Of Particular Significance

This Time, ICARUS Really DOES Refute OPERA

POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON 03/16/2012

Well, ICARUS flies even higher, and so far shows no sign of losing its wings.

Remember OPERA, the experiment that claimed neutrinos sent from the CERN lab in Switzerland to the Gran Sasso lab in Italy arrive earlier than they were expected to? And that a couple of weeks ago had to admit they’d found a couple of problems that were large enough to scrap their result for the moment, and that require additional investigation?

And remember ICARUS, OPERA’s neighbor in the same Gran Sasso lab in Italy, which measured the energies of neutrinos from the CERN neutrino beam, and showed they were not altered in flight? And thus proved that if the neutrinos really were traveling faster than light, they did not exhibit anything like the variant of Cerenkov radiation that was suggested by and calculated by Cohen and Glashow?

Now, ICARUS’s result from the fall didn’t directly refute the OPERA experiment (despite some claims, even by them) but it certainly added to the aura of extreme implausibility that surrounded the whole story.

Well, this time ICARUS refutes OPERA. Essentially, they did the same measurement as OPERA-2, as I called the short-pulse variant of OPERA’s original experiment.  They took data at the same time as OPERA-2, in the same neutrino beam, in the same laboratory.  It took them a while to do all the distance and timing calibrations that OPERA had done many months ago, but they’re finished now. And whereas OPERA-2 gets the same result as OPERA-1— an early arrival of 60 nanoseconds (billionths of a second) — ICARUS finds a result consistent with an on-time arrival. Same measurement, different answer. At least one experiment made a mistake; and one result is vastly more plausible than the other, so I think the consensus is pretty clear in the matter.

ICARUS's 7 neutrinos (dark blue histogram), measured in October and November, arrived as expected to within 10 nanoseconds (billionths of a second). OPERA's result (but not its neutrinos) is shown at right, at approximately 58 nanoseconds early arrival.

In particular, ICARUS measured the arrival of 7 neutrinos while OPERA-2 was busy measuring 20 (as described in section 9 of their preprint). They find these neutrinos arrived on average on time, with an uncertainty of about 10 nanoseconds. This puts their result at least 4 standard deviations (or “sigmas”) away from OPERA’s result, even if you treat the errors very conservatively. It’s a clear, statistically significant disagreement between the two experiments.

The data on the neutrinos from OPERA-2, done simultaneously with but clearly disagreeing with ICARUS's result.

This is the way it works in science all the time. A first experiment makes a claim that they see a striking and surprising effect. A second experiment tries to verify the effect and instead shows no sign of it. It’s commonplace. Research at the forefront of knowledge is much more difficult than people often realize, and mistakes and flukes happen on a regular basis. When something like this happens, physicists shrug and move on, unruffled and unsurprised.

The only thing that makes this story unusual is that this particular (non-)effect was at the heart of one of the most famous statements of twentieth century physics — the universal speed limit suggested in Einstein’s historic 1905 paper — and so it hit the headlines in a big way. Otherwise, it was just like many other examples I’ve seen in my career.

By the way, if you insist on calling OPERA a “CERN experiment”, which is at best misleading and at worst completely wrong, you’d better call ICARUS a “CERN experiment” too. Same beam, same neutrinos, same accelerator team. And in fact there are a couple of people from CERN who signed the ICARUS paper. CERN’s reputation should not suffer for OPERA’s errors.

So ICARUS’s result likely brings us to the final aria of this OPERA, and I think it is finally fair to alert the stage manager to prepare to lower the curtain. Oh, there’s a tad more minor drama yet; OPERA needs to clarify whether the suspected causes of their 60 nanosecond time shift are the real causes, or if there are yet others; a rerun of the experiment by ICARUS and OPERA and maybe others is perhaps still justified, to get a clean result that will allow the community to put this whole story into the filing cabinet and lock it shut. But basically, barring a big mistake by ICARUS, it’s over.

The silver lining? The experimental particle physics community has learned how to make long-range distance and timing measurements that are more precise and more accurate than were ever possible before. Don’t be surprised if this knowledge turns out to be useful, in some unexpected way, in future experiments.

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  6. In the case of the latest ICARUS results, shouldn’t one consider that the data set is extremely small. The ICARUS group measured the speed of only seven neutrinos; which is too small a sample to lend itself to statistical analysis or to have any statistical relevance. More importantly since each neutrino of the seven neutrinos can be unequivocally associated with the proton bunch that produced them, should each measurement be taken as that of the speed of one particular neutrino? Also, wouldn’t be possible that within the accuracy permitted by the margins of error, the ICARUS measured the actual speed of seven individual neutrinos which differed by as much as 37ns?
    Since the sample size is too small to be statistically relevant, wouldn’t it be valid to consider that the recent ICARUS data tells us that 3 neutrinos travelled at relative speed below c, 1 travelled at c and 3 neutrinos travelled at speeds exceeding c?

    1. The statistics you question is accounted for in the ICARUS measurement, and your statement that the sample size is too small is not correct. 7 uncorrelated events with the uncertainties-per-event that ICARUS claims they can attain is indeed enough to give the uncertainties-on-the-average-of-7-events that they claim, and that puts them 4 standard deviations from OPERA, and agreeing with Einstein’s prediction to within about 15 nanoseconds.

      Remember that although each neutrino has its own speed, Einstein’s equations predict that neutrinos at these energies (more than 1 billion electron volts) and with these masses (less than 1 electron volt) have speeds that differ from the speed of light by less than one part in a trillion trillion. In short, the differences in their speeds should be completely irrelevant, according to Einstein. ICARUS’s result is consistent with this, but their measurements are only accurate to one part in a hundred thousand. Therefore it is no surprise that the neutrinos were measured to arrive with travel times that differ at a about a part in a hundred thousand; it is exactly what you would expect, given the imperfections in the measurements, if the neutrinos all traveled unmeasurably close to the speed of light.

      ICARUS will get more precise measurements once they have more events, but 7 was enough to refute OPERA.

  7. Yesterday, there was a seminar at LNGS on neutrino velocity measurements by OPERA, LVD, ICARUS, and Borexino.


    Some information on this was given in the Italian media. INFN president Ferroni said in an interview, that they actually confirmed the connector mistake by comparing data from cosmic muon neutrinos from 2007 and 2008, with data taken from 2009-2011.

    (Based on GoogleTranslation, I’m not a native Italian speaker)

    Q: President Ferroni, was the workshop at Gran Sasso useful, where neutrino measurements were announced, made ​​by the experiments of OPERA and LVD?

    A: So useful. With these new results we’re almost approaching to confirm that the measurement was caused by a malfunction of the fiber optic equipment.

    Q: How do you get the confirmation of the refutation this time?

    A: This time, not neutrinos from CERN were measured, but from cosmic muons. Consider that every five years, they can get about 300 muon neutrinos from the cosmos at Gran Sasso. The laboratories were created under the rock just to shield them from cosmic neutrinos.

    Q: And what did you see?

    A: That the measurement has been a certain value in 2007 and 2008, then the value has changed between 2008 and December 2011, when the value came back to that 2007. The difference between these two numbers is compatible with the value of Opera for the speed of the neutrino. Basically, it is confirmed that there was an anomaly in the project work. So that was the penultimate step towards the solution of the problem.

    Q: Why is the difference compatible?

    A: Because the disparity between the two values ​​of 2007 and 2008 is due to the same anomaly, signalled in the fiber optic connector. Probably this was a bad connector on one day in 2008 and remained so until this year, when it went to check.

    Q: In short, when will the final verdict arrive?

    A: You just have to wait when the neutrino beam from Cern is there again, between April and May. At that point all four experiments of the Gran Sasso – Opera, LVD, ICARUS, Borexino – will be ready to take the data and interpret them for the final word.

    Q: A prediction?

    A: Again, we are moving forward with great strides toward confirming that there was a mistake.

    1. Thank you. I guess we have to figure out what the thing whose “value” is described as having changed is. I’m not sure how you do timing with neutrinos from cosmic rays; naively you would have no idea when they would arrive, so I guess there must be some sort of consistency check internal to OPERA. Let me know if you learn more.

