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CERN Experiment Indicates Faster-Than-Light Neutrinos 1088

Posted by timothy
from the they're-ahead-of-their-time dept.
intellitech writes "Puzzling results from Cern, home of the LHC, have confounded physicists — because it appears subatomic particles have exceeded the speed of light. Neutrinos sent through the ground from Cern toward the Gran Sasso laboratory 732km away seemed to show up a few billionths of a second early. The results will soon be online to draw closer scrutiny to a result that, if true, would upend a century of physics. The lab's research director called it 'an apparently unbelievable result.'" Also on the AP wire, as carried by PhysOrg, which similarly emphasizes that the data are preliminary. Update: 09/22 20:43 GMT by T : Reader Curunir_wolf adds a link to the experiment itself, the Oscillation Project with Emulsion-tRacking Apparatus, or OPERA, which "was developed to study the phenomenon of neutrino transmutation (neutrinos changing from one type to another. The speed of the neutrinos, of course, was an entirely unexpected observation."
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CERN Experiment Indicates Faster-Than-Light Neutrinos

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  • by elrous0 (869638) * on Thursday September 22, 2011 @03:24PM (#37483320)

    EOM

    • by bre_dnd (686663) on Thursday September 22, 2011 @03:30PM (#37483388)
      It may still be a consistent measurement fault, but they've repeated it 15000 times. FTFA: "The team measured the travel times of neutrino bunches some 15,000 times, and have reached a level of statistical significance that in scientific circles would count as a formal discovery."
      • by icebike (68054) on Thursday September 22, 2011 @03:36PM (#37483460)

        Regardless of how many times you repeat a measurement with a faulty ruler, the measurements are still wrong.

        How precisely did they measure the 732km?

        • by Anonymous Coward on Thursday September 22, 2011 @03:48PM (#37483624)

          They must have overlooked this point. Usually only senior/nobel level reasearchers can understand the extremely complicated system of faulty rulers and suspicious measurement results. In my experience, turning the thing OFF and ON again, would have done it.

        • by Lisandro (799651) on Thursday September 22, 2011 @03:50PM (#37483674)

          How precisely did they measure the 732km?

          Why, by closely watching oxens plough [wikipedia.org]!

        • by Cyberax (705495)

          With commercial prospector-grade GPS hardware one already can get sub-centimeter precision.

          If they used things like laser-ranging satellites then sub-millimeter precision is quite easy to achieve (that's how we can view the continental drift in real time).

        • by OverTheGeicoE (1743174) on Thursday September 22, 2011 @03:58PM (#37483780) Journal

          According to the ABC article, the particles are showing up 60ns too early. If the particles were in fact traveling at light speed, that would simply mean the detector was about 18 meters closer to CERN than they originally thought. Considering differences in altitude, oblateness of the Earth, the detector is underground, and so on, it isn't hard to imagine an 18m position error over approximately 732,000 m distance measured or calculated.

          • by Liquidrage (640463) on Thursday September 22, 2011 @04:04PM (#37483860)
            So you're saying there's an 18m wormhole that makes these things get there "faster" than light. Or that they aren't capable of measuring to within 18 meters at that scale? I'd say that isn't very likely and I'd have a hard time imagining it. What I could imagine is that there's a mistake somewhere or equipment issue possibly. But repeated 15k times, and I fully trust the people at CERN OPERA to measure within 18m.
            • What's the alternative? the knowledge that is the cornerstone of modern physics, knowledge that has been tested time and time again and found true, is upturned by one experiment? Sorry, my money's on a measurement error.
              • by Toonol (1057698) on Thursday September 22, 2011 @04:49PM (#37484434)
                Of course, but these aren't crackpots screaming that modern physics is wrong. They're getting puzzling results, even after doublechecking, so they're asking others to verify. This is the by-the-book scientific process.
              • by shutdown -p now (807394) on Thursday September 22, 2011 @05:37PM (#37485068) Journal

                the knowledge that is the cornerstone of modern physics, knowledge that has been tested time and time again and found true, is upturned by one experiment?

                Well, it's not like it never happened before...

