in a straight line, the dot takes 11 seconds to travel between point A and point B.

Now, what if the dot were suddenly able to move in the 3rd (up-down) dimension?
Let's say it took what someone calls a "shortcut" through this higher dimension. According to people claiming this sort of scenario for these superluminal neutrinos, the dot should be able to get from point A to point B faster than it could in 2 dimensions. So, let's see. What if the dot takes a semi-circular path from A to B? The length of this arc is going to be about 17.3 inches (11*pi/2). Still moving a 1 inch/second, it's now going to take the dot 17.3 seconds to travel the distance, as opposed to the original 11 seconds.

As you can see, the added dimension only makes the trip longer. This is true for any additional dimension(s). The shortest path between two points is a straight line. Adding dimensions only complicates that path, making it longer. If neutrinos had moved through extra dimensions, they would have been found to be travelling slower than predicted, not faster.

Originally posted by Arbitrageur

"Neutrino Shortcuts in Spacetime"
arxiv.org...

Now that's the right way to support an idea, by linking to a paper, but I have no idea if that paper is peer reviewed, do you?

They seem to be doing quite a bit of hoop-jumping... "if" this and "if" that. If spacetime is curved (that demands the physical reality of the mathematics of General Relativity, which I doubt)...if the bulk exists (personally, I find the idea silly, but that's me...I've never been a fan of watching supposedly intelligent people grasping at straws)...if neutrinos are able to travel through this extra dimension (I'm not sure why this would be the case, given the supposed purpose of the bulk). Of course, I only read the abstract, but that's what I got from it.

Now, to read the actual paper....

reply to post by CLPrime


Aside from my own personal bias, the paper seems pretty sound (do I count as a peer review? I doubt it, but a guy can dream, can't he?). My bias, of course, is against the fact that this is a matter of hindsight - it takes existing and vague experimental results and applies them to a rather broad and convoluted theory which depends on the existence of several questionable phenomenon (sterile neutrinos, brane curvature, and the existence of additional dimensions).

Here's the thing: what looks like a single theory is actually two very different mindsets.
First, you have the average person who doesn't understand higher dimensional physics. This person may even have a sort of metaphysical view of dimensions, which makes their view even further from our physical reality. This person hears of superluminal neutrinos and immediately thinks, "Well, these neutrinos are just taking a shortcut through extra dimensions." This is impossible, as I explained above.
Second, you have theoretical physicists who spend their lives forming the most complicated explanations for physical observations that we can imagine. These people have white boards full of nonsensical equations, symbols, and diagrams.
And then it happens... the average person, who has likely been ridiculed for what they believe, gets a hold of one of these complicated theories, and they feel vindicated. What they don't understand is that the work of theoretical physicists is not meant to vindicate the simplicity of the average person. The reality is, neither side has any real substance, and the apparent agreement between the two does nothing to support either. Both are just as pointless as each other.

Such is the case with this. The average person thinks superluminal neutrinos can be explained with extra dimensions. The theoretical physicist thinks they can be explained with a complicated mess of curved spaces, exotic particles, and large extra dimensions. Neither has any real chance of being right.

reply to post by Arbitrageur


I guess i'm in the FTL camp, i see no actual proof to negate the possibility.

According to Einstein FTL requires infinite energy and accrues infinite mass, yet we see Photons do not have infinite energy or mass, we see neutrinos approaching the speed of Photons yet they also do not have infinite energy or mass, clearly something is wrong here.

The only thing in the Universe that barely approaches infinite mass and energy is a black hole, yet they remain for arguments sake fairly static as they move together with the expanding space that surrounds them.

I have a feeling we are still at the tip of the iceberg.

My opinion is that until proved otherwise, anything is possible.

Cosmic..

reply to post by CLPrime

I certainly value your opinion. However I wouldn't go quite so far as to call it a peer review. But you make some good points.

What I find, is that when scientists dismiss a theory, they at least usually understand what it is they are dismissing.

When laypeople dismiss physics theories, it's far less common that they really understand what it is that they are even dismissing. The math is pretty hard for the average person to grasp, so that can make us feel kinda dumb.

But if we say "those scientists don't have all the answers" (and they don't), "and here's my theory", that makes us feel smarter and not so inadequate that we can't even understand the math the physicists use.

