ADVERTISEMENT
  About the SA Blog Network













Life, Unbounded

Life, Unbounded


Discussion and news about planets, exoplanets, and astrobiology
Life, Unbounded Home

Superluminal muon-neutrinos? Don’t get your hopes up.

The views expressed are those of the author and are not necessarily those of Scientific American.


Email   PrintPrint



Ghosts in the aether (CERN)

The past 24 hours have suddenly been awash in neutrinos, in addition to the 65 billion passing through every square centimeter of your skin every second from the Sun’s core. Although hardly the stuff of planetary science or astrobiology I have found myself facing questions from a few people who wonder if faster-than-light particles could portend the coming of interstellar travel, or ‘sub-space’ communication (whatever the heck that is beyond a convenient scriptwriter ploy to keep a plot ticking along). Anyone following my Twitter posts will see that I share Steve Mirsky’s direct and spot-on comment that ‘I’m going all-in on Einstein still being right’. The results from the OPERA scientists is definitely extremely intriguing however, and they’ve been very brave to put it out for the world to see and to stand up and discuss it – who says science doesn’t do a good job at communicating?

I feel that many others have written far better commentaries and summaries than I could, so in the interests of letting you explore this for yourselves I’ve compiled here a few of what I think are the most useful resources. And as for reaching the stars on the tails of superluminal muon-neutrinos? I wouldn’t hold out hope for that. But maybe. just maybe, these ghostly particles have some properties we’ve not yet understood.

The OPERA science paper proper: Measurement of the neutrino velocity with the OPERA detector in the CNGS beam

Nice overview, commentary at Starts With a Bang: This Extraordinary Claim Requires Extraordinary Evidence

Another nice commentary at Galileo’s Pendulum: I Don’t Want to Write About Neutrinos

At Scientific American (although the title is a little too much): Particles Found to Travel Faster Than Speed of Light

At the NY Times Dennis Overbye as always provides essential perspective: Tiny Neutrinos May Have Broken Cosmic Speed Limit

At The User’s Guide to the Universe a nice sanity check: Faster Than Light Neutrinos? A Quick Calculation

Finally, once they put it up, today’s live webcast with the scientists will be available from CERN

And if your brain is still operating subluminally, there is a nice mini-doc video from CNRS here:


Faster than Light? by CNRS

Caleb A. Scharf About the Author: Caleb Scharf is the director of Columbia University's multidisciplinary Astrobiology Center. He has worked in the fields of observational cosmology, X-ray astronomy, and more recently exoplanetary science. His latest book is 'Gravity's Engines: How Bubble-Blowing Black Holes Rule Galaxies, Stars, and Life in the Cosmos', and he is working on 'The Copernicus Complex' (both from Scientific American / Farrar, Straus and Giroux.) Follow on Twitter @caleb_scharf.

The views expressed are those of the author and are not necessarily those of Scientific American.



Previous: Life in liquid carbon dioxide More
Life, Unbounded
Next: What next for neutrinos?




Rights & Permissions

Comments 36 Comments

Add Comment
  1. 1. Scienceangela 3:47 pm 09/23/2011

    I noticed that you mentioned the article in the New York times. It states that if the results of the Opera researchers turned out to be true, it could be the first hint that neutrinos can take a shortcut through space, through extra dimensions (string theory). The NYT also states that according to Joe Lykken of Fermilab, “Special relativity only holds in flat space, so if there is a warped fifth dimension, it is possible that on other slices of it, the speed of light is different.” In fact, this is quite an interesting isn’t it!

    Link to this
  2. 2. Caleb A. Scharf in reply to Caleb A. Scharf 3:57 pm 09/23/2011

    It is certainly interesting. *If* no one can find anything amiss with the experimental measurements themselves (and these are not easy) then it will definitely prompt a lot of further thought. I guess the thing nagging at the back of my mind is that if neutrinos (let’s say these higher energy ones) can indeed do this kind of dimensional skipping as hinted at in the comments for the NY Times then there must be some ‘natural’ evidence out there – i.e. physical phenomena doing some weird stuff. If so, then would these phenomena really be so dull/hidden/irrelevant that we just hadn’t noticed before?

