From the point of view of the entire experience of theoretical physics, this situation also looks abnormal. Physicists are trying to figure out if there might be some mechanism that naturally leads to such a spread. The Standard Model will not help here, but in some non-standard theories, a similar mass hierarchy may arise.
The Standard Model, as it was originally built, requires neutrinos to be strictly massless. However, it has been experimentally proven that neutrinos have a mass, albeit very small. In addition, neutrinos very actively mix with each other, constantly flowing from one type to another. All this suggests that the masses and mixing of neutrinos is not due to the Higgs mechanism, but due to a phenomenon of some other nature. Again, there are no such phenomena in the Standard Model, but there are plenty of such mechanisms among the various versions of New Physics.
In astrophysics, it is now generally accepted that in the Universe, in addition to ordinary matter in the form of stars, planets, gas and dust clouds, black holes, neutrinos, etc., there are also particles of a completely different nature, which we cannot see in any range of electromagnetic waves. These are particles of dark matter, about which nothing is known now, except for the fact that they move at low speeds and practically do not interact with radiation and ordinary matter. There is not a single particle in the Standard Model suitable for this role. However, candidate dark matter particles are found among theories outside the Standard Model.
Apparently, the observed part of the Universe consists almost entirely of matter – there are no separate planets, stars, galaxies made of antimatter. Such an imbalance of matter over antimatter should have arisen dynamically at the earliest stages of the evolution of the Universe. However, calculations have shown that the Standard Model is incapable of generating the necessary imbalance. In fact, the very existence of the world as we see it speaks of the insufficiency of the Standard Model.
There are a huge number of theoretical models that are not prohibited by the experimental data that exist so far and which give quite clear predictions for the LHC. These theories can include new particles, new interactions, or new dynamical phenomena with already known particles. A fairly detailed list of such theories was given on the page Beyond the Standard Model.
Some of these models are considered prime candidates for a deeper theory to replace the Standard Model; others are perceived by most physicists as explicitly exotic. Nevertheless, regardless of the level of exoticism, the predictions of such theories will be tested at the Large Hadron Collider (a separate page is devoted to the search for supersymmetry at the LHC).
There are two main ways to test the predictions of new theories in particle collisions at colliders:
Direct way: directly generate new particles in a sufficiently high-energy collision. Indirect way: notice the deviation from the predictions of the Standard Model when scattering ordinary particles.
It is worth emphasizing that in the overwhelming majority of theories, new particles are either unstable or invisible to the detector. Therefore, both direct and indirect methods boil down to a careful study of the processes of creation of ordinary particles and checking whether the Standard Model can describe them.
Which processes you need to pay attention to depends on the specific models. However, many of them have common features that distinguish them from the Standard Model. Listed below are some of the more common types of checks that are used when looking for effects outside the Standard Model.
All particles of the Standard Model, with the exception of neutrinos, are visible in detectors, which means that their momenta can be measured. Since the protons collide along the axis of the accelerating tube, the total transverse momentum of all final particles should be practically zero. If the detector “sees” a strong uncompensated transverse momentum and if it cannot be written off as neutrinos, this may be evidence that a new particle, not predicted by the Standard Model, was born and flew away in the collision.
Most of the elementary particles that physicists are really interested in (including hypothetical new particles) are very unstable and decay into more familiar particles before they reach the detector. But exactly the same set of registered particles can be born on its own, without an intermediate stage. As a result, physicists face a difficult task: having a set of particles registered by the detector, try to find out their origin.
An important property of the quantum world is that this can hardly ever be done for each specific particle collision event. Physicists extract such information only by accumulating many events of the same type and carrying out their statistical processing (for an example, see the article Anatomy of one news).
The key kinematic characteristic that helps to know about the intermediate stages in the creation of particles is their invariant mass. Relatively speaking, this is the mass that a heavy particle should have in order to generate a given pair of particles with just such energies and momenta during decay. In principle, the invariant mass can be calculated for any pair of particles – it does not matter whether they were obtained as a result of the decay of some common initial particle or not. If not, then the distribution over this invariant mass will be smooth, if yes, then an explicit peak corresponding to the parent particle will be seen in this distribution. This is how an unstable particle can be seen by its decay products.
Fig. 1. Distribution over the invariant mass of muon pairs in the region up to 150 GeV. Image from twiki.cern.ch
In fig. 1 shows the invariant mass distribution of a muon – anti-muon pair in the range from 0.5 GeV to about 150 GeV. This 2010 data shows several distinct peaks corresponding to the known particles of the Standard Model (a variety of hadrons and the Z-boson). If such a peak is found at even higher mass values, it will be possible to talk about the discovery of a new particle that is not included in the Standard Model.
