Last year, OPERA measured that neutrinos were making the 454-mile (730-kilometer) underground trip between the two labs more speedily than light, arriving there I thought it might be a good idea to list the possible systematic biases which could lead xkcd's character to win his bet. All of our observations, combined, have enabled us to draw some conclusions about the rest mass of neutrinos and antineutrinos. There's no complicated theoretical analysis that needs to be done to determine whether the speed of light was exceeded. Read again what i wrote, This probably should be a comment. Neutrinos | New Scientist It was the closest observed supernova to Earth in more than three centuries, and the neutrinos that arrived from it came in a burst lasting about ~10 seconds: equivalent to the time that neutrinos are expected to be produced. A careless reading of the paper might make you think that it is contrary to Einstein, but it is not. It would mean that the antineutrino emitted by one nucleus could, hypothetically, be absorbed (as a neutrino) by the other nucleus, and youd be able to get a decay where: There are currently multiple experiments, including the MAJORANA experiment, looking specifically for this neutrinoless double beta decay. Well "possible," yes, but kind of like how tunneling through a brick wall is "possible": while you can't definitively prove it impossible, you'd feel pretty safe saying "this will never happen." Does a password policy with a restriction of repeated characters increase security? In theory, because neutrinos have a non-zero rest mass, it should be possible for them to slow down to non-relativistic speeds. Ignoring the boilerplate media hype about the possibilities of time travel and alternate dimensions - I'm looking for academic sources that might suggest how this could be true, or alternatively, how this discrepancy could be accounted for. This article explains it in a very accessible way: To understand how relativity altered the neutrino experiment, it helps to pretend that we're hanging out on one of those GPS satellites, watching the Earth go by underneath you. We could have done an even better job if we stopped all the traffic, says Dario Autiero, an OPERA team member and a physicist at the Institute of Nuclear Physics of Lyon in France. Therefore, there's a mistake in the computation of the speed of neutrinos, in the calculations on the run lenght, in the interaction time calculations, during the generation and also the detection of those evanescent particles! Actually the impossibility of FTL neutrinos is quite different from the impossibility of tunnelling through a brick wall. But the three types of neutrino all mix together, indicating they must be massive and, furthermore, that neutrinos and antineutrinos may in fact be the same particle as one another: Majorana fermions. It might be possible that the neutrino emitted early are not exactly the same as the one emitted late. They account for the time it takes to process the signal and work backwards from their measurements to determine the time at which the neutrino actually interacted with the detector. a neutrino) would we be able to measure a higher speed. I believe this question needs a couple of years more investigation. Neutrino 'faster than light' scientist resigns - BBC News "Crazy" neutrino find has many physicists skeptical, still backing Einstein. [1]. Are these Articles truthful and Neutrinos do travel faster than light? it is unlikely that the neutrinos go superluminal or SR is not holding true anymore, it is unlikely that the distance is measured incorreclty, it is unlikely that the GPS setup/usage is incorrect. I found that odd given that they do have a downstream muon detector system, but they may be concerned about backgrounds. OPERA experiment If I were conspiratorially minded, I would say they are covering up an uncorrected relativistic effect with a bogus story of a hardware error. Next year, teams working on two other experiments at Gran Sasso experiments - Borexino and Icarus - will begin independent cross-checks of Opera's results. How do we reverse the trend? With due respect to everyone, this reminds of the old EPR remark by Einstein himself - ``everybody says it is wrong for some reason or the other, but curiously, no two people agree on what exactly is wrong with it''. And thats unfortunate, because detecting these low-energy neutrinos the ones that move slow compared to the speed of light would enable us to perform an important test that weve never performed before. (2) OPERA should try to verify that the anomaly has an energy dependence. This means that the shift can only be detected statistically, and it makes the result extremely vulnerable to unanticipated systematic errors, e.g., correlations between the time of emission of the neutrinos and their energy (which strongly affects the efficiency of detection) or the direction of emission. When