CERN team claims measurement of neutrino speed >c

[ZapperZ]

ZapperZ,

This paper looks interresting, although it could also be considered as overly speculative!

Overly speculative? In PRL? Surely you're joking!

Zz.

 

[PAllen]

Overly speculative? In PRL? Surely you're joking!

Zz.

Yeah, and from Glashow: the intelligent critic of all TOEs.

 

[lalbatros]

Overly speculative? In PRL? Surely you're joking!

Zz.

Best jokes are based on reality!
Cerencov radiation from FTL neutrinos is anyway overly speculative.

If you look on arXiv, you will see that probably a large majority of the papers are theoretical speculations assuming FTLn are real.
This reveals, in my opinion, a terrible gap between theoreticians and experimentalists.
This was really a shock for me, much more than the FTLn claim itself.
If 1% of these speculations goes to PRL, I would not be surprised, would you?
I assume, of course, that the PRL is not about pure mathematics and that papers in the PRL are dealing will physics.

Remember that there are terribly simple arguments against the reliability of the FTLn OPERA claim.
As long as there are no answer, anything else that experimental work is speculation.

 

[ZapperZ]

There's a difference between overly speculative, versus "speculation" based on what is published in journals such as PRL. Theoretical papers often have predictions that do not have experimental verifications ... yet! That what spurs experimentalists to verify such a thing. Still, these things do not get onto PRL that easily, considering the scrutiny that is required to get into such a journal.

So no, *I* would never call them overly speculative, and they certainly do not fit into the PF Rules criteria of what we consider to be overly speculative.

Have we exhausted the discussion on the OPERA result that we are now diverting the topic of discussion to the nature of theoretical physics papers published in physics journals? If we have, then we can safely close this thread and move on with the rest of our lives.

Zz.

 

[D H]

If you did, read this (you can find a copy of the paper on ArXiv)

http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.107.181803

Zz.

Sans a title change and some editorial wordsmithing (e.g. "Thus we refute the superluminal interpretation of the OPERA result" → "This presents a significant challenge to the superluminal interpretation of the OPERA data") , this (http://arxiv.org/abs/1109.6562) appears to be the pre-release version of the article in question.

 

[lalbatros]

...
Have we exhausted the discussion on the OPERA result that we are now diverting the topic of discussion to the nature of theoretical physics papers published in physics journals? If we have, then we can safely close this thread and move on with the rest of our lives.

Zz.

I simply explained my preference for experimental analysis at this point in time.
This is not a diversion, quite the opposite.

Nevertheless, it would be good to explain the relevance of this paper (Pair Creation Constrains Superluminal Neutrino Propagation) to the OPERA claim, if there is one.
My understanding is that known physics can be extrapolated to the FTL domain and would predict something not seen on OPERA.

The OPERA result contradicts known physics on one point: FTL.
By combining this contradiction with any other part of known physics, extrapolated if necessary, one could probably built as many other contradictions as we would like.
That is in no way a discsussion of the OPERA claim.
One could just as well discuss a neutrino version of the grand father paradox.

In other words: experiments challenge theory, not the opposite.

 

[ZapperZ]

I simply explained my preference for experimental analysis at this point in time.
This is not a diversion, quite the opposite.

Nevertheless, it would be good to explain the relevance of this paper (Pair Creation Constrains Superluminal Neutrino Propagation) to the OPERA claim, if there is one.
My understanding is that known physics can be extrapolated to the FTL domain and would predict something not seen on OPERA.

The OPERA result contradicts known physics on one point: FTL.
By combining this contradiction with any other part of known physics, extrapolated if necessary, one could probably built as many other contradictions as we would like.
That is in no way a discsussion of the OPERA claim.
One could just as well discuss a neutrino version of the grand father paradox.

In other words: experiments challenge theory, not the opposite.

I have no idea what we are arguing about. If you had looked at my posts on here, I've always emphasized the test that MINOS and T2K about to embark. What do you think they are? Theoretical calculations? I also mentioned the most credible challenge to the OPERA result so far being from ICARUS. Again, what do you think that is?

Note that this all started because you said the following:

In addition to that, since neutrinos are not charged and interact very weakly, I do not see why they should emit Cherenkov radiations if they were FTL.
Once more, I do not see how such a conclusion could be based on current theories that exclude any FTL transmission.
I admit I must be lacking some background on this topic.

I pointed out the Cohen-Glashow paper as an example of a theoretical model that deduced the energy spectrum of such FTL neutrinos (if they exist). Since you ASKED, a response was given. If you disagree with it, then write a rebuttal to PRL.

Zz.

