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Featured I What false hints of new physics were most notable?

  1. Apr 15, 2018 #1

    ohwilleke

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    Sometimes experimental or observational evidence from credible physicists points to new physics and then turns out to be wrong due to statistical flukes, experimental error or a theoretical analysis mistake.

    What cases of this happening do you find most notable, what showed that the hints were unfounded, and why do you find them most notable? I'll start with four, to which you can add your own (or which you can discuss in their own right).

    Also, what lessons should be learn from these experiences as new hints of BSM physics come up over time?

    Ultimately, I find that these false starts strengthen my confidence in the scientific process, because they were doggedly analyzed and ultimately debunked, suggesting that the scientific community is appropriately skeptical even in the face of announcements from authoritative sources.

    (For clarity, this thread is not about cases where experiments actually established what constituted new physics at the time or currently unresolved anomalies. It is only about new physics "fails" that at first looked like proof of new physics.)

    1. Opera's announcement that it had observed superluminal neutrinos.

    In 2011, the Opera collaboration had detectors at a collider and then another detect hundreds of kilometers away. By coordinating observations from those detectors and using precision clocks, they reported that neutrinos seemed to be moving slightly faster than the speed of light, which is prohibited by Special Relativity. The problem in their instrumentation was revealed nine months later.

    This was notable because it was a widely reported result of a major big physics collaboration and went to the very fundamental laws of general and special relativity illustrating how the physics community might respond if a real breakthrough did happen. In the end, it turns out to be due to a wiring problem in the measurement equipment.

    2. The purported discovery of cold fusion.

    In 1989, Martin Fleischmann (then one of the world's leading electrochemists) and Stanley Pons reported that their electrolysis-like setup was generating modest amounts of net energy, which they attributed to a low temperature fusion process.

    This was notable because is was proposed by respected scientists despite a lack of any well articulated theoretical basis why it should happen, was widely publicized, and would have had profound economic effects if true. The result was not replicated (something that should have been easy to do in their table top setup) and when studied more carefully did not show signs of fusion byproducts. Within a few months the discovery was discredited.

    In some ways, this is the most puzzling of the four incidents that I list here, because the scientists involved knew that they were making extraordinary claims, but did not exercise the extreme care that they should have to make sure that their evidence was similarly extraordinary before announcing it.

    It may be that the commercial potential of this claimed discovery put pressure on Fleishmann and Pons to announce their results early in the face of the likelihood that someone would leak this inexpensive to carry out process, potentially depriving them of an inventor's profits from the discovery. The other three examples that I cite had no real commercial application in the short to medium term, even if they were true, and were difficult or impossible for more than a handful of research collaborations to replicate or stumble upon in the meantime.

    3. The Pioneer anomaly.

    A lot of the research discovering and than explaining this anomaly came from high prestige and authority NASA scientists. As the linked Wikipedia article summarizes:

    Thus, in this case the measurements showing the anomaly were accurate but the theoretical analysis used to determine the predicted value missed one very subtle point.

    While this was a less high profile issue in the popular press than Opera's superluminal neutrinos or Cold Fusion, it too went to very fundamental points of the law of General Relativity in a very clean solar system test never before conducted where there was anomaly that was correctly measured and statistically significant.

    Also, while the other two were ruled out in a matter of months, this anomaly wasn't conclusively explained for 32 years, and it took four years of serious investigation before the result that ultimately came to be accepted was proposed.

    4. The 750GeV diphoton excess.

    In 2015, the LHC saw events which pointed to a new particle with a mass of 750 GeV in the very clean diphoton channel in which the Higgs boson was discovered, and many new physics theories, such as "two Higgs doublet" theories predicted a Higgs boson-like particle for which that mass would have been plausible. It turned out that this was a statistical fluke and when more data was collected in 2016, the combined data actually disfavored the existence of this resonance.

    This is very much an "inside baseball" incident that attracted a massive rush of papers from physicists but received much less attention in the general public. But, it is particularly notable because the high prestige physics collaborations in question in this case made no experimental or theoretical mistakes, they just happened to be suckered by a fluke of random chance.