    Link to this
  3. 3. brerlou 4:23 pm 09/23/2011

    They MUST exist, whatever you choose to call them, or whether they can be detected or not. Their existence also is strong evidence of the existence of “parallel” universes with which we can have no interaction, except at an intellectual level. The whole concept of continuous mathematics suggests that between any two points however tiny must exist an infinity of other points. Our universe is bounded, FOR US, by the nature of human perceptions, sight specifically, which depends on our ability to detect the passage of photons through space. There is no magic about this. We have simply built all our science and its math around an axiom of ZERO MASS for the photon. Concomitantly, in our science, the universe becomes infinitely dense (gross simplification) at the speed of light and no particle can travel faster than the speed of light. However, if axiomatically, we were to postulate a particle with less than what we CALL zero mass, then using axiomatic mathematics we can accommodate the theoretical existence of particles faster than light. We can also postulate a shorter route between two points than that taken by light, too, but that requires further explanation, though relevant.

    Link to this
  4. 4. Chuck Darwin 4:46 pm 09/23/2011

    I predict they will find an error in the calculation of the distance between the two labs. The neutrinos were beamed straight through the Earth, and there is no (other) way to directly measure the straight-line distance between two points on Earth that aren’t within eyesight of each other. So the distance has been calculated using some formula or reference table rather than measured precisely using a laser. This also means it in this experiment it is impossible to directly show that the neutrinos arrive before photons would arrive over the same pathway. The only way to be really certain is to repeat the experiment using a target that has the same pathway open to both photons and neutrinos.

    Link to this
  5. 5. ALFlanagan 5:18 pm 09/23/2011

    If this is true, we gain an important new technological capability. That being, that we can detect if the sun explodes seconds _before_ the radiation front turns us all into plasma. I don’t have to tell you how crucial that could be.

    Link to this
  6. 6. jtdwyer 9:36 pm 09/23/2011

    As Chuck Darwin points out, there’s no obvious way to measure the actual distance traversed by detected neutrinos. I don’t even think there’s any way to determine the actual path taken. Astronomers once presumed that light always travels in a straight line: to accommodate that view Einstein had to curve spacetime, or at least its assigned dimensional coordinates.

    Personally, I like to consider that light passing through the gravitational field of a massive object is, just like all matter within a gravitational field, accelerated in the direction of that field’s focal point.

    In this view then, light passing through a gravitational field is accelerated in the direction of that field’s focal point which, depending on the direction of that light’s self-propagation, generally curves the net direction in which that light propagates, relative to an external observer.

    Note that this does not increase the velocity of light in the direction of its self-propagation: it only adds additional velocity in the massive object’s direction. However, by changing the direction of propagation it also alters the path traversed.

    If this perspective is adopted to the propagation of neutrinos through the Earth, perhaps the additional directed velocity imparted by gravitation can reduce the total traversal time even though it may seem to increase the distance traversed.

    Of course, this conception does not agree with curvature of abstract dimensional coordinates as described in general relativity, but I prefer simple, more physical explanations…

    Link to this
  7. 7. jtdwyer 9:45 pm 09/23/2011

    Chuck Darwin – your suggestion to “repeat the experiment using a target that has the same pathway open to both photons and neutrinos” seems perfectly rational but might not produce the same results.

    It seems that propagating neutrinos oscillate between their three flavors, each with still tiny but different (assigned) masses. Moreover, that oscillation varies when neutrinos are propagated through matter. Please see:
    http://en.wikipedia.org/wiki/Neutrino_oscillation
    http://en.wikipedia.org/wiki/Mikheyev%E2%80%93Smirnov%E2%80%93Wolfenstein_effect

    Link to this
  8. 8. MarkHarrigan 9:50 pm 09/23/2011

    @Chuck Darwin – you may be right although reports show they went to extreme measures to get the distance calculation correct and the reported review by many physicists http://www.newscientist.com/article/dn20961-fasterthanlight-neutrino-claim-bolstered.html supports their approach BUT (and it is a big but I think)
    apparently there is no detection of the neutrino’s departure from CERN.

