Recently, information appeared in the media about observations of the superluminal speed of neutrino movement. As noted, the average neutrino speed exceeded the speed of light by 0.00248%, which is 7435 m / s. For some, this undermines the foundations of the theory of relativity. We offer the following explanation for the observed facts, which does not contradict the theory of relativity.
In theoretical physics, instead of the concept of "speed of light in vacuum", the concept of "fundamental speed" is often used. The fundamental speed is the speed that is used in the Lorentz transformations, is included in the famous Einstein's formula, it is an invariant of any space-time transformations of reference frames. It is the fundamental speed that is meant when they say that it is impossible to exceed it. The speed of light is the speed of propagation of light as a physical phenomenon. So the speed of light in a vacuum and the fundamental speed, generally speaking, are different concepts. And quantitatively they can also differ, albeit very slightly.
The confusion of these concepts until now has not led to misunderstandings due to the fact that all experiments to test (and confirm) the theory of relativity gave for the fundamental speed exactly the value that the speed of light in vacuum had (within the limits of observation errors). Now, after the appearance of new data on the superluminal speed of neutrino motion, the following hypothesis is emerging.
There is no excess of the fundamental speed. But there is an excess over the speed of light. Neutrinos always move at a fundamental speed. But light moves at a speed slightly less than the fundamental one, which leads to the conclusion about the superluminal speed of the neutrino.
Adding the speed of light in a vacuum with the excess of the neutrino speed, we get the value of 299799893 m / s for the fundamental speed. All the formulas of the theory of relativity remain in force, but the fundamental conclusion from all of the above is that photons can be stopped, that they have a nonzero rest mass. Unfortunately, it is not clear from the published data what color photons were used to measure their speed. Therefore, we assume that it is yellow, with an energy of 2.15 eV. Then, comparing the energy of yellow photons with the formula for the energy of a body moving with speed v
where h is Planck's constant, ν is the photon's frequency, m 0 is its rest mass, we obtain for the latter its value 2.68 10 -38 kg, which is 2.9 10 -8 electron rest mass.
Note now that the photons different color have different energies. How does this relate to their speed? There are two options to consider here. The first is that all photons move with the same speed, equal to 299792458 m / s, photons of different colors differ from each other by different rest mass. That is, there are a lot of varieties of photons. Second - photons of all colors have the same rest mass, differ from each other in speed. If this is so, then the blue photons, with an energy of 2.7 eV, move at speeds lower than the fundamental, by 0.00155%. Thus, the difference between the speeds of the blue and yellow photons is 0.00093% of the fundamental speed, or, in absolute units - 2.8 10 3 m / s. This means that the blue photons in the process of movement should be slightly ahead of the yellow ones. And this, in turn, means that there is the following possibility of testing the above hypothesis.
Let in our Galaxy at a distance of 3 pc. some event occurred from the Earth, accompanied by the emission of photons of all colors. Then, based on the above numbers, we find that the blue photons will arrive on Earth 48 minutes earlier than the yellow ones. This is quite observable.
Further, the verification could be carried out by observations of the Cepheids. It is known that Cepheids are objects of variable brightness. It is natural to assume that the maximum brightness of the Cepheid in the yellow part of the spectrum should coincide with the maximum of its brightness in the blue, if observations are carried out in close proximity. When observing from the Earth, there should be a time shift between the brightness maxima in the yellow and blue parts of the spectrum. This effect should be directly proportional to the distance between the Earth and the Cepheid.
Pinsk, Belarus
It is well known that the tachyon hypothesis does not contradict the basic principles of SRT. You should immediately pay attention to the fact that the well-known postulate of the theory says about the constancy of the speed of light, and not its maximum.