your particles are travelling on the scale (730534.61 0.20) metres, this is more than enough precision: It's going to take a lot more than grassroots skepticism to think of what could have caused this discrepancy. If so, would it be a real violation of Lorentz invariance or an "almost, but not quite" effect? [2], This experiment doesn't use that sort of 'stopwatch' timing mechanism though. The neutrinos shaved about 60 nanoseconds off that time, according to atomic clocks at either end synchronized by a satellite. After tightening the connection and then measuring the time it takes data to travel the length of the fiber, researchers found that the data arrive 60 nanoseconds earlier than assumed. "That doesn't make sense," they say. The original paper publishing these findings is here: Times of Flight between a Source and a Detector observed from a GPS satelite. (Related: "Proton Smaller Than ThoughtMay Rewrite Laws of Physics."). If neutrinos can move faster than light (FTL) it does not provide a means for FTL propulsion. Nevertheless, theres a tantalizing chance we have to resolve this paradox, despite the difficulty inherent to it. Relativity is really well-tested, and it's really hard to conceive of a way that neutrinos could travel faster than light without it having other consequences that we would have discovered by now. Only one ancient account mentions the existence of Xerxes Canal, long thought to be a tall tale. Well yes, of course it's possible in the same way that it's possible that invisible neutrino fairies are messing around with the neutrinos underground and hence causing havoc with the mental health of physicists around the world. But this is a positive result.". WebA neutrino is an exponentially small particle with no electrical charge. This image shows multiple events, and is part of the suite of experiments paving our way to a greater understanding of neutrinos. They should have simply waited until after they had those data before announcing their results. It will likely take years for their experiment to yield robust results, but any events at all in excess above the expected background would be groundbreaking. The OPERA Experiment and the Value of High-Profile Scientific Leading Light: What Would Faster-Than-Light Neutrinos Mean for Experiments are actively looking for this. Consequences for causality if superluminal neutrinos were explained by extra dimensions, Distance and time measurement in the famous Superluminal Neutrinos Experiment. 2.3k. The origin of this misconception comes from a 2011 result. @Ron, any (general) relativistic effect cannot make the speed superluminal, but it can make your length measurement based on GPS incorrect. "There's no way that a neutrino could have covered the distance we're measuring down here in the time you measured up there without going faster than light!". Given how big this question is, maybe it would be best to delete this answer? The mumblings that begin a few months after the initial report, that a loose cable caused a timing chain error, have been accepted by the experimenters. Why don't we use the 7805 for car phone chargers? Do neutrinos travel faster than the speed of light? Is the wave-particle duality a real duality? In the pic Sat A must be synchronized with C at the same time thru the shortest red path and thru the longest blue path. Concerning your #2: they purport to have dealt with this using the shape-shape fitting between the proton current monitor and the timing of the detection. This doesn't seem right--- could a hardware problem actually do this? The neutrinos are little affected by matter and seem to be covering more "meters" than vacuum meters. Please be respectful of copyright. ", Oscillation Project with Emulsion-tRacking Apparatus, or OPERA, Do Not Sell or Share My Personal Information. The issue we have is twofold: The only neutrino interactions we see are the ones coming from neutrinos moving indistinguishably close to the speed of light. E.g., the delay in the 8.3-km optical fiber has been measured both by two-way timing and using a portable clock, and it's been measured repeatedly over time so that one can rule out changes in optical properties due to aging of the plastic. Today, at the It took more than two decades from when it was first predicted to when it was finally detected, and they came along with a bunch of surprises that make them unique among all the particles that we know of. If the neutrino always moved at the speed of light, it would be impossible to move faster than the neutrino. @Sklivvz The mass of the neutrino is so small that it is irrelevant in the argument, if the refraction is of the order of magnitude of the measurement. Create Your Free Account Its possible to have an unstable atomic nucleus that doesnt just undergo beta decay, but double beta decay: where two neutrons in the nucleus simultaneously both undergo beta decay. "So far no arguments