    “because there is no neutrino detector on CERN’s end of the line. The only way to know when the neutrinos left is to extrapolate from data on the blob of protons used to produce them.” according to Plunkett from Fermilab.

    That source, I gather, is a 20cm long target.

    So one possible source of the discrepancy is that the timing of the sub-atomic reaction that produces the muon-like neutrinos has been mis-measured in some way. They use a ceasium clock but if they have to inference from the reaction perhaps this might be an explanation.

    Exciting physics no matter what!

    Link to this
  9. 9. jtdwyer 10:46 pm 09/23/2011

    MarkHarrigan – The newscientist.com article seems to describe a linear distance derived from relatively precise determination of the proton source and neutrino detector locations on the Earth’s surface.

    In more straightforward terms than before, perhaps some relativistic effects (such as ‘spacetime’ curvature within the Earth) produced by the near relativistic propagation of neutrinos in conjunction with the Earth’s gravitational effects are contributing to unidentified physical conditions of neutrino traversal distance/velocity.

    The actual path taken by the neutrinos to their detection device seemingly cannot be definitively determined.

    Link to this
  10. 10. brackenbeds 7:10 am 09/24/2011

    I am sure the researchers have thought of this, but it is not mentioned in the prepress paper they released yesterday.

    Gravity actually decreases as you go down inside the earth. Newton knew this as the integral of the gravitational attraction over the shell outside your radius cancels out.

    The neutrinos travelling through the earth will be in a region of lower gravity compared to the surface. In fact its hard to calculate exactly as the outer shell is not uniform and in this case includes the alps, so gravitational anomolies will be present in the neutrino beam. They will travel 700km in a region of (slightly) reduced gravity.

    Time slows in a gravitation field and speeds up as gravity reduces so for a while the neutrinos will experience a speeding up of time (slightly) just as GPS satellites do being further away. In their frame of reference they will not exceed c.

    As the observed effect is only about 1 in ten to the 6 this is about the right order of magnitude.

    If this is correct ironically it will actually reinforce Einstein who of course produce the original equations to show how time is affected by gravity!

    Link to this
  11. 11. peterwusc 7:35 am 09/24/2011

    If ruling out any possible error in measurement, I believe the issue is the speed of light. No one has measured the speed of light through “the Earth”. While it is commonly believed the speed of light in vacuum is the highest amount all “media”, only neutrino can really travel through the Earth without much interaction. In other words, I conjecture that if someone can really send high energy X-ray through the same path and measure the speed, it may still be larger than the neutrino’s speed and larger than the speed of light in vacuum. This experiment may actually have discovered “the speed of light” in some case can be traveling faster than that in vacuum, maybe depending on medium, gravitation or any kind of reasons.

    Link to this
  12. 12. Torbjörn Larsson, OM 8:27 am 09/24/2011

    If you want one quick-and-dirty check that gets the correct discrepancy, and isn’t yet covered in the paper or discussions, it is akin to your ideas:

    According to the paper the distance measurement procedure use the geodetic distance in the ETRF2000 (ITRF2000) system as given by some standard routine. The european GPS ITRF2000 system is used for geodesy, navigation, et cetera and is conveniently based on the geode.

    I get the difference between measuring distance along an Earth radius perfect sphere (roughly the geode) and measuring the distance of travel, for neutrinos the chord through the Earth, as 22 m over 730 km. A near light speed beam would appear to arrive ~ 60 ns early, give or take.

    Of course, they have had a whole team on this for 2 years, so it is unlikely they goofed. But it is at least possible. I read the paper, and I don’t see the explicit conversion between the geodesic distance and the travel distance anywhere.

    Unfortunately the technical details of the system and the routine used to give distance from position is too much to check this quickly. But the difference is a curious coincidence with the discrepancy against well established relativity.

    Link to this
  13. 13. SAJP2000 10:57 am 09/24/2011

    Instead of gaphawing and setting yourself up for a big, comfy ‘I told ya so’, how about some decent speculation on just what they might have detected at CERN?

    Too tough eh?

    Link to this
  14. 14. jtdwyer 3:35 pm 09/24/2011

    Torbjörn Larsson, OM – Very good, as much as I could follow. In my many years of unrelated experience with large systems, large teams of subject area experts often produce intractable problems that, in many cases, only an external analyst can identify. It’s human nature…

    SAJP2000 – Why haven’t you begun, already?