When Einstein wrote down his postulates for the special theory of relativity, he did not add to them the postulate about the impossibility of superluminal motion. Some people mistakenly believe that the impossibility of superluminal motion is a consequence of existing postulates.
you're wrong
Photon - EMW, EMW has NO mass and at rest it does not exist, therefore, personally for a photon, one cannot associate its Energy with the concept of its Mass. The concept of "Energy" is universal, and the concept of Mass is narrow, it refers only to objects that have it and is not applicable to a photon. And the speed of EME in a vacuum, as it is written here, is a limiting process, the speed of propagation of which does not depend on the wavelength. The speed decreases when passing through the medium due to the specific interactions of the EMW = photon with the in-vom. The wavelength in the space also decreases proportionally, without actually increasing the Energy (there are no losses), in contrast to the different-frequency EMW = photons in a vacuum, the equivalent energy of which is different.
The OPERA scientific group repeated the experiment to measure the speed of neutrinos and confirmed the previously obtained sensational data on exceeding the speed of light; according to the new results, neutrinos flew a distance of 730 kilometers 57 nanoseconds faster than light, project participant Natalya Polukhina, head of the laboratory, told RIA Novosti elementary particles Institute of Physics named after Lebedev RAS (FIAN).
At the end of September 2011, physicists of the OPERA collaboration, participants in the experiment of the same name to study neutrino oscillations, announced that the speed of these particles measured by them exceeded the speed of light. According to these scientists, neutrinos flew 730 kilometers from the SPS accelerator at CERN in Switzerland to the underground detector in the Gran Sasso tunnel (Italy), on average, 60 nanoseconds faster than the calculations suggested.
This triggered a flood of press reports about the "refutation" of Einstein's theory of relativity. The authors of the sensation themselves are inclined to believe that we are talking about some distortions that have not yet been noticed. Before the official publication of the results in a scientific journal, scientists decided to repeat the experiment and remove some of the factors that could cause the observed deviation. Ultimately, however, the superluminal result was confirmed.
"The test results are known, the collaboration and independent experts checked everything very carefully, an additional neutrino beam from CERN was specially organized, the result remained practically the same - not 60, but 57 nanoseconds," Polukhina said.
According to her, the level of reliability of the result remained at the same level - six standard deviations (to talk about a discovery, physicists only need to get five standard deviations).
"The collaboration did not find an error in the measurements, the article will be published, there will be a wider discussion. It is not known what is wrong, because everything imaginable and inconceivable has been checked. Let's see what the public will say, because this result turns everything too much," she added. ...
She said that participants in the MINOS neutrino experiment at the American Fermi Laboratory will also be involved in verifying the OPERA data.
“They said that they would repeat this result within three months, but I doubt that this is possible, because the technique is serious, it needs to be installed, debugged. It took OPERA two years to debug the system. On the other hand, OPERA is ready to hand over my equipment, and I’m ready to help, ”Polukhina said.
In the OPERA experiment, protons accelerated at CERN on the SPS proton supersynchrotron to energy and 400 gigaelectronvolts hit a graphite target, generating mesons and kaons. These particles fly through a kilometer-long vacuum tunnel in the process of decay, generating neutrinos, which, in turn, are sent on a 730-kilometer journey through the earth's thickness to the laboratory in the Gran Sasso tunnel (Italy), where they are met by the detector op.
To determine the speed of a neutrino, it is necessary to measure the path and the time it takes a particle to pass this path. The distance between CERN and the OPERA detector (732 kilometers) is measured with an accuracy of 20 centimeters, and the time of arrival of neutrinos is measured with an accuracy of 10 nanoseconds. Using such averaged data for 16,000 neutrinos, a result was obtained that the speed of light was exceeded by 60 nanoseconds - a result that is now corrected to 57 nanoseconds.
In the first experiment, the scientists used 10 microsecond proton pulses containing five nanosecond beam dumps. However, in a repeated experiment, they used shorter pulses of 1-2 nanoseconds duration with pauses of 500 nanoseconds in order to obtain a more "clear" front of the neutrino wave and eliminate possible errors.
"An internal check of the collaboration has not yet found anything, the result remains and will be published," Polukhina concluded.