 

[lalbatros]

New Constraints on Neutrino Velocities
Authors: Andrew G. Cohen, Sheldon L. Glashow
(Submitted on 29 Sep 2011)

Abstract: The OPERA collaboration has claimed that muon neutrinos with mean energy of 17.5 GeV travel 730 km from CERN to the Gran Sasso at a speed exceeding that of light by about 7.5 km/s or 25 ppm. However, we show that such superluminal neutrinos would lose energy rapidly via the bremsstrahlung of electron-positron pairs ($\nu\rightarrow \nu+e^-+e^+$). For the claimed superluminal neutrino velocity and at the stated mean neutrino energy, we find that most of the neutrinos would have suffered several pair emissions en route, causing the beam to be depleted of higher energy neutrinos. Thus we refute the superluminal interpretation of the OPERA result. Furthermore, we appeal to Super-Kamiokande and IceCube data to establish strong new limits on the superluminal propagation of high-energy neutrinos.

ZapperZ,

I thank you for having provided me the reference, I aknowledge that it answered one of my question.

However, I was simply stressing that a theory cannot constrain an experimental result and can even less refute it.
We all know that if the FTLn were confirmed experimentally, it would shake the whole modern physics. I don't see why the theories used by Cohen and Glashow would be exceptions. Therefore, their argument is a tautology, and a tautology can't refute anything.

 

[ZapperZ]

ZapperZ,

I thank you for having provided me the reference, I aknowledge that it answered one of my question.

However, I was simply stressing that a theory cannot constrain an experimental result and can even less refute it.
We all know that if the FTLn were confirmed experimentally, it would shake the whole modern physics. I don't see why the theories used by Cohen and Glashow would be exceptions. Therefore, their argument is a tautology, and a tautology can't refute anything.

Then I look forward to your rebuttal in PRL.

I think this has been a total waste of my time.

Zz.

 

[PAllen]

I have to say I sympathize with lalbatros point of view on this. While it is interesting and useful to see what are the consequences of changing current theory in one respect (FTL neutrinos) while keeping core parts of existing theories, it seems quite an overstatement to call conclusions from that a refutation of an experiment. I greatly admire Glashow, and like that paper, but that one phrasing seems over the top to me. What we have in this paper is yet another reason to be skeptical of the OPERA claim, but hardly a refutation.

 

[John Hobson]

When you fire a bullet or a space rocket from the earth, they retain the angular momentum of the surface of the earth. Would this be true for a neutrino, or a photon? If true for a neutrino, with mass, but not for a photon, with no rest mass, then the neutrino would follow a curved path and the photon travel in a straight line. But in our rotating frame of reference it is actually the neutrino that would appear to travel in a straight line and the photon that would follow a curved path. To us the neutrino would be traveling a shorter distance than the photon. And so might arrive earlier. Any thoughts?

 

[TrickyDicky]

I have to say I sympathize with lalbatros point of view on this. While it is interesting and useful to see what are the consequences of changing current theory in one respect (FTL neutrinos) while keeping core parts of existing theories, it seems quite an overstatement to call conclusions from that a refutation of an experiment. I greatly admire Glashow, and like that paper, but that one phrasing seems over the top to me. What we have in this paper is yet another reason to be skeptical of the OPERA claim, but hardly a refutation.

This was brave of you!
I couldn't agree more.

 

[R32GTR]

Hum,

sorry to bring back this post.

I was just wondering, has there been any thought given about our whole universe
actually moving. I know it hard to imagine, since obviously we would have nothing to
compare this displacement with, but I can't really see why it couldn't be possible.

Could such a thing account for the difference in speed measured, and if it could what
would that speed need to be ?

 

[BertMorrien]

About "Measurement of the neutrino velocity with the OPERA detector in the CNGS beam"
( http://static.arxiv.org/pdf/1109.4897.pdf )
Somewhat late, but I had to think first..

In an experiment there is always a stimulus and a response.
Using a response for which there is no corresponding stimulus is invalid, because there was no experiment.
Using a stimulus for which there is no corresponding response is invalid as well, for the same reason.
The latter is the case in the current analysis of the OPERA Collaboration.

Only a part of the PEW contains start time information of the proton (stimulus) that later resulted in a neutrino detection (response).
The remaining parts or the PEW contain start time information of protons for which there was not a neutrino detection.
The current analysis allows the remaining parts to determine the shape of the PDF; it cannot be ruled out that this results in bias, because of the irrelevant start time information in the PEWs.

A number of physicists pointed out that these remaining parts are required for constructing the PDF to enable the maximum likelihood analysis and they dismissed the idea that this was invalid.
This seems the mainstream view and I am wondering what to think about that.
It explains why the analysis is taken for granted.

See also https://sites.google.com/site/bertmorrien/

Bert

 

[DevilsAvocado]

Hum, ... and if it could what would that speed need to be ?

Too fast to be measured and too slow to make any difference.

 

[petm1]

If the shape of a light cone's leading surface is flat and all of its motion is thru space with no rest mass so no change in time and a neutrino shape as spherical with rest mass that dilates in time proportional to its shape make this discrepancy the difference between the photon and the neutrino and not their speed?