    From a comment posted to another article:
    I think these researchers have simply released their observations to openly solicit comments from their peers to resolve an apparent anomaly. However, reading their report I think they are naturally convinced of the correctness of their implementation and have not really released enough detailed information about their actual programming algorithms and methodology for external contributors to identify any source of error.

    Link to this
  15. 15. Paul Duffy 11:33 pm 09/25/2011

    Is it possible that matter changes to form and speed of neutrinos. This could account for neutrinos arriving from the 1987 supernova ahead of light (accelerated by passing through matter at time of explosion) and what recently happened at CERN. Matter may spped accelerate some particles?

    Link to this
  16. 16. jtdwyer 12:38 am 09/26/2011

    Paul Duffy – Generally, not likely.
    Please see my much more complete response in the blog:
    http://blogs.scientificamerican.com/basic-space/2011/09/23/faster-than-light-neutrinos-show-science-in-action/#comment-81

    Link to this
  17. 17. jtdwyer 8:59 am 09/26/2011

    To reiterate and summarize previous comments:

    The reference speed of light Time of Flight (TOF) estimation may have used standard GPS routines to calculate (curved) surface distance.

    Whatever distance was used for the speed of light TOF reference, the actual distance traversed by detected neutrinos cannot be definitively determined. These distances are a likely source of significant error.

    If, as it seems most likely, detected neutrinos traversed a much shorter nearly linear flight path than was presumed by the speed of light TOF estimate the resulting distance discrepancy may account for the apparent FTL neutrino velocity.

    Distance assumptions should be carefully examined for potential errors!

    Link to this
  18. 18. hdchiba 4:14 pm 09/27/2011

    heavier objects (e.g., our sun) according to standard theory “warp space” & light bends. light bending says that light’s direction is changed by existing conditions. could gravity also speed up or hinder light? a “black hole” slows down radiation (including light) to the extent that nothing escapes its grip. so, if radiation (=light) can be slowed it can also be accelerated.

    Link to this
  19. 19. jtdwyer 4:40 pm 09/27/2011

    hdchiba – I know little about it, but as I understand an object of mass travelling at near the speed of light should linearly contract local spacetime.

    As in the astronaut traveling at near the speed of light for a couple of years and returning to Earth thousands of years later, it seems to me that a non-zero mass particle travelling through ~730km of spacetime (within the Earth’s local spacetime) should see some effect – perhaps a few dozen nanoseconds? But then, I don’t do math and don’t know about relativity…

    Not to mention that zero rest-mass light has been observed to curve by the gravitational effects of the Sun – IMO it could be considered that the light is accelerated in the direction of the Sun’s point-mass. I don’t think there has been any experimental measurement of gravitation’s effect on the speed of light.

    However gravitation might effect light, it would seem that it would affect non-zero mass neutrinos even more…

    Link to this
  20. 20. Dr. Strangelove 9:49 pm 09/27/2011

    I wonder if they know the mass of muon neutrinos with great accuracy. The path of neutrinos is curved because of earth’s gravity. If the neutrinos have less mass than expected, the curvature would less and the path/distance travelled is also shorter. It would appear they are travelling faster than light since they can cross the path at a shorter time then expected.

    I don’t know if the uncertainty in the mass of neutrinos can explain the discrepancy between the expected time and the observed shorter time.