Not much time has passed ... 27-12-2011 and New theoretical arguments are found against the possibility of superluminal neutrino motion:
Having performed relatively simple calculations based on the laws of conservation of energy and momentum for decays, the authors showed that under the conditions of the OPERA experiment - when neutrinos and pions with average energies of ~ 17.5 and ~ 60 GeV are used - the parameter α should not rise above 4.10 -6. To allow the measurement of α = 2.5.10 -5, the lifetime of pions must be increased by about six times. The possibility of such a serious change in the parameters of particles is, of course, excluded.
Even stricter limits on α, according to physicists, are set by the IceCube experiment, which detects high-energy neutrinos and muons of astrophysical origin. The IceCube detector is a set of recording modules equipped with photomultiplier tubes and strung on a "string". These assemblies are installed at a depth of 1,450 to 2,450 m in the ice, and charged particles produced by neutrino interactions and moving at a speed exceeding the phase velocity of light propagation in ice generate Cherenkov radiation, which is monitored by photomultipliers.
Based on the first observation results, which were recently published by the IceCube collaboration, the authors found that α should not exceed 10 -12. "As you can see, it is extremely difficult to obtain superluminal neutrinos without violating the laws known to modern physics," concludes the head of the study, Ramanath Cowsik. - At the same time, one cannot make any claims to the OPERA collaboration: they carefully checked their data and made them public only when they tried all the methods of finding errors. Obviously, some mistake still went unnoticed, and now we - the entire physical community - must help detect it. "
The full version of the report, prepared by Mr. Kousik and colleagues, is published in Physical Review Letters; a preprint of the article can be downloaded from the arXiv website.
Prepared based on materials University of Washington at St. Louis .
| News Announcements - what is this? |
| Glory and first death Futuristic Science Fiction:. 27-07-2019 |
| Why artists become presidents About how seasoned journalists, bloggers and artists use their skills to lie in favor of their performances and actively promote this lies with the methods of sophisticated, long-rehearsed rhetoric. : . 26-06-2019 |
| Features of understanding circuitry systems What are the main reasons for the current misunderstanding of the functions of the adaptive levels of the evolutionary development of the brain: |
A neutrino is an elementary particle that is very similar to an electron, but has no electrical charge. It has a very low mass, which may even be zero. The speed of the neutrino also depends on the mass. The difference in time of arrival of the particle and the light is 0.0006% (± 0.0012%). In 2011, during the OPERA experiment, it was found that the speed of neutrinos exceeds the speed of light, but independent experience has not confirmed this.
It is one of the most abundant particles in the universe. Since it interacts very little with matter, it is incredibly difficult to detect. Electrons and neutrinos do not participate in strong nuclear interactions, but they also participate equally in weak ones. Particles with these properties are called leptons. In addition to the electron (and its antiparticle, the positron), charged leptons include the muon (200 electron masses), tau (3500 electron masses), and their antiparticles. They are called that: electron, muon and tau neutrinos. Each of them has an anti-material component called antineutrino.
Muon and tau, like an electron, have accompanying particles. These are muon and tau neutrinos. The three types of particles differ from each other. For example, when muon neutrinos interact with a target, they always produce muons, never tau or electrons. When particles interact, although electrons and electron-neutrinos can be created and destroyed, their sum remains unchanged. This fact leads to the division of leptons into three types, each of which has a charged lepton and an accompanying neutrino.
Very large and extremely sensitive detectors are needed to detect this particle. Typically, low-energy neutrinos will travel for many light years before interacting with matter. Consequently, all ground-based experiments with them rely on measuring a small fraction of them, interacting with registrars of reasonable sizes. For example, at the Sudbury Neutrino Observatory, which contains 1000 tons of heavy water, about 1012 solar neutrinos pass through the detector per second. And only 30 are found per day.
Wolfgang Pauli first postulated the existence of a particle in 1930. A problem arose at the time because it seemed that energy and angular momentum were not conserved in beta decay. But Pauli noted that if a non-interacting neutral neutrino particle is emitted, then the law of conservation of energy will be observed. The Italian physicist Enrico Fermi in 1934 developed the theory of beta decay and gave the particle its name.