      1. They seem to have compared the cosmic neutrino (to coin a word) detections across OPERA and the nearby LVD. The offset seemed to shift by 60 nsec from 2008 until 2011, and then go back to the 2007 value in Dec 2011 when the connector was firmly plugged back in. So one should expect nearby detectors to detect atmospheric neutrinos at around the same time? Do they come in batches?

        1. That can’t be quite right…

          Maybe the trick is the following: cosmic rays produce neutrinos, then one of those neutrinos hits the rock near LVD or OPERA and produces a muon, then that muon passes through both LVD and OPERA and the timing of that muon’s passage is compared…?

          Or maybe one just uses the rare muons from cosmic rays that make it that far underground…?

          Trying to get more info…

  8. Professor Matt when you get a chance could you answer my second question? I was doing a very simple thought experiment about the big bang and thought that two objects could be moving away from each other at speeds greater than 51% the speed of light after the “Bang”. Observations from the center would never have them going faster than c away for the center. But wouldn’t an Observer from the mass moving in the opposite direction observe the other mass moving at speeds greater than c? Since the mass would be traveling at a constant velocity and there are “no physical experiment (mechanical, electromagnetic, optical—or any physical law whatsoever) that can distinguish between a state of absolute rest and a state of constant velocity.” Relativity would state all laws of physics should be the same for both observers. But wouldn’t they actually be traveling away from each other at greater than c? If this is not true are we not saying that there is one Galilean Space time instead of multiple Minkowski’s 4d versions of space time. I am not arguing the speed of light just that Physical Laws are dependent on the inertial observers frame. I really appreciate your patience with me.

    1. Just answered it for special relativity in the comment just above this one.

      For the Big Bang, it is even more complicated. But I’m a bit tired out and have to get back to work. Clearly this site needs a relativity section!

  9. Sorry to bother you but you have a great way of speaking down to my level. I still have one question about how Minkowski World lines fit into this. If two observers on two separate World lines were moving in opposite directions from one another at velocities greater than 51% the speed of light. Would either observer notice the other moving at a velocity greater than the speed of light away from them?

    1. Minkowski is predicated on a “natural” coincidence of points. Just ignore Minkowski.

      1. Thanks for the reply but that kind of throws me for a loop. I thought relativity was based on the idea of World Lines and inertial observations. Does this mean that you do not agree at all with relativity? I was thinking if it was wrong it needed only tweaking. If you could give me more of a layman’s response I would really appreciate it. I know you and the Professor have no problem conversing at the level you do. I just am really interested in this and would love to know all sides of the argument.

        Best Rick

        1. That’s simple. Minkowksi is simply an expression of spacetime. However, spacetime is the “natural” coincidence of points M and M’ as discussed by Einstein. Here is the quote again:

          “Are two events (e.g. the two strokes of lightning A and B) which are simultaneous with reference to the railway embankment also simultaneous relatively to the train? We shall show directly that the answer must be in the negative. When we say that the lightning strokes A and B are simultaneous with respect to be embankment, we mean: the rays of light emitted at the places A and B, where the lightning occurs, meet each other at the mid-point M of the length AB of the embankment. But the events A and B also correspond to positions A and B on the train. Let M΄ be the mid-point of the distance AB on the traveling train. Just when the flashes (as judged from the embankment) of lightning occur, this point M΄ naturally coincides with the point M but it moves…with the velocity…of the train.”

          If you look at the accompanying illustration, you will see that even though Einstein says that the illustration shows the “natural” coincidence of points M and M’, they do not coincide. Matt and Feynam, attempting to overcome this discrepancy by discussing M and M’ in terms of “very close,” misconceive the issue. Why? Because they can’t believe Einstein was dumb enough not to say whether two points coincide or not (and remember, Einstein in this book prefaces his remarks by maintaining his fidelity to Euclid). Instead, both points are a “little bit pregnant” with each other. Ha ha!

          But Einstein’s dumbness is not the issue, either. The real issue is, did Einstein do exactly what he set out to do? Of course he did. He simply did not believe in logical content or internal consistency. It’s BECAUSE other physicists DO demand logical content and internal consistency and COULDN’T locate the logical problem in the relativity of simultaneity (because they really didn’t understand constructivism or believe that Einstein would ever sign off on such nonsense) that they went off on this ad hominem comment about the “closeness” of Euclidean points.

          With all the renormalization nonsense in contemporary physics–endless prevarications which have made physics the joke of the intellectual world–you would think physicists would conclude, “Gee, maybe we should revisit SETTLED QUESTIONS.”

          Nope, much too vain and careerist for that. Sad–sick too.

    2. Ignore Mr. Ryskamp. He knows lots of fine words; he knows how to argue about Einstein’s words, and focus on how Einstein words things; he clearly knows nothing about the equations and confirming experiments that are the reasons we believe those words. And Mr Ryskamp’s explanations make no sense, which is why you are so confused. I’ll bet he even has a GPS device, but still doesn’t believe Einstein’s equations.

      If what Mr. Ryskamp said were true, the Large Hadron Collider simply wouldn’t work, because it was designed and built by people who used Einstein’s equations as a guide. The same is true of the world’s other particle colliders and particle beams, and even the GPS system. It is ridiculous to suggest that the reason Einstein is so popular is political; Einstein’s equations are popular because you can use them to build technology that WORKS — technology that makes money, and technology that solves problem, and technology that wins wars. Let Mr. Ryskamp go out and try to convince the Department of Defense that Einstein is wrong and their entire GPS system is a big waste of money.

      As for your question: The problem is that you are assuming that speeds add simply. Obviously, if they did, there would be a logical contradiction, for the reason you raised. But in Einstein’s theory, and in experiments that test that theory, they don’t.

      One teaches this to students the first time they learn about relativity.

      At the LHC, protons traveling at nearly the speed of light (relative to us) collide with protons traveling at nearly the speed of light (relative to us) in the opposite direction. Isn’t it obvious that they are traveling at twice the speed of light relative to each other?

      Almost obvious. The subtlety is the following: What Einstein’s equations say is that FROM THE POINT OF VIEW OF EITHER PROTON, THE OTHER PROTON’S VELOCITY IS LESS THAN THE SPEED OF LIGHT.

      Said again: when object A (the first proton) observes object B (the second proton) approaching and passing by, the velocity of B will always be observed BY OBJECT A to be less than or equal to the speed of light. Each proton observes the other proton approaching at less than the speed of light.

      But this does *not* contradict the statement that when object C (in particular, you and me) observes object A (the first proton) approaching object B (the second proton), C may indeed see the distance between A and B shrinking faster than the speed of light.

      How are these things consistent? They are consistent because ***distances and times from C’s point of view are distorted from the distances and times observed by A.*** The distortions are clever enough to assure that object A sees object B approaching at less than the speed of light, even though C sees the distance between A and B decreasing at a faster speed.

      Note also that C sees both A and B moving slower than the speed of light. The only thing that is changing faster than the speed of light, from C’s point of view, is a DISTANCE between A and B. But no OBJECT is moving faster than the speed of light from C’s point of view. It’s a subtle, but crucial, distinction. Einstein’s equations prevent the second from happening, not the first.

      Specifically, if you work through the distortions of space and of time that arise in Einstein’s theory, you will find that if the velocity of A relative to C is v1, and the velocity of B relative to C is v2 in the opposite direction, then A will observe B approaching with a speed which is

      (v1 + v2) / (1 + [v1/c]*[v2/c])

      which you can check

      (a) is just about equal to v1 + v2 (the result we’d normally expect in daily life) if v1 and v2 are much less than c, and

      (b) is just a tiny bit less than c if v1 and v2 are just a tiny bit less than c.

      So it all has to do with the fact that in Einstein’s equations distances and durations are changed from daily experience. And this isn’t speculation; it’s all verified in innumerable experiments, including ones that undergird some of the technology of modern life.