    Link to this
  21. 21. sureshkumar 4:57 am 09/28/2011

    So far, none of the known and confirmed experiments have cast any doubts on foundations of special relativity (SR),even if the superluminal neutrinos do exist,and that is a big if,since the recent report about the discovery of neutrinos superluminal propagation in the CERN OPERA experiment may be based due to some subtle error;it could be another case of observed superluminal group velocity-possible because the earth’s crust acts as an optical medium with refraction index close but not exactly equal to 1 for neutrinos and thus can reshape the pulse
    Also,this discovery will not necessarily call for revision of the existing theory,even if confirmed and proved to be not due to any systematic error in measurement.
    For your information,Einstein`s SR [special relativity]SR in no way forbids superluminal motions.
    For instance,The mathematical structure of SR explicitly admits the existence of superluminal particles – tachyons. In fact symmetry becomes more complete if each known particle may have its superluminal“dual” partner.
    It seems unlikely that any, constant could restrict the domain of SR,and it is least likely that it could be the same constant c,speed of light.
    May be it is possible that there is some kind of an energy threshold with particle energies of a certain order[say 10^18 ergs or so,since that coresponds to Planck`s length],As the particle energies approaches this limit a part of the energy is transferred to space-time fabric,and at or beyond this threshold,for relativistic particle energy limits,there is a stretch of the space time fabric.
    As a result of this the velocity of the particle appears to the observer to have increased since it it coves additional distance in that time,due to the expanded space.
    In short dark energy like effects are being produced in the particle domain
    Prof Sureshkumar.s,Chief scientist,CSIR-NIIST,TRIVANDRUM,INDIA

    Link to this
  22. 22. Rene Dupont 3:44 pm 10/2/2011

    Could it be that it is not Neutrinos but the wave function that takes a shortcut?
    Quantum-mechanically, all we measure of a process are the particle bunches at the entrance of the beam line and the product particles in the detectors.
    Electrical insulation and radiation protection along with the detectors delimit a Black Box and we do not know what happens inside.
    For example, a process (e+,e-) to (Neutrino (N), Antineutrino (N’)) with two colliding beams can either produce a real collision and, after intermediate stages with real particles end up sending out Neutrinos.
    Or, the two beams can choose not to collide at all but to produce only a virtual collision with virtual intermediate stages and produce the Neutrino directly in the detector.
    This direct Neutrino production is due to interference of the wavefunctions of the two beams. The wavefunctions extend at the speed of light through all of space.
    In order to make clear the short cut, consider that for a straight beam line, the two beam entrance detectors and the final Neutrino detector constitute a triangle. (I can’t draw that here, unfortunately) The Neutrino event can occur as soon as light rays (the wavefunction) from the location of the two beam entrance detectors (the entrance limits of the black box) upon beam passage reach the N-detector in straight lines.
    These straight lines are of course shorter than the imagined path: entrance to collision and collision to N-detector.
    The seeming superluminal velocity comes about since we think that the beams had continued at the speed of light and then emitted Neutrinos which, of course, need to go quickly to not miss the rendez-vous in the N-detector.
    The superluminal effect is strongest for the detector placed normal to the beam line. It is weakest or disappears when it is placed in the beam axis.
    For geometrical reasons again, time lag will not depend much on distance – beam to N-detector- but rather on the placement of the beam entrance measurements since they determine the baseline of the Black Box triangle.

    Link to this
  23. 23. jtdwyer 4:08 pm 10/3/2011

    Based on charts illustrating the numbers of proton and neutrino detections (see Fig. 11 in the official OPERA report: http://arxiv.org/ftp/arxiv/papers/1109/1109.4897.pdf ) indicating, in particular, a destabilization of proton and neutrino beam conditions occurring following a peak in detections ~6,000 ns for first extractions and about ~7,000 ns into each extraction run, I strongly recommend that only data representing stable beam conditions prior to those peaks be selected for reanalysis.

    In more detailed reports the effects of destabilization are referred to as ‘oscillations’ which are excluded or filtered (‘smoothed’) in the proton detection data only. No adjustment is made for the neutrino detection data, which may also be skewed by what may be a harmonic resonance occurring within the proton and resulting neutrino beams.

    If final neutrino ToF results produced from selected stable beam data substantially contradicts the analysis of the complete set of extraction duration data, especially if the stable beam data does NOT indicate FTL neutrino flight times, the current FTL conclusion would have to be reconsidered as a product of beam conditions.

    If the subset of stable beam data confirmed the FTL conclusion it would be to some extent substantiated.

    Since this approach does not require any additional experiments, it can be undertaken by selecting data and reanalyzing results.