                If their finding is correct, it doesn't mean that previous experiments were wrong. It just means that things are more complicated than we thought them to be. It's a darker side of the Occam's Razor - you get rid of unnecessary things, sure, but how do you determine whether they are unnecessary? why, based on your experimental input - you need the simplest model that can explain the results that you see, and predict future results when you test it. Problem is, your experiments might not be covering some edge case, and therefore you didn't see the complete picture - and oversimplified your theory.

              • by Savantissimo (893682) on Friday September 23, 2011 @03:24AM (#37488580) Journal

                "What's the alternative?"

                The alternative is not that Einstein was wrong, but that neutrinos have imaginary mass rather than real mass. This is consistent with observations. We can't measure neutrino mass in experiments, only mass squared, and the error bars on those measurements persistently include some small negative numbers. (And some of these measurements virtually exclude any positive mass^2 values. Other measurements purporting to exclude negative mass^2 values may be the result of over-correction and wishful thinking.)

                Imaginary-mass particles are consistent with relativity and were first theorized in the 1960s and given the name "tachyons". High-energy tachyons move near the speed of light; low-energy tachyons move at unlimited velocities. This accounts for the fact that the neutrinos from the 1987A supernova were only 18 hours ahead of the light from the explosion, despite the distance -- they were extremely high energy tachyons.

                If neutrinos are tachyons, this could account for a couple of odd things about them - the exceptionally low cross section (likelihood of interaction) and their oscillating between different flavors (electron, muon, tau). Exactly how is a job for the theoreticians, but it seems to me that a neutral particle moving effectively backward in time and at unlimited velocities coupled with low energies is not often going to interact, and imaginary mass could be likened to a rotation or oscillation, much like many other things involving imaginary numbers in physics.

                Physicist John Cramer talked about the idea back in 1992 in his Analog column: Neutrino Physics: Curiouser and Curiouser (Alternate View Column AV-54) [washington.edu]

                of the six most recent experimental determinations of neutrino mass, all have given negative values of the mass-squared to within the statics of the measurements. The experimental observation is that in the vicinity of the end point the yield of electrons lies above the zero-mass line, while for neutrinos with non-zero real mass, the electron yield should lie below this line. The measured mass-squared values are negative to an accuracy of several standard deviations in the most recent of these experiments.

                These experimenters have been strangely quiet about mass-squared measurements with negative values. If the results had been positive by the same amount, the literature would be filled with claims that a non-zero value for the neutrino mass had been established. But a negative mass-squared is not something that can be easily publicized.

                You obtain the measured mass value from a mass-squared measurement by taking the square root of the measured value. However, the square root of a negative number is an imaginary number. Thus the measurements could, in principle, be taken as an indication that the electron neutrino has an imaginary mass.

                What are the physical implications of a particle with an imaginary rest mass? Gerald Feinberg of Columbia University has suggested hypothetical imaginary-mass particles which he has christened "tachyons". Tachyons are particles that always travel at velocities greater than the speed of light. Instead of speeding up when they are given more kinetic energy, they slow down so that their speed moves closer to the velocity of light from the high side as they become more energetic. Feinberg argued that since there are no physical laws forbidding the existence of tachyons, they may well exist and should be looked for.

                Here's a link to another, slightly more technical look at the idea: Neutrinos Must be Tachyons [arxiv.org] by Eue Jin Jeong. Googling "neutrino tachyon" also turns up several previous discussions.

          • by ATestR (1060586) on Thursday September 22, 2011 @04:10PM (#37483936) Homepage

            I seriously doubt that they would have an 18 meter bust, even if they were surveying using 1950's surveying equipment. Errors that creep in using simple trigonometry are on the order of 1:100,000. GPS is a whole lot more accurate.

          • Considering differences in altitude, oblateness of the Earth, the detector is underground, and so on, it isn't hard to imagine an 18m position error over approximately 732,000 m distance measured or calculated.

            Considering that the world's longest tunnel is 57 km long and they drilled it from both ends and the error when both ends met in the middle was about a half meter, one gets an idea of what's the attainable precision.