      1. You Rock and I thank you for your time. I would have kind of expected the particles traveling toward each other to have a condensed space time in the forward direction. But I still haven’t grasped the distortion of space time in the opposite direction. Maybe some other day you could lend your smarts. Best Wishes

        1. Relativity is very, very tricky. It’s not easy to get it right; I learned it in my freshman year of college and didn’t get it completely straight until junior year. There is a reason why it took a genius to figure out that such crazy-looking mathematics with bizarre counter-intuitive consequences could all work out so beautifully. It’s not enough to say that the speed of light is a maximum; you have to make space and time do strange gymnastics to make that statement consistent.

          But it’s actually the way nature works.

          This is why I love doing physics. The world is SO much more subtle than it appears…

          1. I look forward to more of your posts. If you could put to bed the whole thing about the bodies moving away from each other that would realy help me understand. I am not sure it is what you do but I was trying to write a computer simulation of gravtational lensing and it seemed counter intuitive to me. I have read that heat or electromatic energy can bend light. And it seems to me that with black holes light bends in wards not outwards. So after doing a little research I have only read about experiments that made measurements around our sun other stars or galaxies. Have any of the deep space probes proven that this occurs around any of the larger planets in our solar system. I hope I am not bothering you. But till now you have been the only person that has gotten me closer to not being one of the crazies.

  10. You have given me the best, easiest to understand answer to date. I really appreciate it. And unless someone actually breaks the speed I will go quietly into the night. Thanks again for a great post and to answering at a level I can understand. Best Rick

  11. What a great post and the replies are all amazing. I really enjoyed John Ryskamp’s input. I am but an enthusiast and in my limited abilities I believe there is a logical fallacy in stating nothing can travel faster than the speed of light. First I was told it was due to relativistic mass. Then I was told “real” physicists no-longer use that. Then I read it all has to do with a Lorentz Transformation having a static observer frame. And then I read it would take a device greater than 16,800 miles long to stop time for one second. The basic reading of relativity to me is that All laws of Physics are true for each inertial observer within their Minkowski World Line. So to me once an object reaches a constant velocity different than any other observer’s it is then in it’s own World line and the laws of physics would then pertain to it’s new space time, not the original or any other observer’s frame. No matter how this plays out I have really enjoyed taking the time to read more about this. Best to All.

    1. Well — I think you had it right the first time, just the wrong terminology.

      Particle physicists do not use “relativistic mass”, because it really is just another term for “energy divided by the speed of light squared”, with no other content. We only use “mass” for what used to be called “invariant mass”. Mass, by modern definitions, is relativistically invariant (i.e. all observers agree on what the mass of an electron is.)

      But particle physicists DO use “energy”. And what people used to say is true for “relativistic mass” is still true for energy: the energy required to push something close to the speed of light grows without limit. If you make a massive particle more energetic, it will go faster, but the degree to which it will go faster keeps decreasing, so that no matter how much energy you put in, the speed of the particle gets closer and closer to the speed of light but does not pass it. It’s not an issue anymore of a logical fallacy; it’s an experimental observation. At the main ring of the LHC, the protons there are accelerated from 450 GeV of energy to 4000 GeV. At the start of this process their speeds are already very very close to the speed of light, and at the end their speeds are very very very close. An increase of the protons’ energy of nearly 9 times makes almost no change in the protons’ speeds.

      I should add that I don’t agree with any of Mr. Ryskamp’s points.

      1. Matt:

        Let me know WHY you disagree. The question of course is: is not “natural” a constructivist intervention? I think it’s pretty obvious, once it is pointed out, that it is.

        This is how Einstein phrases it in the original German: “fallt zwar…zusammen.” It’s the zwar which causes the problem.

        By the way, if you look at the French and Italian translations of RELATIVITY, you will see that, consciously or unconsciously, the translators try to correct for this illogical intervention by “correcting” what Einstein says. That is, they mistranslate.

        In the end, I think you will see that it is Feynman (along with such books as The Hunting of the Quark–a story of vanity, hubris and careerism gone rogue) who put historians on to trying to find out the intellectual background of that Christmas tree we call the Standard Model. Feynman couldn’t do it–he had too much careerism invested the Standard Model. But he understood that nothing lasts forever.

        And really, Matt, how long do you suppose arguments are supposed to hang around before people find a flaw in them. Is that NEVER supposed to happen? It didn’t take Leibniz long to locate logical problems in Newton. Do you really think NOTHING is EVER supposed undermine Einstein’s logic? Come on, get real.

        A big clue for historians was that developments in set theory occurred precisely at the same time Einstein was developing his thinking. You really think that new flourishing of highly pernicious constructivism was not supposed to influence him? If you want to know the intellectual world in which Einstein developed, read Grattan-Guinness and Ferreiros.

        You really ought to read Garciadiego before coming out with a lame, unsupported statement that you just “don’t agree.” As if I’m “attacking” Einstein on logical grounds, and you’re defending him! It’s ridiculous. If Einstein was alive, he’d say there is nothing to “disagree” with. Why are you embarrassed that someone finally shows you how Einstein did what he set out to do? It’s because you mistakenly assumed that certainly relativity must be an internally consistent argument. That was your slip-up. You were not careful enough in investigating what Einstein set out to do, before signing off on what he did.

        All of which is to say that you’re not a constructivist. Good for you!! Why be ashamed of it.

        In any event, relatvity is quite over for anyone who was vain enough to think it had logical content. There’s no getting over “zwar”–and I did my homework!! No one gets around my logical objection.

        Thank you Feynman, wherever you are, for that wonderful conversation we had in Berkeley!! I’m still here, if you ever fly down from wherever you are!

        And now–on to Pythagoras!!!!

      2. Sorry to bother you again but could you tell me if this makes any sense? Why we can travel faster than the speed of light* –Going back to an earlier example of a sprinter running a 100 yard sprint on a long train car. Say the faster this sprinter could ever run is 100 yards in 10 seconds. That is a his universal limit. The train is passing an observer standing at the train station going 100 yards per second at a constant velocity. The sprinter starts the race right as he passed the observer. In 10 seconds he has traveled 100 yards on the train car. The observer notes that the Sprinter covered 1100 yards in 10 seconds. Now we know that the sprinter can only cover 100 yards in 10 seconds. So giving that time is close enough to the same for both the sprinter and the observer the only relative difference is distance. So within one observers frame or World Line all laws of physics must hold true. This is not the case going from one to the other. As a traveler reaches new constant velocities distance must be re-calibrated to the inertial frames. So given that CERN is only measuring an observation occurring from one frame in a very short period of time Einstein’s truth that nothing can go faster than the speed of light holds true. The distance and time never had to be re-calibrated. All Physical Laws must hold true for an inertial frame.

    2. The professor probably explains it better, but all you have to do is the math (high school algebra) for special relativity to see why nothing can go faster than light.

      1. Thanks Andy. I understand the high school algebra. Initially when I heard that it was possible to go faster than the speed of light I actually went back to the words that were written not just the math. I realize now that it is no-longer a debate but I found concern with the word velocity and how a Lorentz Transformation could have a “static” frame. So I took a gigantic crazy leap in thinking it should have been an acceleration not a velocity. But alas the universe to me is far less interesting than what I was hoping it could be. And I accept that. The Professor here is a great guy and I like the fact that he answered my question in a very easy to understand way without being condescending.

  12. A K: OPERA-2 used pulses extremely shorts (3 ns) separated by intervals of 524 ns. It made possible to measure the speed of each neutrino individually. With the method used for OPERA-1 was not possible to reach the same accuracy.

    The ICARUS detector is different to the OPERA´s. The ICARUS detector is composed by two semi-independent, symmetric, filled with liquid argon modules of approximately 3.6 x 3.9 x 19.9 cubic meters.

    In OPERA, the tau leptons resulting from the interaction of tau neutrinos will be observed in bricks of photographic films (“nuclear emulsion”) interleaved with lead sheets. Each brick has an approximate weight of 8.3 kg and the two OPERA targets contain about 150000 bricks arranged into parallel walls and interleaved with plastic scintillator counters. Each target is followed by a magnetic spectrometer for momentum and charge identification of penetrating particles. During the data taking, a neutrino interaction is tagged in real time by the scintillators and the spectrometers, which also provide the location of the bricks where the neutrino interaction occurred.