    Link to this
  24. 24. Verwonderaar 3:12 pm 10/4/2011

    I think it is not possible to select a subset of the data to determine the TOF. The detected events of the entire burst of 10.5 us must be used and the rising and falling edge of it are probably of most relevance in statistically determining the TOF. I agree however that the beam stability is the one which may be responsible for the the observed anomaly. Could it be that the beam direction (which is said to be controlled, with 50m accuracy arriving at San Grasso) is not stable yet at the rising edge of the neutrino burst? If the beam is mis-directed at the start of the burst, this would reduce the probability of detecting a neutrino detection in the first half of the 10.5 us burst (and would lead to a measured TOF smaller than based on speed of light. The beam is said to have a footprint of 750m at San Grasso (with 50m pointing accuracy), and the detector size I estimate at about 20m diameter. 50m at 730000m is about 0.004 degrees (a real challenge!). Perhaps the beam pointing is off (unstable) when the burst commences. I could not find any reference in the article on the pointing stability of the beam. In my view the measurements of distance and time are the least suspect, and so is Einstein for the time being. The measurement is based on statistics of very rare events during bursts of 10500 ns, probably with a 60 ns systematic error. A slight imbalance in neutrino density in the first 5250 ns relative to the second 5250 ns of the burst (and particularly during the rising edge) could cause a bias in the derived TOF. Un-accounted beam pointing instability could perhaps be one of the reasons. How do they control pointing this beam with a precision better than 0.004 degrees?

    Link to this
  25. 25. jtdwyer 4:48 pm 10/4/2011

    Verwonderaar – Thanks very much for your consideration!

    I may be wrong, but I take the charts to represent the sequence of all 10.5 us burst samples collected. If that is correct, I’m not suggesting truncating any bursts, but selecting a range of samples for analysis.

    I relied on a large but clearly written 182 page thesis by Giulia Brunetti, which can be found at:
    http://operaweb.lngs.infn.it:2080/Opera/ptb/theses/theses/Brunetti-Giulia_phdthesis.pdf

    Beam alignment is discussed in section 3.2, “CNGS-OPERA Alignment”.

    I had to abandon any attempt to identify any specirfic error in the exceeding complex equipment and procedures and simply focus on the results. Whatever the cause, I conclude that some instability was introduced as the number of extractions performed progressed. This occurred in both 2009 and 2010, as shown in Fig. 8.4 of the Brunetti thesis and described in section 8.1, “OPERA Events and Data at CERN”.

    Link to this
  26. 26. jtdwyer 10:29 pm 10/4/2011

    Verwonderaar – Thanks for pointing out my error – I had lost sight of the data treatment. As I now understand, you are correct, the referenced charts do represent a representative distribution of protons released and neutrinos detected for each extraction burst.

    If I understand reasonably well, the distributions of events are used to probabilistically assign a propagation start time for detected neutrinos in the determination of approximate Time of Flight.

    To exclude the detected neutrinos that may have been affected by the proposed beam instability without effecting the ToF approximation methodology, I suggest that after ToF has been estimated for neutrinos, that their detection time be used to exclude detections that occurred after the proposed burst destabilization event.

    I hope this suggestion is comprehensible. In summary, I suggest that a beam destabilization event occurs during all particle extraction bursts and propose that timed neutrino detections be excluded from the analysis summation.

    Please let me know if I’ve misstated anything or not stated anything clearly enough to understand – thanks again!

    Link to this
  27. 27. Jose_X 9:55 pm 10/16/2011

    [I posted this comment below recently elsewhere.. after a rebuttal paper was published claiming relativistic length contraction was not factored in. The main point below is a guess/hunch that it's reasonable that perhaps the syncing of clocks via GPS might have become desync'd at the time of experiment measurements because of variable instrument delays in digital electronics.]

    I read over the rebuttal paper and it appears to be incompatible with what I read on the primary paper (I am not a physicist, btw), so I agree with this article. Namely, the original states that “common-view” was used to sync the earth clocks used to measure the neutrino events. The rebuttal states clearly, “the clocks in the OPERA experiment are orbiting the earth in GPS satellites”.

    A comment above I think calculated that the satellites go slow enough and are near enough to us that errors would be much smaller than what was calculated. This would agree with the likely 1ns max suggested error for the common-view method.