            If they used the same level of precision, scaling up the error would result in a 6 m error at 732 km. However one must take into account that in digging the railroad tunnel they only went to the precision level they needed for that job, one must assume that the scientists used more precise metho

          • by jambox (1015589) on Thursday September 22, 2011 @05:40PM (#37485106)
            But, if they can send light down the same route and get the same result, then they can show a significant difference between the speed of it and neutrinos.
    • by MozeeToby (1163751) on Thursday September 22, 2011 @03:32PM (#37483414)

      No kidding, extraordinary claims require extraordinary evidence, and this is one mother of an extraordinary claim. Unlike most "fast than c" research that the media distorts, it actually sounds like it would be possible to transmit information using this effect, which essentially upends either relativity or causality. But, these aren't just some cranks doing experiments in their basements, and they are appropriately guarding their choice of words to emphasis the preliminary nature of the research which is a good sign. Hopefully the experiment wasn't too expensive and difficult to perform so we can get some people started on replicated (or refuting) the results.

      • by optymizer (1944916) on Thursday September 22, 2011 @03:36PM (#37483458)
        Hold on, I just need to wipe the dust off of this LHC I keep in my garage and then we can try to replicate their findings.
        • Re: (Score:3, Funny)

          by maxwell demon (590494)

          Hold on, I just need to wipe the dust off of this LHC I keep in my garage and then we can try to replicate their findings.

          Be careful with that dust. It may still contain some dangerous microscopic black holes from your last run. :-)

        • by MozeeToby (1163751) on Thursday September 22, 2011 @03:43PM (#37483542)

          Fermilab has a similar setup which should be able to test the results. So does an experiment in Japan, T2K, but they aren't running at the moment because of the tsunami. The actual experiment shouldn't be too hard to do if you have the equipment to make a beam of neutrinos, just point them at a detector and fire away and see how long time of flight was, which means they could probably start working on it fairly soon, though it will probably take months or years to get enough data points to be statistically significant.

        • by Isarian (929683)

          Hold on, I just need to wipe the dust off of this LHC I keep in my garage and then we can try to replicate their findings.

          The bean counters told me we literally could not afford to buy an LHC for seven dollars, much less seventy million. Bought it anyway. And guess what? LHC dust is PURE POISON.

      • Re: (Score:3, Interesting)

        by JordanL (886154)
        Bell's Theorem demands that either LHV or Realism (or both) are false assumptions. Physics was presented with evidence of the lack of causality almost 40 years ago, it's just that until now we haven't had any real evidence.

        If this is a confirmed finding... we may have just proven that Realism is not a constant assumption of our Universe, which would make the Scientific Method itself a tool with limited but useful application. Or rather, it would prove that there are discoveries in our Universe that can b
        • by radtea (464814)

          Or rather, it would prove that there are discoveries in our Universe that can be made that are impossible to arrive at via the Scientific Method.

          How, exactly?

          I'm not sure what you mean by the "scientific method", but science is nothing but the discipline of testing ideas by systematic observation and controlled experiment. As a discipline it has unlimited applicability, and insofar as anything can be known, it can be known scientifically.

          What you are saying is gibberish.

      • by hedwards (940851)

        They aren't claiming that the results are correct. They're claiming that they have yet to find the error. And the article I read made it very clear that the scientists expect there to be some type of error or effect involved that explains the result, without having to have neutrinos breaking the speed of light.

        They've retested the experiment and tried various ways of finding the error and have as of now unsuccessful in finding it. So, they're kicking it to the broader community to explain. It is certainly p

    • Fuck that noise, I'm gonna get me a neutrino-drive spaceship, next stop is the Horsehead Nebula!

  • by JetScootr (319545) on Thursday September 22, 2011 @03:31PM (#37483406) Journal
    I searched for 'faster than light' on the CERN website, got articles posted in 2012, 2014. They put this new discovery to work right away!
  • Yay BBC News! (Score:5, Insightful)

    by il1019 (1068892) on Thursday September 22, 2011 @03:34PM (#37483434)
    This was a rational piece without too many sensationalist remarks! How do we show them we appreciate decent scientific writing as opposed to the crap we normally get?
  • Not so fast... (Score:3, Interesting)

    by Freddybear (1805256) on Thursday September 22, 2011 @03:44PM (#37483562)

    http://motls.blogspot.com/2011/09/italian-out-of-tune-superluminal.html [blogspot.com]