    1. JFP, I agree with all that. My posting has to be read in context. I was responding to Matt’s question much further up:

      ” Not impossible; but still, why did OPERA-2 and ICARUS get different results? They did their experiments simultaneously.”

      You need to read that entire thread to get the context. If you can get past Ryskamp’s metaphysics noise, that is.

  13. OPERA-2 differed from OPERA-1 only on the CERN side; nothing was reset on the LNGS side (at least nothing is mentioned in what they published). So whatever drift error had creeped into the system years ago could continue to be present. ICARUS, on the other hand, has parts of the system brand new (the fiber optic cable connecting outdoors to the underground lab, plus some associated electronics modeled exactly on OPERA). Come May we will know for sure.

    1. Actually, we won’t know anything by May. Posterity will say that this fraught development was the beginning of a different point of view entirely.

  14. “which dictates that real progress can never happen any other way, as a law of nature. Already in particle physics, constructive mathematics has found a foothold, in modern combinatorial twistor methods, in esoteric corners of M theory, and in many applications of logic. Does the CERN/GS laboratory contain the Earth, or does it not? For which/what observers? What are the observational contraints of each experiment?”

    I suggest that now that we know that “natural” coincidence is logical flaw–the constructivist intervention–in the relativity of simultaneity, physicists will cease to believe that “real” progress with respect to “nature.” They never believed this anyway, except in default of an explicit flaw in the logic of the relativity of simultaneity. Now we know what that is. Constructivism is unmotivated, so it can never contribute to “real progress.” Nor are its advocates, advocates of “real” progress, since they don’t believe in objectivity, because for them objectivity always ends in paradox.

    There is simply no way to any longer defend the constructivist point of view in physics. It is simply over, and whether that offends anyone’s amour propre or not, is irrelevant. There is no recourse to “larger systems,” there is no recourse to “renormalization.” There is no retreat from the constructivist intervention Einstein made in relativity.

    You have to understand that there has been a lot of pride and careerism in physics, and when those two get together, it is HIGHLY unlikely that settled principles will be revisited for a LONG time.

    Well, it’s been a long time. And when you have even people like Feynman backing away from the Standard Model, well, there are problems.

    And don’t feel put upon. The project of “unpacking” constructivism and examining the various disciplines into which it managed to weasle its way during the twentieth century, has been going on for quite some time. I wrote a very brief introduction to some of this literature. Here is the link. This is where, and when, I noted the constructivist intervention in the relativity of simultaneity. I wish someone would point out to me where it is in the Pythagorean theorem–that would be very great progress, and I am kind of hoping the duelling experiments will provide some insight into that:


    I think after you read the discussion of relativity in this paper, you will realize that it is quite over as an argument. The only thing left to deal with are its advocates’ careerism and vanity.

    1. Constructivism is unmotivated, so it can never contribute to “real progress.”

      Complete bullshit. My PhD was in constructivist mathematics. There are no rules about what mathematical techniques physicists are permitted to use in the construction of a theory of quantum gravity. In fact, many use constructivist ideas, such as toposes. Physics requires only (i) mathematical reasoning and (ii) measurement numbers.

      I do not disagree with your main point regarding SR. But that was 20th century physics, and we are now trying to understand 21st.

      1. The problem is that if there is logical problem with the relativity of simultaneity, there is no way, using ANY approach, to formulate “a theory of quantum gravity.” Those are all terms of art within the Standard Model, and mean nothing if there is a problem with the relativity of simultaneity. No one understood this better than Feynman, which is why he died dissatisfied. But he didn’t know WHY he was dissatisfied. Now we know. Too bad he died when he did. Before you express outrage, you really ought to find out if there is any thing for you to get outraged about. That is why you should begin with Garciadiego. What he reveals should humble any researcher.

      2. You’re not getting this. SR and GR are successful physical theories. In physics, it doesn’t matter at all what twisted logic went into the theory, if it gives the right answer in a repeatable experiment. SR goes beyond Newtonian mechanics in discussing speeds comparable to c, and anyone who says otherwise is a complete idiot.

        Now, physics has progressed since then. Of course the SM was not formulated correctly in the 20th century. Every physicist knows that. But current progress in a reformulation of the SM, about which you probably know absolutely nothing, is Constructivist. That is, the language for discussing the SM is totally different to what it once was. This has to be a big hint about the kind of mathematics required for QG, and without new physics, there is no progress, and we become extinct, as we no doubt deserve.

        1. Oh I think I’m understanding it VERY well. The “success” is artefactual. And I certainly have answer to this:
          “In physics, it doesn’t matter at all what twisted logic went into the theory, if it gives the right answer in a repeatable experiment.”

          ‘Insanity is doing the same thing, over and over again, but expecting different results.’ – A. Einstein

          I believe that is called, being hoisted by your own petard.

          “This has to be a big hint about the kind of mathematics required for QG, and without new physics, there is no progress, and we become extinct, as we no doubt deserve.”

          Oh dear….This is wandering into the didactic, n’est-ce pas?

      3. You’re not much of a logician, since you have failed to understand even the most simple arguments. And you have conveniently ignored the terms that you don’t know the meaning of. Anyway, I am tired of talking to ignorant know-it-alls.

  15. Prof. Strassler,

    It is precisely when brilliant, creative, famous, credible people play underhand politics that things get annoying. It affects the world more.

    But I am straying from the topic. Come May, I suspect OPERA will repeat their original result, while BOREXINO and LVD won’t. I am not so sure of ICARUS–the accumulation of the +ve values toward the end (something with a 5% probability of occurring by random chance, assuming a 3/3 split among + and – values among the last six) seems to point to an error accumulating over time. Perhaps an error saturating at +60 ns (ICARUS uses the same system as OPERA past the immediate detector stage).

    1. I think you are reading way too much into 7 events. Two of the events are consistent with arrive right on time (given the timing uncertainties) so there are five events, of which two are late and three are early (or reverse, I forget). The probability of this is like the probability that you flip a coin five times and three in a row are heads and two are tails. Or the reverse (since you would have probably complained if it had been the other way.) Well, you can work that out; this probability is not particularly low.

      Plot the seven events on a graph; it is not at all an impressive trend. The statistics are far too low to say “trend”.

      Suppose you were right — there is an drift problem. ICARUS and OPERA-2 made their measurements at exactly the same time, in the same beam, with the same system (as you say) up to the immediate detectors. The problem is too slow to cause a 60 nanosecond shift within the system that the two experiments share; so you are asking ICARUS to have a negative 60 nanosecond shift to exactly cancel the true positive 60 nanosecond shift. This is not very plausible. It is much more plausible that OPERA made a mistake — especially since they have already withdrawn their previous result for the moment due to the issues that they found.

      1. No, I am not saying the ICARUS “luminal” result is wrong. I am saying it is right. But the way their values are structured, they do have a drift. I think it is the same drift OPERA is also seeing. In other words, that drift is indicative of the error OPERA sees. ICARUS escaped the same conclusion simply because they stopped their experiment before the drift became serious enough to overwhelm the early, correct readings.

  16. Although it is probably fair to put a higher probability on an OPERA error, at this point, I believe John’s comments are the tip of an iceberg. Note that the 60ns ‘GR’ correspondence was pointed out by many people during the theory kerfuffle following the initial OPERA announcement. Certainly, now both ICARUS and OPERA must be repeated by other groups.

    John criticizes constructivism, but there do exist serious physicists who still hold a constructivist view, which dictates that real progress can never happen any other way, as a law of nature. Already in particle physics, constructive mathematics has found a foothold, in modern combinatorial twistor methods, in esoteric corners of M theory, and in many applications of logic. Does the CERN/GS laboratory contain the Earth, or does it not? For which/what observers? What are the observational contraints of each experiment?

  17. You say “if it has not mass it has not any property as electric charge or magnetism and also spin”.

    This statement is wrong. Neutrinos, even if they were massless, would have spin, and if the Higgs field’s value were zero, the electron would be massless and have electric charge and spin.