    Also, it is hard to fault the physicists in the "gold rush" of papers written to explain this phenomena, because the practical reality in the scientific community is that to receive credit for making important discoveries, you have to articulate theories describing anomalies in published papers long before they reach the generally accepted five sigma discovery threshold. So, you have little choice but to take the risk that an anomaly will turn out to be a fluke if you want to have any hope of ever being considered an important figure in discovering BSM phenomena.
     
    Last edited: Apr 15, 2018
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  4. Apr 15, 2018 #3

    Haelfix

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    I would say the discovery of the pentaquark by LEPs was one of the more important one for insiders. Simply b/c it was plausible theoretically and indeed had been predicted at that mass range earlier. It also had a very large local significance (4.6 sigma) and fractioned a good amount of the community. It was thus interesting both in the sociology as well as a cautionary tale for experimentalists.
     
  5. Apr 15, 2018 #4

    phyzguy

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    This is a nice list. I can think of a few others:

    Supraluminal motions in quasars: In the 1970's several quasars were observed with transverse motions that were much faster than the speed of light. Many people claimed that these were proof that these objects couldn't be at the cosmological distances that were claimed. It was eventually understood that if the motion is directed near the line of sight, relativistic time dilation can lead to apparent transverse motions much greater than the speed of light.

    N-Rays: Further in the past, the N-Ray saga is a great cautionary tale about the dangers of relying on subjective perception as opposed to objective measurements.
     
  6. Apr 16, 2018 at 12:33 AM #5

    mfb

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    LEP was not the only accelerator where experiments thought to see pentaquarks, HERA had three as well for example (experiments, not pentaquarks). Wikipedia has some more.

    Not a false hint of new physics, but a false hint of actual physics: Searching the top quark was done in many different decay modes ("channels") together, with just a few top events expected per channel. At this time Monte Carlo simulations were not very reliable, and scientists sometimes used the observed events to define their selections. From a modern perspective it is obvious what happened: Every group made a selection that kept their favorite events in and obvious background events out. Even for the same type of object the experiments had completely different selection criteria. At some point the scientists conceded that this was not a very scientific approach, and made the selection criteria uniform - after a lot of fighting because some groups lost their events and the quoted significance went down. It was then discovered with a larger dataset.
    Today it is standard practice to develop the selection independent of the physics you are interested in.

    Another false hint of SM physics: Towards the end of LEP the machine energy was increased more and more in the hope to find the Higgs boson. Some LEP scientists claimed to see a hint of it right at the edge of the achieved energy, corresponding to a Higgs mass of 115 GeV. It was a very controversial claim, and not enough to keep LEP running any longer. Today we know there was no actual signal.
     
  7. Apr 16, 2018 at 6:58 AM #6
    Cold Fusion was more or less the prototypical example in my lfetime.

    Not that it was really important, but a few years back colleagues and I had three data sets that seemed to show that the force of air drag was not proportional to air density in a case where proportionality should have been near perfect within our experimental uncertainty which was about 1%. Having learned the lesson of cold fusion, rather than rush to publish, we endeavored to reduce the error and perform the experiment again. When we repeated the experiment, we found agreement between the force of drag and air density to within our experimental error.

    Science is a tentative business, and the science of error bars is even more tentative. There are often assumptions made when estimating uncertainties that are reasonable and probable given the available information, but often there is simply insufficient information available to rigorously prove these assumptions. I tend to view error bars as the best available estimate of the uncertainties given the available information at the time rather than anything written in stone.

    I have often wondered, "What is the uncertainty on those error bars?" This is a difficult question for which there is no rigorous and generally applicable answer. My ad hoc approach is to double the error bars in my mind and consider whether the import or impact of a given experimental result changes. Justification? 30 years of experience in a broad ranges of disciplines and experiments showing that while errors were occasionally larger than the best available estimates of the uncertainty, it was rare for the uncertainty to be off by more than a factor of two if the estimation process was reasonable.
     
  8. Apr 16, 2018 at 11:42 AM #7

    ohwilleke

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    Another one was BICEP2 which claimed to have seen primordial gravitational waves in the cosmic background radiation, but was actually a victim of sloppy data borrowing from someone else's conference paper. As the link explains, there is now a book out about the incident.
     