    "...the neutrinos are claimed to have arrived 60 nanoseconds before the light. Because this is claimed to be a 6-sigma signal, their total error margin of the timing should be 10 nanoseconds (3 meters over c); recall that the distance is 732 km. I leave it to the reader to decide whether this accuracy is plausible given the messy birth and detection of the particles. One nanosecond is the duration of one cycle of your iPhone microprocessor, among other things. Ten nanoseconds is 40% of the lifetime of the charged pion or 80% of the lifetime of the charged kaon. I can kind of imagine that they're doing something really silly, like imagining that each pion or kaon lives at least for the lifetime and then it dies. But some of them decay immediately; this error could erase most of the 60-nanosecond discrepancy."

    • Seems to be all he does on that blog. Find things he disagrees with, and accuses the researchers of making mistakes. Hence the 100 posts proceeding this one criticizing climate scientists, even though he's not qualified.
    • Re:Not so fast... (Score:5, Interesting)

      by epine (68316) on Thursday September 22, 2011 @04:46PM (#37484396)

      To me a nanosecond seems pretty big. I've spent a chunk of my time over the last couple of years designing consumer circuits sensitive to changes of 10ps in signal arrival time due to changes in the surrounding bulk dielectric.

      You haven't lived until you've read a datasheet with the performance spec:

      Deterministic jitter: 300 fs.

      Probably a PECL part, but still.

      And no, they're not using an instantaneous tau to approximate a decay distribution. Anyone who has ever cooked popcorn knows better than that.

      • by ChinggisK (1133009) on Thursday September 22, 2011 @05:51PM (#37485218)

        And no, they're not using an instantaneous tau to approximate a decay distribution. Anyone who has ever cooked popcorn knows better than that.

        Completely wrong. I've cooked popcorn and I have no idea what "instantaneous tau to approximate a decay distribution" means.

  • by thephydes (727739) on Thursday September 22, 2011 @03:48PM (#37483618)
    There was a young lady named bright : who could travel much faster than light : She went out one day : in a relative way: and came back the previous night.
  • by jythie (914043) on Thursday September 22, 2011 @03:49PM (#37483634)
    Eh, this happens every few years... what tends to be the case is someone gets a hold of one of the charts where velocities were recorded and due to measurement issues there is a probability curve rather then a simple line... normally you use the curve to determine what the actual velocity was, but you always get at least a couple yahoos that look at the curve, notice that one of the tails goes above C and get all excited that something is going faster then light.
    • Re:distribution (Score:5, Informative)

      by coolmadsi (823103) on Thursday September 22, 2011 @04:17PM (#37484020) Homepage Journal

      Eh, this happens every few years... what tends to be the case is someone gets a hold of one of the charts where velocities were recorded and due to measurement issues there is a probability curve rather then a simple line... normally you use the curve to determine what the actual velocity was, but you always get at least a couple yahoos that look at the curve, notice that one of the tails goes above C and get all excited that something is going faster then light.

      Good thing they are are going to put the findings online to be checked then (they have been looking for errors and have been unable to find any so far).

      The result - which threatens to upend a century of physics - will be put online for scrutiny by other scientists.

      In the meantime, the group says it is being very cautious about its claims.

      "We tried to find all possible explanations for this," said report author Antonio Ereditato of the Opera collaboration.

      "We wanted to find a mistake - trivial mistakes, more complicated mistakes, or nasty effects - and we didn't," he told BBC News.

      "When you don't find anything, then you say 'Well, now I'm forced to go out and ask the community to scrutinise this.'"

      Source: http://www.bbc.co.uk/news/science-environment-15017484 [bbc.co.uk]

  • What speed? (Score:5, Insightful)

    by jeti (105266) on Thursday September 22, 2011 @03:53PM (#37483720) Homepage

    Was it faster than the speed of light in the given medium or faster than the speed of light in vacuum?

    • by jeti (105266)

      The paper [arxiv.org] itself is now available and it confirms that the relevant speed is the speed of light in vacuum.

      PS: If I had mod points, I'd upvote damas reply.

    • by MichaelCrawford (610140) on Friday September 23, 2011 @08:39AM (#37489986) Homepage Journal

      I am intimately familiar with the interaction of light with matter as a result of having been an avid Amateur Telescope Maker [geometricvisions.com] and Amateur Astronomer since the tender age of twelve.