    However, that statement is also irrelevant. Neutrinos are believed to be massive, but their masses are very small compared to the energies that are carried by the neutrinos in the CERN beam. If you have a particle with mass of 0.01 eV/c2, which would be a reasonable guess for what the neutrino mass might be, and its energy is 10,000,000 eV, then its speed is slower than the speed of light by a tiny factor, 0.000,000,000,000,000,005. That difference from the speed of light is far too small for ICARUS to measure. That is why it appears to ICARUS that the neutrinos arrive, TO WITHIN THE UNCERTAINTIES OF THE MEASUREMENT, at the speed of light.

    Another way to say this is that the fact that ICARUS finds the neutrinos traveling at the speed of light, TO WITHIN THE UNCERTAINTIES OF THE MEASUREMENT, tells you that neutrinos have a mass that is less than a thousand eV/c2 or so. But we knew that, long ago, from other measurements, so this is not news.

    1. “perhaps the idea that two points can be infinitely close together is wrong—the assumption that we can use geometry down to the last notch is false. If we make the minimum possible distance…the smallest distance involved in any experiment today…, the infinites disappear, all right—but other inconsistencies arise….”
      Feynman, QED

      When, having understood Einstein’s contructivist intervention, you see someone as intelligent as Feynman using terms such as “infinitely close” and “last notch,” you realize how hopelessly muddled–not to mention ill-informed–contemporary physics is. Today’s physicists are even sloppier than Godel–and that’s saying something!

      ICARUS and OPERA are two drunks fighting in an alley–and they’re fighting about who agrees more with the other. Silly people.

    2. People have been making and using neutrino beams for decades. They have used them to study properties of the proton, and then used what they learned about the proton in other experiments, with great success. To suggest neutrinos don’t exist is just as silly as suggesting that photons and electrons don’t exist.

      In fact, the sun has been “neutrino-graphed” — observed in neutrinos as directly as one observes the sun in a photograph:


      This was done deep underground where no other particles can penetrate. If neutrinos don’t exist, how could you obtain this?

      You can read


      There are many specific ways to detect neutrinos and each experiment does it slightly differently, but the basic strategy is that a high energy neutrino will sometimes hit a nucleus and shatter it, or hit an electron and cause it to recoil rapidly — effects that are easily detected.

      1. Remembering, of course, that “neutrino” is a term of art in that dead language called the Standard Model. Of course, since we don’t yet have any replacement model for the Standard Model, we don’t know what to say, or whether this “neutrino” is an artifact.

  18. He doesn’t have time to answer such questions. He is too busy reading A. Garciadiego, BERTRAND RUSSELL AND THE ORIGINS OF THE SET-THEORETIC ‘PARADOXES.’

  19. @guest: suggesting Carlo Rubbia, who already has a Nobel Prize, would sacrifice his place in history and his huge achievements by lying about the ICARUS data, and that his dozens of collaborators who signed the paper would go along with it, is ludicrous.

      1. Rubbia and politics go hand in hand. However, I know people who worked closely with him, and have heard plenty of stories. To say he is `no science’ is, again, ridiculous. And he does have a reputation to protect, for the history books. Lying about your data is grounds for permanent censure and loss of your job.

  20. Wow ‘guest’! I thought I was bad! No one, I repeat, no one wants those neutrinos to be moving at v > c more than I do. Einstein is a hero to me, but I hate both Special and General Relativity! The first limits us to the snails pace of light speed in a universe where we need at least 500c to make interstellar travel a bearable reality, and the second makes no real connection wth other areas of physics and contains within it no realistic way to manipulate the force it so “beautifully” describes: gravity. I cannot wait for the day when this edifice falls…and some day it will fall, but in physics, like everywhere else in life, you have to know when to fold.

    OPERA has said it could have had a technical problem that resulted in v > c neutrinos when in reality they were v = c. Now ICARUS has data that also show v = c. As much as I want the data to be wrong – the data is the data. One thing I will never beleive is that the data has been intentionally manipulated to show Einstein correct. I guess I have faith in the people both at OPERA and ICARUS to report what they find – not what they (or I)desire.

  21. I will not be surprised if the history books, say 100 years from now, has a chapter that tells the story about ICARUS and OPERA collaborations that in 2012 manipulated their data / instruments in order to falsifie the superluminal behavior of neutrinos. The superluminal nature was such a scary threat to the established physicists-community that they was lead by emotions and manipulated the data. I therefore look forward to the minos-experiment on neutrino velocity and hopefully the researchers there are honest / totally neutral!

    Even if the paper from ICARUS sum up their results to v(Neutrinos)-C=0, it is not possible to forget that their details in the paper revealed some neutrinos that actually was superluminal up to 19 nanoseconds over C! And if we compare this to the fact that they only measured 7 neutrinos it make me suspicious. Have they handpicked those seven neutrinos so that the average result should be excactly at C ! ?????


    Before it all “goes away” (if it does), you should remember what is at issue: is there a logical problem with the relativity of simultaneity? On this issue, there have been developments from an unexpected source: the historiography of set theory, and your readers should know about them. We are in the midst of a renaissance in the historiography of set theory, and it has revealed a lot about Einstein’s intellectual orientation. You should keep this in mind as these “duelling experiments” go on. They have a bearing on what Einstein put into the relativity of simultaneity.

    The chief book in this new historiography is Garciadiego, BERTRAND RUSSELL AND THE ORIGINS OF THE SET-THEORETIC ‘PARADOXES.’ Other chief contributions are by Ferreiros and Grattan-Guinness.

    You have to step back for a moment and realize that constructivism has been the chief project of the west since Aristotle, who made logic’s task that of “heading off” Zeno’s paradox. Constructivism says that argumentation inevitably leads to paradox, so there must some arbitrary intervention in every argument, some intervention which destroys the logic of the argument, but avoids having the argument end in paradox.

    What is the justification for this proceeding? Well, it has nothing to do with logic. It is simply a “feeling”–imported into the argument in the form of an intervention–that argumentation is “inherent” in humans and that this must somehow find its way into any argument.

    There is no claim that constructivism makes any sense. It is an article of faith.

    Einstein was a constructivist, and this is where the set theory historiography comes in. There was a new constructivist “flowering” with Cantor and the establishment of set “theory,” and Poincare in particular was a publicist for it. Einstein was enthusiastic about Poincare’s Science and Hypothesis and never had a bad word to say about it. How much did Poincare understand about logic? According to Grattan-Guinness, “not much.”

    You should also realize that none of the candidates for “paradox” have stood the test of time. Their “paradoxical” character is an artefact of the construction of the argument (I note that this is one commentator’s conclusion about the OPERA results). This is one of the chief contributions of the new set theory historiography (and here is where Garciadiego is particularly important: there is no Russell paradox, there never was a Burali-Forti paradox, and so on–very eye-opening stuff).

    So the notion is unmotivated that there must be an arbitrary intervention in an argument in order to prevent it from ending in paradox.

    However, Einstein didn’t know that at the time he formulated the relativity of simultaneity. In fact, he was a convinced constructivist all his life, and his profession de foi is, of course, “Geometry and Experience.” Here is a comment of his which shows the influence of constructivism on his thinking about geometry:

    “It is clear that the system of concepts of axiomatic geometry alone cannot make any assertions as to the relations of real objects of this kind, which we will call practically-rigid bodies. To be able to make such assertions, geometry must be stripped of its merely logical-formal character by the co-
    ordination of real objects of experience with the empty conceptual frame-work of axiomatic geometry. To accomplish this, we need only add the proposition:–solid bodies are related, with respect to their possible dispositions, as are bodies in Euclidean geometry of three dimensions. Then the propositions of Euclid contain affirmations as to the relations of practically-rigid bodies.”

    It is important to note that these statements play no logical role at any stage of the relativity of simultaneity. “Alone” and “merely” and “add” are not notions any scientist today would support–they are vague, even sloppy. However, they have passed without comment because it was never clear exactly where Einstein made a “mistake” (actually, it’s not a mistake, it’s an intentional intervention). So Einstein could “get away” with them as long as no one could “catch” him making a logical error.