    Not having looked much further, I think the delay times for the instrumentation might be off, or, more specifically, there are hidden delays not accounted for ..OR, the syncing was done with a different set of delays as the actual experiments.

    If this sort of experiment has not been done to this resolution before, such high precision errors would not have showed up. When the group got the upgrade to newer GPS interface in 2008, it’s possible some assumption from the era of the earlier instrumentation design were not re-visited.

    One clue is that I notice the orig paper mentions FPGA delay values. That seems rather specific. Are they ignoring other digital logic delays.. example, some processing board logic or not-real time software system that manipulates those values? Maybe during syncing a different algorithm and hence time to produce results takes place vs during the experiment. There might even be variable values or some part of the system has not warmed up to operating temp and speed (or there are cache issues, etc).

    If the instrument delay during the experiment in CERN is shorter than used to sync there (the neutrinos “false start” the race relative to expectations at LNGS) or if the instrument delay during experiment measurement in LNGS is longer than during timing sync (we start the LNGS clock too slow relative to the expectations at CERN), we would get the bias in the direction of shorter computed travel time (and hence faster implied speed).

    Notice that most of these flaws are probably not with the theory of measurement or the physics. Whoever put together the hardware, to the extent it is software based and may have been changed after installation, may have not updated their side of the timing model properly (or the sw/hw was never properly analyzed.. at least not under the implied tighter post 2008 requirements). Were COTS components used and/or changed recently?

    Link to this
  28. 28. Jose_X 10:08 pm 10/16/2011

    I can reduce the size of the prior comment a bit:

    I would think it’s possible to sync using one set of instrument delays and then do the measurements with a different delay. This would explain data that appears to show too fast neutrinos (or too slow).

    Why might the different delays exist? There are many possibilities, but we should note that digital electronics frequently have a sw component that might have been changed recently without proper analysis of the time issues of the algorithms. In fact, I think the paper mentions an upgrade in the GPS sync hardware in 2008. These new tighter time constraint assumptions might not have led to a re-evaluation if the timing assumptions/requirements in the rest of the system.

    For apparatus recently upgraded and performing measurements at precision levels never attempted before, we can easily see how an instrument design assumption error might sneak in (even more likely if COTS hardware with custom sw forms part of the system).

    Link to this
  29. 29. jtdwyer 3:35 pm 10/17/2011

    Jose_x – as I understand from http://operaweb.lngs.infn.it:2080/Opera/ptb/theses/theses/Brunetti-Giulia_phdthesis.pdf the GPS software used was some international standard used for many purposes but I think not for measuring relativistic velocities over a GPS derived distance. While I think the distance was determined by the ‘shortest path’ between the two specified points, I also suspect that at relativistic velocities some linear contraction of spacetime might occur, affecting actual distance traversed. However, I’m just guessing…

    Link to this
  30. 30. Gord Davison 2:59 pm 10/25/2011

    Perhaps the neutrinos are tunnelling though other dimensions and moving through another axis seemingly traveling faster than light. They are not moving the distance that we think they are. This velocity of the neutrinos does not disprove any of Einstein’s equations. It simply means we have a square root of -1 (imaginary operator) in them. Usually if this happens in an equation then it points to there being another axis available.

    Also the speed of light is based on, well light, which is made up of photons. That speed is measured in against a backdrop of what we think of as the dimensions of space. So the velocity of light is measured by the distance that a photon will travel per unit of time. That definition of it points to the dimensions used to define it. Considering that there are six other dimensions that we have not really been able to observe, perhaps the neutrinos are traveling partially through some of those?

    The speed of light is calculated from Eo, the strength of the electrostatic force and the u, the strength of the magnetic interaction. Eo is 8.854187817 x 10^12 coul^2 / (joule-meter) and u is 4 x pi x 10^-7 N / amp^2. The speed of light, c = 1/(E0 x u)^0.5. What this demonstrates is that the speed of light in the space that we are used to describing is limited because of the dielectric of space itself. Space, or how we perceive it, is a result of photons traveling through it and the speed limit, c, is a result of that observation. When there is no space measured in meters and velocity in meters/second then the speed of light becomes meaningless. The other dimensions are not dimensions of space but of different kinds of forces.