      This led to my acceptance to study Astronomy at Caltech in the Fall of 1982, where I was privileged to attend a non-credit class called "Physics X" that was taught by The Immortal Richard Feynman. You could ask him any question you wanted - it didn't have to be about Physics even - but the ensuing discussion had to be purely conceptual. Questions that would require Feynmen to work out equations on the chalkboard were not permitted.

      One afternoon I pointed out to him that the phenomenon that light slows down as it passes through a medium just had to be wrong. When one examines any medium at a subatomic scale, it is mostly empty vacuum with some rare particles that have all been either proven or are suspected to be geometric points. (While Protons and Neutrons have a non-zero diameter, they are each composed of three quarks, which themselves are thought to be point particles.)

      "Surely," I pointed out to Feynman, "When light passes through all this vacuous space inside a piece of glass, it always travels at precisely C! How could Snell's Law" - which yields the angle of refraction when light passes through the surface of a medium - "possibly be correct!"

      I knew damn well that Snell's Law was correct, as Snell himself experimentally demonstrated the law hundreds of years ago. While he did not measure what the Speed of Light had to do with refraction, we have been able to measure light's speed for over a century.

      Feynman replied that when light passes through matter, the charged particles in that matter oscillate in sympathy with the oscillations of the light's electomagnetic field. But because they are all in a bound state, and because accellerating charged particles causes them to emit light of their own, thereby carrying away energy and so dampening their sympathetic oscillation, the movements of the charged particles in matter is not quite in phase with the waves in the light passing through the medium.

      Feynman concluded, "The light emitted by the charge particles in matter interferes with the light passing through the medium" - that is, wave peaks add to wave peaks, and so with troughs, while peaks and troughs together cancel each other - "so that the resulting combination of light waves only appears to move slower than C."

      Thus the Photons are always moving at a constant velocity of C, but all the Photons in the medium interact so that passing a Photon through the medium will result in the exit Photon being delayed from the timing you would expect from when the entrance Photon entered the front surface. They key to understanding all this is that the entrance and exit Photons are NOT THE SAME PHOTON!

      Feynman discusses this in a really lucid way, with rigorous mathematics, in Volume II of The Feynman Lectures on Physics. Volume II covers Electricity and Magnetism, Volume I covers Classical Mechanics - Newton's Laws of Motion and such - while the third volume does Quantum Mechanics. The set of three is expensive but are easy to read, even if you don't know much Calculus, and would be a good investment for any Slashdotter.

      I was mortally embarrased to realize years later that I had asked Feynman a really basic, purely conceptual question whose completely rigorous answer led to him sharing the 1965 Nobel Prize with Tomanaga of Japan! Their Quantum Electrodynamics describes the interaction of light with electric charge with complete precision.

      Feynman's formulation uses a conceptual drawing called a Feynman Diagram as a calculational and explanatory device. I don't know how Tomanaga formulated his Quantum Electrodynamics, but my understanding as that at first no one could understand why the two theories seemed quite different but always yielded the same numerical results. Some time later Freeman Dyson - Esth

  • by hort_wort (1401963) on Thursday September 22, 2011 @03:54PM (#37483736)

    Neutrinos have been observed coming from supernovae from light years away. There would have been a very noticeable time difference between the neutrinos and the light at that distance if this were true. (Any astrophysicists about to verify this?)

    I'm skeptical. I think it was likely a wiring problem. It only takes a few centimeters of wire to make a 60ns delay, and these experiments are notorious for using many wires.

    • by radtea (464814) on Thursday September 22, 2011 @04:30PM (#37484194)

      Neutrinos have been observed coming from supernovae from light years away. There would have been a very noticeable time difference between the neutrinos and the light at that distance if this were true. (Any astrophysicists about to verify this?)

      SN1987A results were consistent with neutrinos moving at c, although the precise detection time of the optical signal was some hours after the neutrino signal (which was found in subsequent analysis.) John Simpson tried to use an argument about times and average energies to argue for a slightly later than expected arrival time, to support his 17 keV neutrino.