    The question is, then, where did he make his arbitrary insertion in the relativity of simultaneity? It’s there by implication in the 1905 paper, but here he makes it explicit (in RELATIVITY):

    “Are two events (e.g. the two strokes of lightning A and B) which are simultaneous with reference to the railway embankment also simultaneous relatively to the train? We shall show directly that the answer must be in the negative. When we say that the lightning strokes A and B are simultaneous with respect to be embankment, we mean: the rays of light emitted at the places A and B, where the lightning occurs, meet each other at the mid-point M of the length AB of the embankment. But the events A and B also correspond to positions A and B on the train. Let M΄ be the mid-point of the distance AB on the traveling train. Just when the flashes (as judged from the embankment) of lightning occur, this point M΄ naturally coincides with the point M but it moves…with the velocity…of the train.”

    The intervention is, of course, “naturally,” a notion which plays no role in the logical of the relativity of simultaneity. It’s typical of an insertion of this kind that the resulting formulation can’t do with the insertion, and can’t do without it. Clearly it is not an assumption, principle, hypothesis, deducation, conclusion, or any other identifiable rhetorical part, of the argument: it plays no logical role in the argument, period.

    But note what happens if you remove “naturally.” The two parallel lines coincide at all points, and we are looking at one system, not two. This contradicts the assumption of two systems.

    This is is the manner of a classic disproof: the part of the argument under discussion is one which is not part of the argument, and cannot removed from the argument, either. End of argument.

    I go through all this in order to caution readers that the duelling experiments are not about find a logical flaw in relativity. This is because Einstein never intended to make relativity an internally consistent system, and did not do so. He was a convinced constructivist, who did not think an internally consistent argument was ever possible.

    Instead, scientists should look to their OWN assumptions about relativity and about argumentation. There aren’t many constructivists today. It so violates our commitment to logic–it is so vague–that we don’t tolerate it.
    Troelstra recently succinctly formulated the constructivist position. It is startling (to most people) to think that the following (drivel) is also Einstein’s intellectual orientation:

    “Constructivism is a point of view (or an attitude) concerning the methods and objects which is normative: not only does it interpret existing mathematics according to certain principles, but it also rejects methods and results not conforming to such principles as unfounded or speculative (the rejection is not always absolute, but sometimes only a matter of degree: a decided preference for constructive concepts and methods). In this sense the various forms of constructivism are all ‘ideological’ in character….Characteristic for the constructivist trend is the insistence that mathematical objects are to be constructed (mental constructions) or computed; thus theorems asserting the existence of certain objects should by their proofs give us the means of constructing objects whose existence is being asserted.”

    Now read it as a description of relativity:

    “Relativity is a point of view (or an attitude) concerning the methods and objects which is normative: not only does it interpret existing mathematics according to certain principles, but it also rejects methods and results not conforming to such principles as unfounded or speculative (the rejection is not always absolute, but sometimes only a matter of degree: a decided preference for relativistic concepts and methods). In this sense the various forms of relativity are all ‘ideological’ in character….Characteristic for the relativist trend is the insistence that mathematical objects are to be constructed (mental constructions) or computed; thus physical theories asserting the existence of certain objects should by their proofs give us the means of constructing objects whose existence is being asserted.”

    It has to be disturbing to any scientist that Einstein would not have disagreed with any of that.

    Of course, no scientist likes to think of relativity as a polemic, and scientists have been justified in this, because no one bothered to point out exactly how and where Einstein carried out his constructivist program in formulating the relativity of simultaneity. But now we know just how he did it.

    So, the duelling experiments are neither right nor wrong, because there is nothing–pertaining to relativity–to be right or wrong ABOUT. These are experiments along the rather serpentine route to scientists arriving at a consensus that “natural” coincidence is Einstein’s intervention in the relativity of simultaneity.

    The interesting question is: what argument is going on in the GEOMETRY of these duelling experiments, showing us that scientists are finally coming to grips with Einstein’s constructivism?

    By the way, according to Einstein, reality is progressive. Do you believe it?

    And by the way, assuming that the Pythagorean theorem is trying to avoid ending in paradox, where is the constructivist intervention in it? Happy hunting!!

    Of course, no scientist likes to think of relativity as a polemic, and scientists have been justified in this, because no one bothered to point out exactly how and where Einstein carried out his constructivist program in formulating the relativity of simultaneity. But now we know just how he did it.

    So, the duelling experiments are neither right nor wrong, because there is nothing–pertaining to relativity–to be right or wrong ABOUT. These are experiments along the rather serpentine route to scientists arriving at a consensus that “natural” coincidence is Einstein’s intervention in the relativity of simultaneity.

    The interesting question is: what argument is going on in the GEOMETRY of these duelling experiments, showing us that scientists are finally coming to grips with Einstein’s constructivism?

    By the way, according to Einstein, reality is progressive. Do you believe it?

    1. John Ryskamp, you long comment is not about physics but is metaphysics which of course is fundamentally important to physics.

      John Ryskamp: “Constructivism says that argumentation inevitably leads to paradox, so there must some arbitrary intervention in every argument, some intervention which destroys the logic of the argument, but avoids having the argument end in paradox.”

      Now (not at the time of Special Relativity and General Relativity), it is well-known that all axiomatic systems will inevitably produce at least one paradox after the publication of Godel’s theorems, and an arbitrary intervention can eradicate a paradox of the current system but not for the enlarged system. In physics, we do not introduce an arbitrary intervention but with a very carefully selected intervention which we call it “renormalization.” That is, physicists today do understand this issue somewhat.

      Furthermore, both SR and GR are internally consistent in terms of the “physical universe” while they are indeed not able to escape from the slaughter by the Godel’s theorems. It is both of them preventing of constructing a unified gravity theory under their current interpretations (interventions). And, this problem goes way beyond the issue of relativity of simultaneity. And, I do not see any connection between this Einstein problem with the dueling experiments. Einstein’s metaphysics problem goes way beyond the current physics.

      1. Hi:

        Your comments are interesting, but reveal that you are not current on the literature, and it was to encourage people to become current with what is going on, that i wrote it. I am not in the least interested in metaphysics and I don’t think my comments are in the least metaphysical. I am interested in internal inconsistencies, if any, in arguments. You should address yourself to “natural” coincidence in Einstein’s formulation–stick to what he wrote and address the logical problem. The point is that it is not “well known” anymore that “all axiomatic systems will produce at least one paradox,” and you cannot rely on Godel anymore for that statement. Among other things, if you read the commentary by Feferman et al. in the Godel Works, you will see that Godel’s constructivism led him to be quite sloppy, and we are pretty far along the road to identifying where Godel makes his own constructivist intervention. I think the problem identifying it is that, once you become really critical of his theorems and their constructivist orientation, you begin to wonder if he is making any argument at all (this is the same objection being made about Cantor). Certainly statements of Godel’s should make you wonder. For example, he refers to Richard’s paradox as if it has some logical content, but we know perfectly well that it has none. Richard himself knew that. But apparently Godel doesn’t. Strange. Godel was not careful enough.

        I really wonder if the issue is “eradicating a paradox in a larger system.” As for renormalization, on page 128 of QED you will find what Feynman said about renormalization. He called it a “shell game.” You rely on renormalization and Feynman didn’t? Interesting. You really call that renormalization an answer to the idea that “natural” coincidence is a constructivist intervention in the relativity of simultaneity? Odd. Also, revisit the notion that there is “larger system.” If there is no paradox, there is no “larger system” as you conceive of it.

        The point is not that renormalization is “arbitrary,” the point is that it is constructivist. Your own point of view seems to be an unexamined constructivism. What I am saying is, go back and examine it; grounds exist to go back and examine it. I doubt there there is anything “way beyond,” if there are logical problems with the relativity of simultaneity.

        Also, you should entirely abandon the idea that Einstein was interested in promulgating a system which was in any way, on any terms, “consistent.” You seem to still have some personal investment in what he wrote. Divest.