Despite all the predictions, for 20 years neutrinos could not be detected experimentally because of it with matter. Since the particles are not electrically charged, they are not affected by electromagnetic forces, and, therefore, they do not cause ionization of matter. In addition, they only react with matter through weak interactions of little force. Therefore, they are the most penetrating ones, capable of passing through a huge number of atoms without causing any reaction. Only 1 in 10 billion of these particles, traveling through matter at a distance equal to the diameter of the Earth, reacts with a proton or neutron.
Finally, in 1956, a group of American physicists led by Frederick Reines reported that in their experiments, antineutrinos emitted from a nuclear reactor interacted with protons to form neutrons and positrons. The unique (and rare) energy signatures of these latest byproducts have become evidence of the particle's existence.
The discovery of charged muons leptons became the starting point for the subsequent identification of the second type of neutrino - muon. Their identification was carried out in 1962 based on the results of an experiment in a particle accelerator. High-energy muonic neutrinos were produced by the decay of pi-mesons and sent to the detector in such a way that it was possible to study their reactions with matter. Although they are unreactive, like other types of these particles, it has been found that on the rare occasions when they reacted with protons or neutrons, muon-neutrinos form muons, but never electrons. In 1998, American physicists Leon Lederman, Melvin Schwartz, and Jack Steinberger obtained Nobel Prize in physics for the identification of muon-neutrinos.
In the mid-1970s, neutrino physics was supplemented by another type of charged lepton - tau. Tau neutrinos and tau antineutrinos were found to be associated with this third charged lepton. In 2000, physicists at the National Accelerator Laboratory. Enrico Fermi reported the first experimental evidence for the existence of this type of particle.
All types of neutrinos have a mass that is much less than that of their charged counterparts. For example, experiments show that the electron-neutrino mass should be less than 0.002% of the electron mass and that the sum of the masses of the three varieties should be less than 0.48 eV. For years, the particle seemed to have zero mass, although there was no conclusive theoretical evidence as to why this should be the case. Then, in 2002, the first direct evidence was obtained at the Sudbury Neutrino Observatory that electron-neutrinos emitted by nuclear reactions in the core of the Sun change their type as they pass through it. Such "oscillations" of neutrinos are possible if one or several types of particles have some small mass. Their studies of the interaction of cosmic rays in the Earth's atmosphere also indicate the presence of mass, but further experiments are required to determine it more accurately.
Natural sources of neutrinos are the radioactive decay of elements in the interior of the Earth, during which a large flux of low-energy electrons, antineutrinos, is emitted. Supernovae are also predominantly neutrino phenomena, since only these particles can penetrate the superdense material formed in the collapsing star; only a small part of the energy is converted into light. Calculations show that about 2% of the Sun's energy is the energy of neutrinos formed in thermonuclear fusion reactions. It is likely that most of The dark matter of the universe is made up of neutrinos formed during the Big Bang.
The fields related to neutrinos and astrophysics are diverse and rapidly evolving. Current issues attracting a large amount of experimental and theoretical effort are as follows:
One of the long-standing problems of particular interest is the so-called solar neutrino problem. This name refers to the fact that several ground-based experiments conducted over the past 30 years have consistently observed fewer particles than are needed to produce the energy emitted by the sun. One of its possible solutions is oscillation, that is, the transformation of electron neutrinos into muonic or tau during their journey to Earth. Since it is much more difficult to measure low-energy muon or tau neutrinos, this kind of transformation could explain why we do not observe the correct number of particles on Earth.
The 2015 Nobel Prize in Physics was awarded to Takaaki Kajita and Arthur MacDonald for their discovery of the neutrino mass. This was the fourth such award associated with experimental measurements of these particles. Someone may be interested in the question of why we should be so worried about something that interacts with difficulty with ordinary matter.
The very fact that we can detect these ephemeral particles is a testament to human ingenuity. Since the rules of quantum mechanics are probabilistic, we know that even though almost all neutrinos pass through the Earth, some of them will interact with it. Detector is enough big size able to register it.