  9. Apr 16, 2018 at 11:44 AM #8

    ohwilleke

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    Often this makes good sense. On the other hand, at the LHC, the error bars for electroweak physics are consistently overestimated with result after result producing measurements that are way too good for the claimed error bars.
     
  10. Apr 16, 2018 at 12:15 PM #9

    Vanadium 50

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    I was there for the top quark discovery and this is not how I remember it.
     
  11. Apr 16, 2018 at 2:33 PM #10

    mfb

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    This is how Boaz Klima (DØ at that time) describes it. I was not there, I can only write what I hear from others.
     
  12. Apr 16, 2018 at 4:45 PM #11

    Ygggdrasil

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    A great historical example is the hunt for the planet Vulcan (https://news.nationalgeographic.com...ry-astronomy-theory-of-relativity-ngbooktalk/)

    Essentially, astronomer's saw that Mercury's orbit did not match the predictions of Newtonian mechanics. Scientists therefore hypothesized that another undiscovered planet must be influencing the orbit of Mercury. We now know that mercury's orbit does not match the predictions of Newtonian physics because of special general relativity. Special General relativity accurately explains Mercury's orbit, "proving" that Vulcan does not exist.

    This is one of the cases where scientists made an observation that did not fit theoretical expectations and it turns out that the theory was wrong (not the observation). While scientists were successfully able to predict the existence of Neptune solely by relying on calculations, the example of Vulcan shows that discoveries made purely by computation always need to be confirmed by direct observation/experiment because you never know if the underlying math is wrong.
     
    Last edited: Apr 16, 2018 at 5:54 PM
  13. Apr 16, 2018 at 5:13 PM #12

    anorlunda

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  14. Apr 16, 2018 at 5:45 PM #13

    mfb

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    General relativity. Special relativity does not include gravity.
     
  15. Apr 17, 2018 at 2:08 PM #14
    I remember in the 80´s my father, who worked in NMR and MRI at the time, got a fax of a pre-print paper regarding memory effects on water. Thermal fax paper was expensive then, I remember him being upset at the waste of money...
    Found it on https://en.wikipedia.org/wiki/Water_memory. Quote: "Benveniste was a French immunologist who sought to demonstrate the plausibility of homeopathic remedies "independently of homeopathic interests" in a major scientific journal.[3]"
     
  16. Apr 18, 2018 at 4:41 PM #15
    The first item on your list does not belong on the list! The reason is because any physics undergraduate with paper and pencil ca prove in five minutes than faster than light travel or communication is impossible.

    Read the following websites.

    http://www.askamathematician.com/2012/07/q-how-does-instantaneous-communication-violate-causality/

    https://physics.stackexchange.com/q...ith-speed-greater-than-light-breaks-causality

    There are some things which in some sense could be said to involve something going faster than light, such as the EPR paradox, so-called "spooky action at a distance", or the expansion of the Universe, but none of these things would allow you to send a message faster than light.

    In special relativity, a particle moving FTL in one frame of reference will be travelling back in time in another. FTL travel or communication should therefore also give the possibility of travelling back in time or sending messages into the past. If such time travel is possible, you would be able to go back in time and change the course of history by killing your own grandfather.

    Let's say neutrinos went faster than light. You could, by turning the machine on and off, use Morse code to send a message backwards in time, and the message could read "Do not send the message", so if you don't send the message, then you do send it, and if you do send it, then you don't send it. Since that's a paradox. that means neutrinos could not go faster than light.

    There is a difference between a statement being factually wrong, and a statement being meaningless. The statement that the Great Pyramid of Giza has a volume of three cubic inches is factually wrong. The statement that the Great Pyramid of Giza has a volume of -45 cubic feet is meaningless because the volume of an object can not be a negative number. To claim that the velocity of a neutrino could be faster than light is a similar meaningless statement.

    Let's say that a boy in 8th grade was given a math homework problem where he was supposed to calculate the volume of the Great Pyramid of Giza, and he arrived at an answer of -45 cubic feet. Well, he knows he must have made a mistake since the volume of an object can not be a negative number. He checks his work over and over again, and can not find his mistake. Then he shows his work to other people, and asks them to help find where he made his mistake.