        Won’t it be a funny joke if ICARUS is arguing the clock experiment and OPERA is arguing the train experiment, when they are the same experiment and mechanically translatable one into the other?

        You should really read Garciaidiego. When I say set theory historiography is revisiting settled arguments of physics, that’s what I mean. Physics is being blindsided by this look into the intellectual origins of relativity. It’s really a political, not a scientific, history. Relativity is pure politics. Fairly sophisticated politics. But politics. That’s what I meant by “duelling” experiments. Perhaps they are still duelling, and the war is over.

  23. Tienzen (Jeh-Tween) Gong, honestly, I have nothing new to add to my previous comment. Simply to point out that the concept of universe tied up to the Einstein’s theory is a universe with four dimensions, built up for a terrestrial observer tied up to a universe fourth dimensional. Seems obvious that a particle as the neutrino, that is a massive particle, runs away the canonical theory, it means that any theory is subject to be improved irrespective of the Alpha frame.

  24. Actually the terrific Daya Bay neutrino oscillation result is way, way, more interesting than this marginal science. ICARUS has been a 25 year spectacle of missed opportunity.

  25. I read “Measrement of the neutrino velocity with the ICARUS detector at the CNGS Beam” and found no mention of the energy of the 7 muon-neutrinos events that were detected. As ‘A K’ noted above the paper mentions a detection trigger threshold as “low as a few hundred MeV with full efficiency”. Table 1 seems to have many details of the 7 events – with the glaring exception of energy. However, I assume, until I hear otherwise. that the energy of the 7 events was, like OPERA, in the tens of GeV range. Otherwise it may well be like comparing apples and oranges – and those side-by-side ICARUS VS OPERA charts may be telling us something very different than we think.

    1. The original CNGS beam produced neutrinos with average energy of 18 GeV. OPERA-detected neutrinos for their first experiment (the one reported on Sep 22nd) had an average energy of 28 GeV, indicating OPERA was more sensitive to the higher-energy range (see their arXiv paper 1109.4897)

      I am not sure whether the neutrino energies of the short-pulsed beam are the same as the original CNGS beam. ICARUS does point out one detection produced very low PMT (Photomultiplier Tube) light, which I presume means a lower-energy neutrino (see the footnote to their table 1; the same footnote implies for all other cases the PMT signal size was higher and similar to one another). But is there a reason to assume ICARUS would miss higher-energy neutrinos? The probability of a collision should be the same independent of energy, and the chances of detection better for higher-energy. How could higher energy (or higher speed) allow a neutrino to barrel through what it would have struck otherwise?

      The “external” muon events probably work the same way – I guess it is reasonable to assume, though we don’t know for sure, that muons inherit energy and velocity from the neutrino which strikes to produce them.

      1. One correction to the above: faster neutrinos will manage to avoid moving objects better simply because they spend less time in a collision-possible area. But the idea ICARUS missed superluminal neutrinos because they managed to evade the Liquid-Ar neutrons better is too far-fetched. None of the neutrinos ICARUS detected is superluminal in the sense OPERA detected with the same beam. There is zero intersection between the two sets of data. (The “external event” muon argument is immaterial – one can assume muons inherit the energy and speed of the neutrinos birthing them).

        That said, yes, data on energy would have helped. Everybody is in a hurry when it comes to anything to do with the OPERA results. I think one problem is the place leaks like a sieve. If Rubbia hadn’t gone public when he did, somebody would have leaked the results to Science’s Edwin Cartlidge, making things even messier.

        Autiero actually hasn’t conceded yet: See http://en.wikipedia.org/wiki/Faster-than-light_neutrino_anomaly
        and the reference it includes. I am not quite sure why he still isn’t sure. This isn’t a case of two conflicting results and our believing the one that matches conventional wisdom. It is more that we have to posit both experimental error and error that exactly cancels superluminosity in the ICARUS result if OPERA is to hold. For ICARUS to hold, all we need posit is experimental error in OPERA.

  26. Here are the (tof_c – tof_v) values arranged chronologically
    -6 0 -5 -19 +7 +3 +18
    (a slight correction: the right half is superluminal and left subluminal).

    Matt, any ideas on why the values should be so neatly split chronologically? Could be pure chance, I guess, since there are just 7 values.

  27. The distribution of the ICARUS values is interesting. See Table 1 of their arXiv paper. All the negative values (subluminal) are before 2 Nov 02:50 (Runs 10949 and 10950) and all the positive values (putatively, even if not statistically, superluminal) after 2 Nov 02:50 (Runs 10951, 10956). Looks like something or the other is breaking down over time. If the results had been unexpected, I am sure people would have pointed this out. Maybe I am biased because I want to believe OPERA’s results are real. Oh well, measuring neutrino velocity definitely looks hard – the ICARUS distribution is acceptable only because it matches the expected mean value.

  28. Tienzen (Jeh-Tween) Gon: I don´t fully understand your comment, you say that:

    “The light speed which is a true constant is guaranteed by the Alpha (Electron Fine structure constant) which is a dimensionless constant. Thus, even if OPERA’s data were not refuted but were confirmed, it would still have no power of challenging the Alpha”.

    As far as I know the speed of light was proposed for Einstein for a universe with three spatial dimensions plus time. We do not know anything about a universe that ripple to four, five o six dimensions. Then the speed of light is not a constant of nature for dimensions that are beyond the 3+1 habitual dimensions. The euclidean geometry was a natural frame until Gauss and Riemann got in the stage. To my mind is a mistake to face this issue around Einstein, I would say that the speed of light (300.000 km/seg) is a provisional constant whether the photonic domain seems to be an universal fact. There is nothing universal related to the human knowledge.

    I have no idea about the nature’s design, seems very difficult to understand the laws of nature unless we use the human knowledge (that is provisional and subject to falsation) to do it. I don’t believe in dimensionless constant for the simple reason that the instrument that describes the dimensionless constant is the human knowledge, which is provisional and subject to falsation. To use words like “ontological”, “universal” and similar seems to me meaningless.

    Anyway, I think that this issue is still an open question and needs more investigation.

    1. JFP: Thanks for your comment. I am not talking about ontology.

      This is not a place for me to discuss this issue in depth. I can however discuss a general idea.

      The Nature constants are Nature’s design and were discovered by human. As soon as after their discovery, they arose above all theories, all laws and all principles, as they are indeed Nature’s design. Any tiny bit of change of the value of those Nature constants will alter the laws of our universe dramatically. Yet, what the Nature constants are the true constants? Seemingly, the gravity constant (G) is not a true constant but evolves in time.

      It is our good luck (or Nature’s kindness) that there is the Alpha which is composed of with only three constants [light speed (c), electric charge (e) and Planck’s constant (h-bar)], without messing up with any other variables. Furthermore, Alpha is a clean dimensionless number, that is, it should be independent from any coordinates (reference frames) and variables and must not change in time or in space. Thus, it will not be a blind guess that c, e and h-bar are the three true Nature constants. Any change of one of the three constants will change the value of other constants while there should be no mechanism to change the value of Alpha as it is a dimensionless constant.

      Historically, Einstein could be the one of the first emphasized that the light speed is a Nature constant. It was his smart move for choosing that, and that choice made his SR theory to be correct. But, light speed to be a Nature constant is not a “consequence” of his theory but is a “prerequisite” for his theory. We should not confuse the cause-effect issue here.

      These three Alpha-constants define this entire universe.
      a. Light speed gives rise to an event horizon, and it is the base for a causal universe.

      b. The electric charge is the function of the square root of (c * h-bar), and it is the “viewing” window available for viewing this universe.

      c. The h-bar, being an innate angular momentum, gives the directionality of … .

      In my view, with only these three Alpha-constants, it is enough to construct a universe, and these three are firmly locked by Alpha, a dimensionless constant which cannot be altered by any reference frame or variable.

      Thus, regardless of the OPERA’s data being right or wrong, it can never change the fact that light speed is a Nature constant, guaranteed by Alpha. If OPERA turns out to be right, it must be caused by an effect which has nothing to do with the light speed being a true Nature constant.