The first such device was built in the sixties deep in a mine in South Dakota. The shaft was filled with 400,000 liters of cleaning fluid. On average, one neutrino particle interacts with a chlorine atom every day, converting it into argon. Incredibly, Raymond Davis, who was in charge of the detector, came up with a way to detect these few argon atoms, and four decades later, in 2002, he was awarded the Nobel Prize for this amazing technical feat.
Because neutrinos interact so weakly, they can travel great distances. They give us the opportunity to look into places that we would otherwise never see. Davis's neutrinos were formed from nuclear reactions that took place in the very center of the sun, and were able to leave this incredibly dense and hot place only because they barely interact with other matter. It is even possible to detect neutrinos flying from the center of an exploding star more than a hundred thousand light-years from Earth.
In addition, these particles make it possible to observe the Universe at its very small scales, much smaller than those that the Large Hadron Collider in Geneva can look into, which discovered it is for this reason that the Nobel Committee decided to award the Nobel Prize for the discovery of another type of neutrino.
When Ray Davis observed solar neutrinos, he found only a third of the expected number. Most physicists believed that the reason for this was poor knowledge of the astrophysics of the Sun: perhaps the models of the interior of the star overestimated the number of neutrinos produced in it. However, over the years, even after solar models improved, the deficit persisted. Physicists drew attention to another possibility: the problem could be related to our ideas about these particles. In accordance with the then prevailing theory, they did not possess mass. But some physicists argued that in fact the particles had an infinitesimal mass, and this mass was the reason for their lack.
According to the theory of neutrino oscillations, there are three of them in nature. different types... If a particle has mass, then as it moves, it can change from one type to another. Three types - electronic, muon and tau - when interacting with matter can be transformed into the corresponding charged particle (electron, muon or tau lepton). "Oscillation" is due to quantum mechanics. The type of neutrino is not constant. It changes over time. A neutrino, which began its existence as an electronic one, can turn into a muonic one, and then back again. Thus, a particle formed in the core of the Sun, on its way to the Earth, can periodically turn into a muon-neutrino and vice versa. Since the Davis detector could only detect an electron-neutrino, capable of leading to a nuclear transmutation of chlorine into argon, it seemed possible that the missing neutrinos turned into other types. (As it turned out, neutrinos oscillate inside the Sun, and not on their way to Earth).
The only way to test this was to create a detector that worked for all three types of neutrinos. Since the 1990s, Arthur MacDonald of Queen's University in Ontario has led the team to do this at a mine in Sudbury, Ontario. The plant contained tons of heavy water, loaned by the Canadian government. Heavy water is a rare but naturally occurring form of water in which hydrogen, which contains one proton, is replaced by its heavier isotope deuterium, which contains a proton and a neutron. The Canadian government stockpiled heavy water because it is used as a coolant in nuclear reactors. All three types of neutrinos could destroy deuterium to form a proton and a neutron, and the neutrons were then counted. The detector recorded about three times the number of particles compared to Davis - exactly the number that was predicted the best models The sun. This made it possible to assume that the electron-neutrino can oscillate into other types of it.
Around the same time, Takaaki Kajita of the University of Tokyo was conducting another remarkable experiment. A detector installed in a mine in Japan recorded neutrinos coming not from the interior of the sun, but from the upper atmosphere. When cosmic ray protons collide with the atmosphere, showers of other particles, including muonic neutrinos, are formed. In the mine, they turned hydrogen nuclei into muons. Kajita's detector could observe particles coming in two directions. Some fell from above, coming from the atmosphere, while others moved from below. The number of particles was different, which indicated their different nature - they were at different points of their oscillatory cycles.
This is all exotic and surprising, but why are neutrino oscillations and masses attracting so much attention? The reason is simple. In the standard model of particle physics, developed over the past fifty years of the twentieth century, which correctly described all other observations in accelerators and other experiments, neutrinos were supposed to be massless. The discovery of neutrino mass suggests that something is missing. The standard model is not complete. The missing elements are yet to be discovered - with the help of the Large Hadron Collider or another, not yet created machine.