Regarding the possibility of neutrinos traveling in higher dimensions, I'm open minded to the possibility. Whether that could explain a measured superluminal velocity, I'm pretty skeptical about. Just because you can show a mathematical possibility of 25 dimensions, doesn't mean there are really 25 dimensions.

But that FTL neutrino extra-dimensional paper doesn't seem as outrageous as the peer-reviewed paper by Poplawski that says we are all living inside a black hole:

www.popsci.com...

I think he got pretty creative with his math. A little too creative, perhaps? I just don't find that idea too plausible even without doing a lot of math. It's off-topic but I posted it in reply to your point about some of the more esoteric science not necessarily being well-founded in reality, because it seems like an example of that.

Originally posted by Cosmic4life
I guess i'm in the FTL camp, i see no actual proof to negate the possibility.

Yes the paper in the OP doesn't qualify as proof, it just points out the inconsistencies with existing theory. But it stands to reason that if existing theory is wrong about FTL speeds, it may be wrong about other things too, so inconsistency with existing theory falls short of proof. However existing theory is based on a lot of other observations, so it won't be that easy to unravel.

According to Einstein FTL requires infinite energy and accrues infinite mass

Please forgive me for being slightly pedantic, but that's not really what Einstein claimed. Massive objects traveling AT light speed would have infinite mass. That's different than FTL or faster than light.

yet we see Photons do not have infinite energy or mass, we see neutrinos approaching the speed of Photons yet they also do not have infinite energy or mass, clearly something is wrong here.

It's not so clear to me that something is wrong. Photons are never at rest, so they don't have a rest mass, so they don't need to have an infinite mass to travel at the speed of light. So no problem with photons.

Neutrinos are a bit trickier. We aren't even 100% sure what the massess of neutrinos are, though we've placed some limits on the masses of various neutrinos. Whatever their mass actually is, it's pretty small, so even traveling at 99.999% the speed of light, their mass still won't be infinite. In fact, it won't even be very large.

Originally posted by Arbitrageur

I certainly value your opinion. However I wouldn't go quite so far as to call it a peer review.

Neither would I.

But that FTL neutrino extra-dimensional paper doesn't seem as outrageous as the peer-reviewed paper by Poplawski that says we are all living inside a black hole:

www.popsci.com...

I think he got pretty creative with his math. A little too creative, perhaps? I just don't find that idea too plausible even without doing a lot of math. It's off-topic but I posted it in reply to your point about some of the more esoteric science not necessarily being well-founded in reality, because it seems like an example of that.

Two years ago, I was working on my own universe-in-a-black-hole theory. My idea, at least, didn't pan out. While working on it, though, I do remember reading about Poplawski's work, and I tried to incorporate relevant parts into my own theory. It still didn't pan. Of Poplawski's work, itself, I'd feel comfortable comparing it with that of the neutrino paper. Both are highly speculative. Once you pass a certain level of theoretical, everything's about the same on the "nonsense" scale.

I think we need to follow a reasonable course with this superluminal neutrino result. First and foremost, the focus needs to be systematic error. Once that area has been exhausted, then we should start on the least complicated theories allowing superluminal neutrinos. If we do this, then curved 4-branes and higher dimensional bulk are pretty high up on the list of things to consider. The idea that simple extra dimensions are to blame doesn't even make the list, 'cause it's not a possible solution.

Originally posted by Cosmic4life

According to Einstein FTL requires infinite energy and accrues infinite mass, yet we see Photons do not have infinite energy or mass, we see neutrinos approaching the speed of Photons yet they also do not have infinite energy or mass, clearly something is wrong here.

Superluminal travel demands imaginary, not infinite, mass/energy. Luminal speeds require infinite energy. Infinite mass is only gained by objects with rest mass, but photons have no rest mass, so they don't accrue infinite mass. They do have relativistic mass, though, because they travel at the speed of light, which gives them momentum (actually, the other way around...they have momentum, which gives them apparent mass).

The only thing in the Universe that barely approaches infinite mass and energy is a black hole, yet they remain for arguments sake fairly static as they move together with the expanding space that surrounds them.

Black holes don't in any way, shape, or form approach infinite mass and energy. They have a mass equal to the mass of the object (usually a star) that collapsed to form them. What happens is this mass gets compressed to within a specific volume, creating a strong gravitational potential from which light can't escape. The mass of the black hole is still only the mass of the original star.