have been put forward that rule out our effect," Dr Ereditato said. is this the result of the experiment you're talking about? There are a myriad of ways the neutrino has shown itself to us, and each one provides us with an independent measurement and constraint on its properties. Those bunches lasted 10 millionths of a second - 160 times longer than the discrepancy the team initially reported in the neutrinos' travel time. If we observe it, it will fundamentally change our perspective on the elusive neutrino. Although we couldnt quite see these neutrinos directly and still cant we can detect the particles they collide or react with, providing evidence of the neutrinos existence and teaching us about its properties and interactions. This will be a tremendous revolutionary finding if it is true, says Chang Kee Jung, a particle physicist at Stony Brook University in New York and a spokesperson for the T2K neutrino experiment in Japan. That confirmation may be much longer in coming, as only a few facilities worldwide have the detectors needed to catch the notoriously flighty neutrinos - which interact with matter so rarely as to have earned the nickname "ghost particles". It will likely take years for their experiment to yield robust results, but any events at all in excess above the expected background would be groundbreaking. The BBC is not responsible for the content of external sites. Heres where the disconnect between theory and experiment lies. What would be the effects on theoretical physics if neutrinos go faster than light? xcolor: How to get the complementary color. @celtschk right, but I'm accounting for the small probability that the known laws of physics are wrong. My answer is only a "would-be" consideration that, if read by the experimenters, could give them some "debug" clues. Given the sheer diversity of possible `goof-up' explanations on this page (all answers combined), I can't help feeling that we are trying to find one plausible way in which this can be MADE to look wrong. The BBC is not responsible for the content of external sites. The history of book bansand their changing targetsin the U.S. Should you get tested for a BRCA gene mutation? When a nucleus experiences a double neutron decay, two electrons and two neutrinos get emitted [+] conventionally. In theory, the neutrinos left over from the Big Bang should have already slowed down to these speeds, where theyll only be moving at a few hundred km/s today: slow enough that they should have fallen into galaxies and galaxy clusters by now, making up approximately ~1% of all the dark matter in the Universe. The solar and atmospheric neutrino experiment results are consistent with one another, but not with the full suite of neutrino data including beamline neutrinos. Thats what Patreon supporter Laird Whitehill wants to know, asking: I know neutrinos travel almost at the speed of light. You must convince yourself that the absolute measurements have the same error bars as the relative measurements, and I did not see that in the arxiv paper. The only explanation is systematic errors in GPS position, GPS time, or bunching statistics. I think what is true is that the group velocity of light as assumed by the experimenters is shown to be smaller than the group velocity of the neutrinos as measured by them. It looks like they took an insane amount of care with their measurement of distance and time. Furthermore, the pulses are quite long (10s), so an error in this analysis could easily be of the good order of magnitude. E.g., it holds both for tachyonic neutrinos without a preferred frame and for models in which neutrinos are not tachyonic and there is a preferred frame. The setup of CERN and OPERA is conceptually very simple, basically just two observers located a known distance apart with synchronized clocks. It depends. Even over cosmic distances, when weve observed neutrinos arriving from galaxies other than the Milky Way, weve detected absolutely no difference between a neutrinos speed and the speed of light. Of course, the current list only contains biases which are unlikely, but less unlikely than a causality violation. Its just odd, says McFarland. Perhaps it is just an indication that the particles in a vacuum are more likely to be electromagnetic-interacting than weak-interacting. But the uncertainties in those measurements were too large to justify calling it a discovery. Neutrino detectors, like the one used in the BOREXINO collaboration here, generally have an enormous [+] tank that serves as the target for the experiment, where a neutrino interaction will produce fast-moving charged particles that can then be detected by the surrounding photomultiplier tubes at the ends. (I actually had something similar happen to me on an experiment: I had an analog signal splitter "upstairs" that sent a signal echo back to my detectors "downstairs", and a runty little echoed pulse came back