    Link to this
  31. 31. jtdwyer 7:55 pm 10/25/2011

    Gord Davison – You stated:
    “Considering that there are six other dimensions that we have not really been able to observe…”

    Pray, tell more of these other dimensions, how they were discovered and the evidence of their physical existence!

    Link to this
  32. 32. BertMorrien 5:45 am 11/14/2011

    About “Measurement of the neutrino velocity with the OPERA detector in the CNGS beam”
    ( http://static.arxiv.org/pdf/1109.4897.pdf )

    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.
    Due to the summing of the PEWs, OPERA used almost entirely PEW parts without a corresponding event.
    The PDF would be valid only if all parts of all PEWs had a corresponding event.
    As it is, only one in 10,000 parts of the PDF has a corresponding event, which makes it invalid.
    The current analysis allows the parts without a corresponding event to determine the shape of the PDF; it cannot be ruled out that this results in bias.
    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.
    If this is the mainstream view, it explains why the analysis is taken for granted and then I am wondering what to think about that.

    Ironically, there is a very simple way to exclude the PEW parts without corresponding event.
    Currently the PEWs are summed while the start of the PEWs are still aligned with the kicker magnet signal.
    It is also possible to time-shift the PEWs, so that the corresponding events are aligned; in that case the parts of the PEW with a corresponding event are aligned as well.
    If the PEWs are summed now and a scan is done over the obtained sums, it can be shown that a single maximum will indicate the start time.

    Bert Morrien,
    Eemnes, The Netherlands

    Link to this
  33. 33. BertMorrien 6:13 am 11/20/2011

    The newest outcome of Opera’s neutrino velocity measurement included also the result of an alternative analysis.
    This result was compatible with the earlier finding, and so was the result of a new experiment with much shorter pulses.
    This means, Opera’s current analysis must be valid.
    This means also that Opera knew exactly what they were doing.
    Consequently, the PDF obtained by summing the PEWs is valid, despite the lack of PEW parts with a corresponding event.
    This is because with enough events, the event distribution resembles the shape of the PDF sufficiently for trusting the outcome of a maximum likelihood analysis.
    It is regrettable that this point never became clear to me before.

    The lesson learned is that declaring the PDF and Opera’s analysis invalid is a good example of narrow minded reasoning; a humble apology is in order here.

    Bert

    Link to this
  34. 34. jtdwyer 2:14 am 11/23/2011

    Bert Morrien: You, I and the many OPERA Collaboration team members who correctly argued for the retest allowing 3 ns precision measurement of proton detection prior to neutrino emission were all proved wrong. I certainly expected the revised test to provide contradictory results. However, that retest was necessary to determine the correctness of the original statistical methods. Those methods had certainly allowed for a potential error far exceeding the identified 60 ns discrepancy. Good job!

    Link to this
  35. 35. BertMorrien 2:24 pm 11/24/2011

    jtdwyer:
    Thanks.
    When scrutinizing the original OPERA report, I almost immediately saw an alternative analysis method. Only afterwards I started to doubt the original analysis, not because of the long pulse but I realised the dull PDF shape combined with possible uneven spreading of the Poisson event distribution could cause a shift of the point of maximum likelihood. See also
    http://www.science20.com/comments/88966/SaschaOK_fair_enough_It

    Link to this
  36. 36. hab_kab 12:32 am 02/14/2012

    Hi,
    I am Hamid Reza karimi,my paper by title “Explaining how and why the muon neutrinos flow faster than the
    speed of light in the OPERA neutrino Experiment”was published on vixra eprint:http://vixra.org/abs/1201.0005
    This article gives answer to the four following questions about the opera experiment
    1 – Why do neutrinos flow faster than speed of light but the electron doesn’t.
    2 – Why there is no deformity in energy of the neutrinos .
    3 – Why does not cosmic neutrinos break the speed of light.
    4 – In which area The laws of relativity are true.
    Best regards,

    Link to this

Add a Comment
You must sign in or register as a ScientificAmerican.com member to submit a comment.

More from Scientific American

Scientific American Back To School

Back to School Sale!

12 Digital Issues + 4 Years of Archive Access just $19.99

Order Now >

X

Email this Article

X