    Let's say that this story was then picked up by the Associated Press, and hundreds of journalists wrote articles announcing that the volume of the Great Pyramid of Giza is actually -45 cubic feet, apparently unaware that the volume of an object can not be a negative number.

    This is the same as what actually happened. One newspaper printed the ludicrous headline "Roll Over Einstein". The problem is that the average non-scientist does not realize that traveling faster than light in one frame is traveling backwards in time in another frame, and instead they imagine it as like you're driving down the road, and you pass a sign that says "65 mph", but despite that, you COULD put your foot on the accelerator and go faster, and hope that you are not pulled over by the cops, so they imagine that maybe sneaky neutrinos are breaking the rules. That is wrong!

    It is easy to prove than faster than light communication is impossible because it would violate causality. You should not have included that in your list!
     
  17. Apr 18, 2018 at 4:56 PM #16
    Hi David,
    That was a thorough discussion on the existing theory. Thanks.
    But if one ignores potential new observations that contradict existing theory, then we would be missing an important step in the scientific process...
    Anyway, the original point was: "Sometimes experimental or observational evidence from credible physicists points to new physics..."
    Naturally experimenters should try to find explanations for what they observe that doesn´t fit the theory, but hey, if they can´t figure it out, publish it...
    Cheers and good ´sciencing´ everyone.
    RP

     
  18. Apr 18, 2018 at 5:32 PM #17
    I agree that we should not ignore new observations that contradict existing theory. However, there is a difference between new observations that contradict existing theory and a claim that leads to a paradoxical conclusion.
     
  19. Apr 18, 2018 at 6:46 PM #18

    ohwilleke

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    There are a number of paradoxes out there already when viewed in the context of the laws of physics believed to apply at the time of their discovery. For example, the Bell Inequalities of QM, or special relativity's conclusions viewed via classical Newtonian mechanics.

    There were hundreds of superluminal neutrino papers out there trying to resolve the apparently paradox. People are creative. The resolutions of the apparent paradoxes could have worked if the data had held up. You can be skeptical of new physics experimental results, but the fact that they create a paradox within the scope of existing physics is no reason to ignore them.

    For example, if our determinations of the speed of light in a vacuum were actually measuring the speed of light in a non-vacuum medium (call it aether for old times sake) that neutrinos did not interact with, that we had previously not be known to exist, that would resolve the paradox. It would do so because Lorentz invariance relates to the maximum speed of light in a vacuum, not the lower maximum speed of light in some medium. For example, the fact that it is possible to observe something traveling at faster than the speed of light in water causes no difficulties conceptually.

    As long as there is some speed "c" that is maximal and used to calculate Lorentz transformations, you can still avoid causality problems and paradoxes. it doesn't terribly matter if it is photons or something else that travels at that highest possible speed, or for that matter if nothing reaches the asymptotic peak speed because all fundamental particles believed to be massless actually have some negligible mass. Similarly, if photons, contrary to widespread belief, actually had negligible mass, there would be no problem.

    Similarly, a parts per million scale difference in the absolute magnitude of "c" is really not such a big deal conceptually. Notable yes, but not Earth shaking.

    Obviously, none of that happened. But, experiments that contradict existing physical laws sometimes are occasions for progress, and abandonment of an old paradigm.
     
  20. Apr 19, 2018 at 2:55 AM #19

    Demystifier

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    Yes, the undergraduate can prove it, by assuming that the theory of relativity (in its standard form) is valid. Every proof in theoretical physics or pure mathematics depends on some assumptions (axioms) that one didn't prove. In this case, the assumption is theory of relativity. In principle, it is logically possible that theory of relativity is violated in some cases, perhaps with neutrinos. An experimentalist has a right to question any standard assumption of theoretical physics, including the assumption of the theory of relativity. Therefore, the first item absolutely deserves to be on the list.
     
  21. Apr 19, 2018 at 4:09 AM #20
    I was wondering if there has been any more study on the 240 GeV Higgs like fluctuation. Or does the LHC need to collect more data. It would be interesting to see a list of scientific discoveries that were great, but originally were trashed.
     
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