  29. It is very nice that OPERA’s data was refuted directly with another set of data. Again, this is an excellent post.

    In physics, there are five parts.
    1. Laws — they are always correct in their defined domain.

    2. Principles — they should be correct universally, in all domains.

    3. Nature constants — they must be correct universally, as they are the measuring “rules” for the constructing of the universe.

    4. Theories — the human’s attempt to modeling the Nature’s design.

    5. Test data — the human’s attempt to verify the human theories.

    Among the first three (laws, principles and nature constants), the nature constants preempt all others. The theories and test data have absolutely nothing to do for the Nature’s design. Thus, all test data can never change the Nature’s design. So, OPERA’s data can only challenge theories, such as Einstein’s.

    The light speed which is a true constant is guaranteed by the Alpha (Electron Fine structure constant) which is a dimensionless constant. Thus, even if OPERA’s data were not refuted but were confirmed, it would still have no power of challenging the Alpha. It simply means that there is something else at work.

  30. Matt, I agree completely with your analysis of the ICARUS results then and now. For a few brief months I hoped we were at the beginning of the first great physics revolution of the 21st century. Guess not. This pretty much seals the deal (though I was wondering what the energy range of those 7 neutrino events was). Nonetheless, to get complete closure on this issue I do think that OPERA and other Labs that have previously agreed to should conduct further tests in this regard.

      1. Come to think of it a bit more, I think the case is indeed totally closed. The two experiment results are logically not on par. It is hard to see how an experiment can miss superluminality and end up with a value the speed of light (what possible error can you hypothesize?). It is easy to see how an experiment can see superluminality (or subluminality) where there is none. This isn’t based on one result being more plausible; it is just based on the probability one hits exactly the value ‘c’ as opposed to hitting an arbitrary value different from ‘c’ because of experimental errors.

        ICARUS hasn’t mentioned the energy of the neutrinos, but that doesn’t matter either. In their second run, OPERA saw superluminality for every detected neutrino, including the ones showing up as muons from the rocks (external events). So their measurement has errors.

      2. One other point: per http://arxiv.org/abs/1110.3763 ICARUS typically detects neutrinos in the 10 GeV range (that mean is after removing all < 500 MeV events). OPERA reported its results for 40 GeV down to 14 GeV (http://en.wikipedia.org/wiki/Faster-than-light_neutrino_anomaly). The energy range for the short-pulse beam has not been reported by OPERA either, but since the neutrino energy seems to be set by the magnetic focusing system at CERN and not pulse width, looks like it is the same as the CNGS beam – around 17 GeV mean. OPERA didn't see a statistically significant difference across energy ranges, but the trend was one of 'v' decreasing with energy (though the large standard deviations caused too much overlap, nullifying statistical significance). Actually this trend is one of the things hard to explain with the loose-connector argument (the other being the connector staying loose the exact same way over years).

        The energy difference seems unlikely to reconcile a fully luminal result from ICARUS against a fully superluminal result from OPERA. The only real open issue is what the OPERA error is – the fiber doesn't seem to cut it. There is also the annoying issue a Nobel-winner like Rubbia stoops to such low spin – his previous "refutation" of OPERA was nothing of the sort; it actually replicated OPERA's observation of no C-G decay.

  31. Hmm… 7 neutrinos having an speed from 0,3 ns faster than light with limits of + – 20 ns. Certainly the data is consistent with dt=0, it means that these neutrinos are not faster than photons but just as light.

    The events measured for OPERA-1 were around 14.000, a notable difference with the seven measured for ICARUS. The ICARU´s paper says that they launched the neutrinos from October 21/2011 to November 6/2011. But on November 18/2011 OPERA-2 measured 20 FTL neutrinos using short pulses. Seems that the detector used for ICARUS is different to the OPERA´s, I wonder if it is significant for the final result.

    Next measurements stand by: Opera-3, Borexino and Minos+. It seems that the MINOS team has been working hard to update the data obtained in 2007 (they detected speed diversions of 120 ns). They handle two analysis, the first one take into consideration the data studied along these years with an improved understanding of the electronic system. Right now they are taking data until April, next month the Fermilab acelerator stops to get ready the NOVA experiment. The MINOS team plan a new phase named MINOS+ that will increase the intensity and energy of the neutrino’s beam. Seems that they are not in a hurry to show the new results, the reason is that Fermilab has demanded to review the analysis thousands of times in order to avoid any trace of embarrassment.

    It would be advisable to wait for new measurements, in my opinion there are some unresolved questions blowing in the wind.


    1. The difference between 7 events at ICARUS versus 20 at OPERA-2 is nothing to be concerned about; they aren’t identical detectors so they’re not going to measure the same rates. The ICARUS people say that they expected something in the 5 to 10 range, so the number’s fine.

      OPERA-1 uses a completely different method which is why their numbers are so large.

      MINOS did NOT detect speed diversions of 120 nanoseconds. You give yourself away when you say something like that. It is 120 nanoseconds WITH A LARGE UNCERTAINTY. All measurements are X +- Y; if you don’t put in the uncertainty (especially if it is large) you give completely the wrong impression. The uncertainty on the MINOS measurement is so large that their result is consistent with NO speed diversion.

      You can wait for new measurements if you like; no one is going to stop you from waiting.

      1. A slight correction. ICARUS detected fewer events more because they had an error in their system which initially cause the DAQ not to see any neutrinos, causing them to miss a few days. But I don’t think that is particularly relevant. It is hard to think of an error that would exactly cancel out the purported 60 nsec superluminality (slightly less for ICARUS, at a -55m distance as compared to OPERA). ICARUS does share the external (outdoor) GPS system with OPERA. The differences are in the fiber cable (roughly similar length) bringing time underground, and the detector system. So OPERA’s error has to be in one of those systems.

  32. Does ICARUS refute OPERA? I say no. According to the ICARUS team, “The absolute UTC timing signal at LNGS is provided every second (PPS) by a GPS system ESAT 2000 disciplined by with a Rubidium oscillator …, operating on the surface Laboratory. A copy of this signal is sent underground every ms (PPmS) and used in ICARUS to provide the absolute time stamp to the recorded events.” The ICARUS method essentially compares neutrino speed directly to the speed of light, while the original OPERA method compares neutrino speed indirectly to the speed of light with the assumption that the Rañada-Milgrom effect does not exist. BELIEVE IT OR NOT.

  33. Concerning the ICARUS detector chambers (http://icarus.lngs.infn.it/DetectorOverview.php):

    The detector is designed to detect drifting electrons caused by neutrinos that collides into them. My humble question regarding this is: What if these electrons are only “physical able” to react to waves/frequencies (particle/wave duality) created by subluminal neutrinos and/or neutrinos that moves at C ? Superluminal neutrinos might cause different waves/frequencies that does not affect the electrons in the detector chamber at ICARUS. May be this is the reason for why they only were able to catch neutrinos at/or below C. It is my humble right to ask this silly question :-). OPERA’s detectors is designed differently: To catch the interaction between a colliding neutrino and a photographic brick directly.
    And this design might catch those superluminal neutrinos ?

    1. In both experiments, many of the measured neutrinos interact in the rock before reaching OPERA and ICARUS. What is measured by the experiments is the debris from that neutrino collision with an atomic nucleus in the rock. So differences in how the experiments themselves measure neutrinos are completely irrelevant. If they were relevant, the neutrinos that interact in the experiment and those that interact in the rock would have different timing. But neither OPERA nor ICARUS sees any difference in the timing between those two classes of neutrinos.

      1. This isn’t clear to me. Could muons produced by superluminal neutrinos themselves be superluminal? If so, would they be detected the same way by the solid detector (presumably static neutrons) and the liquid detector (presumably moving neutrons)? In other words, could the liquid detector with its somewhat-mobile sparser neutrons prefer lower-energy, presumably lower-velocity muons (and neutrinos), while the lead detector does the exact opposite?

        Not defending OPERA results here (these are far-fetched objections), just making sure we bury them with the right requiem 🙂

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