upstairs after about a microsecond and got processed like another event. Can you plausibly make a 60ns delay by a loose cable? Why does Acts not mention the deaths of Peter and Paul? Before the neutrino was known or detected, it appeared that both energy and momentum were not conserved in beta decays. Remember, from the reference frame of someone on the satellite, we're not moving, but the Earth is. In copper/poly coaxial cable it's slower, about six inches per nanosecond, and in optical fiber it's comparable. There was a very reliable report of finding a monopole in 1980s by Caberera(?). the atomic number of the nucleus changed by 2. but 0 neutrinos or antineutrinos are emitted. This is not a true answer none is knowing the explanation, so far. Ask him to bet against the new results, though, and he says hed be willing to bet his house. Divide distance by time, and the Of course the conclusion would be to investigate if there is one circuit running on one clock pulse less than expected by design / testing. One of the most common skepticism of people who no nothing about the experiment is stuff like: You might worry about[] have they correctly accounted for the time delay of actually reading out the signals? Neutrinos Travel Faster Than Light, According to One Experiment Youd never, no matter how much energy you put into yourself, be able to overtake it. Until theres a revolutionary new technology or experimental technique, this will, however unfortunate it is, continue to be the case. Lets dive on in. But the three types of neutrino all mix together, indicating they must be massive and, furthermore, that neutrinos and antineutrinos may in fact be the same particle as one another: Majorana fermions. Five different teams of physicists have now independently verified that elusive subatomic particles called neutrinos do not travel faster than light. The CMB referential clearly is the only referential to observe the light as isotropic. @Carl: and this is supposed to make one trust their report, independent measurement by the ICARUS collaboration, Times of Flight between a Source and a Detector observed from a GPS satelite, Measurement of the neutrino velocity with the OPERA detector in the CNGS beam, arxiv.org/ftp/arxiv/papers/1109/1109.4897.pdf, Cosmological Principle and Relativity - Part I, Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. @BenCrowell, if this were verified, what energy-dependent effects would we see in Nature? Subscribers, enter your e-mail address for full access to the Science News archives and digital editions. When to average in the lab for indirect measurements? Neutrino oscillation might, for example, then make early neutrino more detectable by the distant detector. A claim that neutrinos traveled faster than the speed of light would be revolutionary if true, but "I would bet against it," physicist says. Is there a generic term for these trajectories? which includes this image: Fermilab might have a better shot. They are not actually using a near detector at all in the usual sense, they are measuring the beam current directly after the pick off magnet, and then correcting for beam TOF down to the target. Once repaired, OPERA also clocked neutrinos as very close to the speed of light, but not surpassing it. Create Your Free Account or Sign In to Read the Full Story. In addition, when you measured the momentum of electron and the post-decay nucleus, it didnt match the initial momentum of the pre-decay nucleus. It's a direct measurement of average velocity. (In fact, five senior members of the collaboration did not put their names on the paper.) I really have a hard time imagining a plausible "goof" explanation at this point. Interpreting non-statistically significant results: Do we have "no evidence" or "insufficient evidence" to reject the null? slow moving neutrinos have very low probabilities of interactions. As the Earth moves we observe a dipole, and in different directions we measure different wavelengths for the same physical object (photon). neutrinos New results, First off, they cannot be zero. It is likely to be several months before they report back. The results of the neutrino experiment shook the world of physics The head of an experiment that appeared to show subatomic particles travelling faster than the speed You would still need to explain why a massive particle (the neutrino) moves faster than a massless particle (the photon). Explore in 3D: The dazzling crown that makes a king. Other proposals could accommodate faster-than-light travel with violating this principle of relativity, says Lee Smolin, a theoretical physicist at the Perimeter Institute for Theoretical Physics in Waterloo, Canada. They then traveled underground to Italys National Gran Sasso Laboratory beneath the Apennines Mountains. If you're going to measure speed (distance / time), you have to get the distance and time both from the same reference frame. The