      These results are 60 ns in about 2 ms, or a factor of 0.00003. The LMC (home of SN1987A) is 160,000 light years away, so this would have the neutrino signal arriving several years ahead of the optical signal.

      Ergo, your skepticism is justified. Good call on the comparison measure.

      • by nten (709128) on Thursday September 22, 2011 @10:33PM (#37487408)

        If we detected a neutrino pulse would we have a good enough estimate of direction to look for the light? Or even the notion that we *should* look for a pulse of light several years later in the same region of sky? If we did record both by happenstance, would anyone have correlated the two events? That is weird enough that I'm thinking they wouldn't.

      • These results are 60 ns in about 2 ms, or a factor of 0.00003. The LMC (home of SN1987A) is 160,000 light years away, so this would have the neutrino signal arriving several years ahead of the optical signal.

        Page 3 of the paper in the introduction.

        At much lower energy, in the
        10 MeV range, a stringent limit of |v-c|/c < 2Ã--10-9 was set by the observation of (anti) neutrinos
        emitted by the SN1987A supernova [7].

        Tim.

    • by epine (68316) on Thursday September 22, 2011 @05:02PM (#37484576)

      It only takes a few centimeters of wire to make a 60ns delay

      There are people in the battery industry who will knocking on your door shortly to seize your dielectric material in the interest of national welfare. You need a dielectric constant on the order of 1,000,000 to achieve this (in the context of telegrapher's equations, speed of light varies as sqrt(e_r)). By comparison, relative permittivity of barium titanate ranges up to about 10,000.

      You might want to check your math. It takes only a few keystrokes to google "2cm/c in ns".

      It would be nice someday if Google would give "2cm/c in ps" the same stature. What a world. Even the metric system can't get a fair shake.

      • by forand (530402)
        Try: 2 cm/c in picoseconds I think "ps" is a confused SI abbreviation so they cannot assume they know what you want (although they should be able to from context).
  • by Dr. Spork (142693) on Thursday September 22, 2011 @03:55PM (#37483752)
    Take a look at this useful primer [andersoninstitute.com] about faster than light travel and what it would mean for modern physics. It sure would be interesting. No, amazing!
  • by MetricT (128876) on Thursday September 22, 2011 @04:00PM (#37483822) Homepage

    The numbers in the Reuter's article show the speed of light for neutrinos is 1 part in 40,000 times faster than the speed of light for normal matter.

    I don't think this involves causality violations just yet. All our speed of light experiments to date involve measuring particles involving the electromagnetic force (protons, electrons, photons). Even if confirmed, it could be that there's some measurement error in the EM-derived speed of light, which the neutrino is immune to. In which case, it's not useful for time travel. It simply means our measurement of c was off by a smidge.

    And given the small size of the result, if FTL neutrino communication is proved true, I expect the only real-world application would be financial companies trying to squeeze a few more nanoseconds off NYC-London communications.

  • by adisakp (705706) on Thursday September 22, 2011 @04:04PM (#37483864) Journal
    The detector is 732km away for the emitter and light travels at 299 792 458 m/s. In one billionth of a second, light only travels 29.9 cm. If they are off in the precision of measuring a 732km distance by even as little as 30 cm (~1ft), then their timings will be off by 1 billionth of a second.
  • Verification test? (Score:4, Interesting)

    by The Living Fractal (162153) <banantarr&hotmail,com> on Thursday September 22, 2011 @05:59PM (#37485326) Homepage
    This is ridiculously stupid and simple to ask, but I'll fire away anyway...

    Never stopped me before, why now?

    Did they or do they have some way of sending a 'normal' light signal, like say a powerful radio wave, across the same distance and measuring the travel time? If they see it's 60ns longer than the neutrinos then I think we're getting somewhere, neh?
  • by InterGuru (50986) <jhd.interguru@com> on Friday September 23, 2011 @02:45AM (#37488458) Homepage

    All particles with positive mass go slower than the speed of light.
      Particles with zero mass go at the speed of light.
    Therefore these neutrinos, going faster than c, have negative mass.
    Negative mass, plugged into gravitational formula will give repulsion rather than attraction.
    If the universe is filled with these neutrinos, it would explain the repulsive force we label as dark energy.

    Would someone explain what is wrong with this reasoning?

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