The speed of light is one of the universal physical constants, it does not depend on the choice of an inertial frame of reference and describes the properties of space-time as a whole. The speed of light in a vacuum is 299,792,458 meters per second, and this is the limiting speed of particle movement and propagation of interactions. This is how school books on physics teach us. You can also remember that the mass of the body is just not constant and as the speed approaches the speed of light tends to infinity. That is why photons move at the speed of light - particles without mass, and particles with mass are much more difficult.
However, the international team of scientists of the large-scale experiment OPERA, located near Rome, is ready to argue with the elementary truth.
He managed to find neutrinos, which, as shown by experiments, move at a speed greater than the speed of light,
reports the press service of the European Organization for Nuclear Research (CERN).
The OPERA (Oscillation Project with Emulsion-tRacking Apparatus) experiment studies the most inert particles in the Universe - neutrinos. They are so inert that they can fly through the entire globe, stars and planets, and in order for them to hit an iron barrier, the size of this barrier must be from the Sun to Jupiter. Every second, about 10 14 neutrinos emitted by the Sun pass through the body of every person on Earth. The probability that at least one of them will hit the human tissue throughout his life tends to zero. For these reasons, it is extremely difficult to register and study neutrinos. The laboratories that do this are deep under the mountains and even under the ice of Antarctica.
OPERA receives a neutrino beam from CERN, where the Large Hadron Collider is located. Its "little brother" - the superproton synchrotron (SPS) - directs the beam directly underground towards Rome. The resulting neutrino beam passes through the thickness of the earth's crust, thereby clearing itself of other particles that the material of the crust retains, and goes straight to the laboratory in Gran Sasso, sheltered under 1200 m of the rock.
The underground path of 732 km is covered by neutrinos in 2.5 milliseconds.
The detector of the OPERA project, consisting of about 150 thousand elements and weighing 1300 tons, "catches" neutrinos and studies them. In particular, the main goal is to study the so-called neutrino oscillations - transitions from one type of neutrino to another.
The stunning results of exceeding the speed of light are backed up by serious statistics: the laboratory in Gran Sasso observed about 15 thousand neutrinos. Scientists have found that
neutrinos move at a speed 20 ppm faster than the speed of light - the "infallible" speed limit.
This result came as a surprise to them; its explanation has not yet been proposed. Naturally, to refute or confirm it requires independent experiments conducted by other groups on other equipment - this principle of "double-blind control" is implemented at the Large Hadron Collider CERN. The OPERA Collaboration immediately published its results to enable colleagues around the world to verify them. Detailed description works available on the preprint site Arxiv.Org.
The official presentation of the results will take place today at a seminar at CERN at 18.00 Moscow time, online streaming.
“This data came as a complete surprise. After months of collecting, analyzing and cleaning data, as well as cross-checking, we did not find any possible source of system error in the data processing algorithm or in the detector. Therefore, we publish our results, continue to work, and also hope that independent measurements by other groups will help to understand the nature of this observation, "said the head of the OPERA experiment, Antonio Ereditato from the University of Bern, quoted by the press service of CERN.
“When experimental scientists discover an implausible result and cannot find an artifact that would explain it, they turn to their colleagues from other groups to begin a broader investigation of the issue. This is a good scientific tradition and the OPERA collaboration is now following it.
If the observations of exceeding the speed of light are confirmed, this could change our understanding of physics, but we must make sure that they have no other, more commonplace explanation.
This is what independent experiments are for, ”said Sergio Bertolucci, CERN Scientific Director.
OPERA's measurements are extremely accurate. Thus, the distance from the point of neutrino launch to the point of their registration (more than 730 km) is known with an accuracy of 20 cm, and the time of flight is measured with an accuracy of 10 nanoseconds.
The OPERA experiment has been running since 2006. About 200 physicists from 36 institutes and 13 countries, including Russia, take part in it.