three types of neutrino almost certainly have different masses from one another, where the heaviest a neutrino is allowed to be is about 1/4,000,000th the mass of an electron, the next-lightest particle. The crux of the problem had to do with differing reference frames - the distance traveled according to the satellites which measured the time was different from the distance traveled according to us on earth. All rights reserved. The streams at the input and output are time stamped using the same satellites and any position along each stream has a precise time associated with it. However, slow-moving neutrinos cannot produce a detectable signal in this fashion. What happened to the idea of tachyonic or other superluminal neutrinos? Free. @dmckee: The "partial apology and retraction" is not an apology or a retraction. But [youve implied] their mass dictates that they must travel almost at the speed of light. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Sources: [1] (Associated Press), [2] (Guardian.co.uk), [3] (Original Publication - Cornell University). I suppose an explanation along these lines would mean interesting new particle physics. Today, our mission remains the same: to empower people to evaluate the news and the world around them. I can assure you that the OPERA people are acutely and painfully aware of the long history of highly "significant" bumps just going away. All Things Neutrino was developed byFermi National Accelerator Laboratory, Americas premier laboratory for particle physics and accelerator research. It has been posted to the Arxiv repository and submitted to the Journal of High Energy Physics, but has not yet been reviewed by the scientific community. It would take approximately 26 years for that particle to be detected: the elusive neutrino. It was an unusual configuration and needed unusual termination hardware and I must have answered the question "but couldn't you just" a hundred times.). Can neutrinos really travel faster than the speed of light? What's the cheapest way to buy out a sibling's share of our parents house if I have no cash and want to pay less than the appraised value? But light travels at a constant speed. Neutrinos are tiny subatomic particles, often called 'ghost particles' because they barely interact with anything else. How could a hardware error cause a systematic bias through two different runs of the same size. The author is only clarifying that the GPS community doesn't need to read his paper, because it has no impact GPS best-practices, since the issue of precise time-of-flight is not relevant for most GPS uses. What we can learn from Chernobyl's strays. This paper (Cosmological Principle and Relativity - Part I) analyses the anisotropy of light speed for a moving observer. Neutrinos in the MINOS experiment cover 735 kilometers, about the same distance as CERNs experiment. The neutrino might not actually be travelling as far as they think if space/time is contracted at one or more points along the path where gravity varies. (I'm a theorist, BTW; you do not have to be an experimentalist to acknowledge that. Every neutrino weve ever observed is left-handed (if you point your thumb in its direction of motion, your left hands fingers curl in the direction of its spin, or intrinsic angular momentum), and every anti-neutrino is right-handed. The journey would take a beam of light around 2.4 milliseconds to complete, but after running the Opera experiment for three years and timing the arrival of 15,000 neutrinos, the scientists have calculated that the particles arrived at Gran Sasso 60 billionths of a second earlier, with an error margin of plus or minus 10 billionths of a second. I suspect that the syncronization used in the GPS is in the same as in the above paper and not as Einstein did. The team which found that neutrinos may travel faster than light has carried out an improved version of their experiment - and confirmed the result. Get great science journalism, from the most trusted source, delivered to your doorstep. Faster-Than-Light Neutrinos Aren't - Scientific American Update: Rumors seems to tell that the boring explanation is the good one. Standard Big Bang cosmology corresponds to =1. E-mail us atfeedback@sciencenews.org | Reprints FAQ. It only takes a minute to sign up. But must that be so? Why do the neutrinos (with mass) from a supernova arrive before the light (no mass)? Other I do not agree with the superluminal neutrinos news for very simple reasons. WebAs I have been researching I've come up on many articles claiming that Neutrinos can go faster than the speed of light a miniscule amount but still faster. By Geoff Brumfiel, Nature magazine on September 22, 2011. I will bet all my beans into the idea that they didn't estimate the spacetime curvature inside the earth well and over the beam trajectory, and what they actually discovered is a great way to measure space-time inside the