 

[vpiter]

There is a problem.
I want to know.
The speed of the protons to the target?
The rate of mesons to produce a neutrino?

 

[lalbatros]

Only a minority of the arXiv papers concentrate on the real topic: the experimental aspect.
The last one is also quite interresting:

http://arxiv.org/ftp/arxiv/papers/1111/1111.3284.pdf

Clearly also, the truth can be established only by those people who own the complete files.

 

[tmfs10]

According to rumors, the new experiment (with short pulses) still shows a superluminal signal

http://motls.blogspot.com/2011/11/opera-neutrinos-ftl-even-at-3-ns.html

 

[Histspec]

Another paper concerning OPERA is now published in Physical Review D:
Altschul: "Consequences of neutrino Lorentz violation for leptonic meson decays"

http://prd.aps.org/abstract/PRD/v84/i9/e091902
http://arxiv.org/abs/1110.2123

 

[Deicider]

So FTL neutrinos confirmed after all, no error whatsoever.

So it seems measurement wasn't the issue after all.
I think its pretty obvious that there is a limit on speed, this is easily can be observed as particles gain mass as they approach light speed.

That leaves the possibility of us having a wrong measurement of light speed.

Also i know there are other threads about neutrinos but this is today's news that are confirming FTL neutrinos.
Link:
http://www.science20.com/quantum_diaries_survivor/opera_confirms_neutrinos_travel_faster_light-84763

 

[StevieTNZ]

http://www.scientificamerican.com/article.cfm?id=why-neutrinos-might-wimp-out

I don't see any news about FTL neutrinos on www.physorg.com, and I'd think they'd report it by now if there was any

 

[tmfs10]

Nature report on the new experiment

http://blogs.nature.com/news/2011/11/neutrino_experiment_affirms_fa.html

 

[Deicider]

http://www.scientificamerican.com/article.cfm?id=why-neutrinos-might-wimp-out

I don't see any news about FTL neutrinos on www.physorg.com, and I'd think they'd report it by now if there was any

http://www.guardian.co.uk/science/2011/nov/18/neutrinos-still-faster-than-light?newsfeed=true

 

[Pengwuino]

This is just showing that the same experiment got the same result. Confirmation this is not. Confirmation will need to come from a different group.

 

[Deicider]

This is just showing that the same experiment got the same result. Confirmation this is not. Confirmation will need to come from a different group.

But many different groups did the experiment and they all got the same results.

If there was an error don't you think the world scientific community would point it out?
I mean this took the scientists AND the public by surprise, so everyone is out to get the answer, don't you think if there was an 'error' people would found it already?

Obviously it has to do with very basic things, like the nature of neutrinos, or our understanding of light etc.

 

[Pengwuino]

But many different groups did the experiment and they all got the same results.

What? OPERA is just 1 experiment

In fact, OPERA contradicts other experiments and observations.

If there was an error don't you think the world scientific community would point it out?
I mean this took the scientists AND the public by surprise, so everyone is out to get the answer, don't you think if there was an 'error' people would found it already?

They have been pointing out things on a daily basis. With complex experiments such as this, it's not a matter of someone saying "Oh you didn't do this" and the group saying "oh, duh, thank you, problem resolved". People on the outside don't have access to the experiment and can only rely on what OPERA has reported. Beyond that, just because people propose solutions doesn't mean that they are the solutions either.

You need a different experiment to confirm.

 

[Vanadium 50]

This is the CERN statement:

OPERA experiment update 18 November 2011

Following the OPERA collaboration's presentation at CERN on 23 September, inviting scrutiny of their neutrino time-of-flight measurement from the broader particle physics community, the collaboration has rechecked many aspects of its analysis and taken into account valuable suggestions from a wide range of sources. One key test was to repeat the measurement with very short beam pulses from CERN. This allowed the extraction time of the protons that ultimately lead to the neutrino beam to be measured more precisely.

The beam sent from CERN consisted of pulses three nanoseconds long separated by up to 524 nanoseconds. Some 20 clean neutrino events were measured at the Gran Sasso Laboratory, and precisely associated with the pulse leaving CERN. This test confirms the accuracy of OPERA's timing measurement, ruling out one potential source of systematic error. The new measurements do not change the initial conclusion. Nevertheless, the observed anomaly in the neutrinos' time of flight from CERN to Gran Sasso still needs further scrutiny and independent measurement before it can be refuted or confirmed.

On 17 November, the collaboration submitted a paper on this measurement to the peer reviewed journal JHEP. http://arxiv.org/abs/1109.4897" .

 

[zahero_2007]

http://www.interactions.org/cms/?pid=1031226
I feel that the results of OPERA experiment are true

 

[PAllen]

Interestingly, the Nov. 17 version on arxiv gives no information about the new measurement in the PDF, and only one sentence in the non-pdf version of the abstract. Also, the JHEP journal reference isn't mentioned in the arxiv. I wonder if there will be further updates to the arxiv?