Earth. Nov. 25, 2020 For the first time, the international team was able to directly observe neutrinos from this cycle (CNO Mono-Energetic Neutrinos With Enough Energy to Produce a Muon All rights reserved, "Proton Smaller Than ThoughtMay Rewrite Laws of Physics. Thanks to GPS devices, the distance of this trip, about 730 kilometers, is known to within 20 centimeters a feat of accuracy that required closing a lane of traffic for a week in a tunnel above the detector in Italy. Edit: The "problem" is solved: it was mainly a problem in the timing chain, due to a badly screwed optical fibre. decay at the time. [This paragraph is disproved by the Nov. 17 result.] Workers help build the neutrino-beam facility used at CERN to shoot particles to Italy in a 2005 picture. Extracting arguments from a list of function calls. Weve measured neutrinos and antineutrinos produced by particle accelerator experiments. User without create permission can create a custom object from Managed package using Custom Rest API, If so, would it be a real violation of Lorentz invariance or an ". There have been plenty of papers (well, preprints) have been put forward offering various explanations of the OPERA results, but none of them has been widely accepted yet as far as I know so it's rather premature to say the results have been explained. Send in your Ask Ethan questions to startswithabang at gmail dot com! The explanation for the error provided is cogent, clear, and almost certainly correct. The Neutrino: A Particle Ahead of Its Time I mean, of course, we'll all be very happy if relativity still holds good and there does turn out to be some error, but I hope we are scientific about this whole issue. Are there any canonical examples of the Prime Directive being broken that aren't shown on screen? Video, On board the worlds last surviving turntable ferry, AI pioneer warns of dangers as he quits Google, Shooting suspect was deported four times - US media, Photo of Princess Charlotte shared as she turns 8, Yellen warns US could run out of cash in a month, King Charles to wear golden robes for Coronation, Disney faces countersuit in feud with Florida, Explosion derails train in Russian border region, US rock band Aerosmith announce farewell tour. Your support enables us to keep our content free and accessible to the next generation of scientists and engineers. Neutrinos are tiny, electrically neutral particles produced in nuclear reactions. Last September, an experiment called OPERA turned up evidence that neutrinos travel faster than the speed of light (see ' Particles break light speed limit '). I was quite surprised to read this all over the news today: Elusive, nearly massive subatomic particles called neutrinos appear to travel just faster than light, a team of physicists in Europe reports. So if this is true, it would rock the foundations of physics," said Stephen Parke, head of the theoretical physics department at the U.S. government-run Fermilab near Chicago, Illinois. A new discovery raises a mystery. Nothing can accelerate to any faster speed. But archaeology is confirming that Persia's engineering triumph was real. They then compared this plot against a plot of the arrival times of the 15,223 detected neutrinos. This comparison indicated neutrinos had arrived at the detector 57.8 nanoseconds faster than if they had been traveling at the speed of light in vacuum. No one has forgotten this. If neutrinos obey this see-saw mechanism and are Majorana particles, neutrinoless double beta decay should be possible. ', referring to the nuclear power plant in Ignalina, mean? The GERDA experiment, a decade ago, placed the strongest constraints on neutrinoless double beta [+] decay at the time. When a photon is released in space it starts its journey at c speed independently of the source and of the receiver. VideoOn board the worlds last surviving turntable ferry, I didnt think make-up was made for black girls, Why there is serious money in kitchen fumes. As the neutrino experiment goes by, we start timing one of the neutrinos as it exits the source in Switzerland. Usually, you just lose some pulses travelling down the cable. When the Opera team ran the improved experiment 20 times, they found almost exactly the same result. Inevitably, if this turned out to be the case, the real upper limit is slightly higher again, since neutrinos are massive and thus move below the maximum speed. Copyright 1996-2015 National Geographic Society, Copyright 2015-2023 National Geographic Partners, LLC. It's still gossip, so take this with abundance of caution, but here's what he had to say: According to sources familiar with the experiment, the 60 nanoseconds discrepancy appears to come from a bad connection between a fiber optic cable that connects to the GPS receiver used to correct the timing of the neutrinos flight and an electronic card in a computer.
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