Fig. 2. Distribution over the invariant mass of muon pairs in the region up to 2 TeV. The multi-colored histogram shows the contributions of different processes in the Standard Model; their sum describes well the data of the ATLAS detector (black dots). The multicolored broken lines in the region above 1000 GeV show peaks that could cause hypothetical Z’-bosons with masses of 1 to 1.5 TeV in the data. Image from a talk by Tommaso Lari. Recent results from New Physics Searches in ATLAS (PDF, 13 MB)
For example, in Fig. 2 shows the same distribution, but only in the region up to 2 TeV. This graph already shows the data of the ATLAS detector for the first months of 2011 and they extend to values of almost 700 GeV. They are well described by a solid black histogram that summarizes the contributions of all the processes of the Standard Model. Colored histograms in the region above 1 TeV show how the data should go if a hypothetical Z’-boson with a mass of 1 to 1.5 TeV exists in nature; if not, then the data should still go down following the black histogram.
In a standard hard collision, only a small number (two, three, four) of hard objects (hadronic jets or leptons with a large transverse momentum) are born. The probability that in a single collision due to standard processes, say, a dozen of such objects will be born at once is very small.
Fig. 3. A candidate black hole event recorded by the CMS detector on April 23, 2011. Shown here is the end view of the detector. Separate arcs are tracks of charged particles in a track detector, blue and red histograms in a circle show the energy release in calorimeters. This particular event had an anomalously large number of leptons and hadronic jets with high transverse momentum. For the avoidance of misunderstanding, let us emphasize that this event is called a “black hole candidate” only because it passed the selection criteria established in a particular analysis. Physicists do not at all claim that there really was a process of birth and decay of a black hole. Image from the CMS collaboration article
This probability can rise sharply in some exotic theories. For example, the birth and decay of microscopic black holes is precisely characterized by an anomalously large number of particles with significant transverse momenta. In fig. 3 shows an example of an event registered on April 23, 2011 by the CMS detector, in which ten jets and leptons with a large transverse momentum were born at once. If there were significantly more such black hole candidate events than expected in the Standard Model, one could seriously talk about the discovery of microscopic black holes.
ATLAS Exotics Public Results and CMS Exotica Public Physics Results – pages with all the public results of ATLAS and CMS collaborations on testing exotic theories. Theorists systematize the possible manifestations of new physics at the LHC // “Elements”, 17.05.2011.”
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Year of adoption – 1940Wingspan – 10.0 mLength – 8.48 mHeight – 1.70 mWing area – 17.15 sq. mEmpty aircraft weight – 2410 kgNormal takeoff weight – 2700 kgPower – 1180 hp. from.Maximum speed at the ground – 531 km / hMaximum speed at altitude – 592 km / hPractical range – 850 kmMaximum rate of climb – 926 m / minService ceiling – 10,000 mCrew – 1 person.
Known for:in the three planes – along with the German 123helpme.me Messerschmitt and the English Spitfire – the Yak-1 was a worthy opponent of one and an ally of the other; this explains its widespread use on the fronts of the Great Patriotic War. The success of the project is explained by the careful choice of aircraft aerodynamics and balance of maneuverability and speed of the aircraft, in contrast to the less successful project of NN Polikarpov “I-16″, in which preference was given to maneuverability.
Armament: one 12.7-mm UBS machine gun, or one 20-mm ShVAK cannon and two 7.62-mm ShKAS machine guns, 200 kg of bombs.
UBS – universal belt machine gun Berezina synchronous with a rate of 800 rounds per minute.ShVAK – large-caliber aviation gun of Shpitalny-Vladimirov (caliber 20 mm, rate of fire 800 rounds per minute).ShKAS – Shpitalny-Komaritsky aircraft rapid-fire machine gun (caliber 7.62 mm, rate of fire 1800 rounds per minute).
In the creative competition of design bureaus that developed new fighters at the end of the 30s, the team headed by A.S. Yakovlev achieved great success. The experimental I-26 fighter created by him successfully passed the tests and under the Yak-1 brand was accepted into mass production. The Yak-1 is a low-wing aircraft, one of the lightest fighters of those years.
Low-wing – an aircraft with a lower wing, in contrast to the center section – with a wing located along the axis of the fuselage and upper wing – with a wing located in the upper part of the aircraft.
The Yak-1M (modernized) was the lightest and most maneuverable fighter in the world for its time. It embodied the entire experience of the design bureau’s design work on the Yak fighters of the previous types. The aircraft of the A.S. Yakovlev design bureau – Yak-1, Yak-3, Yak-7, Yak-9 – constituted the main fleet of fighter aircraft during the Great Patriotic War. Their distinctive qualities were less weight than other machines of this purpose, good stability and ease of piloting. Until the end of the war, the factories supplied the front with more than 36 thousand Yak aircraft of various modifications – from Yak-1 to Yak-9DD.
Next: Best Fighter of the Battle of Britain in 1940 Supermarine Spitfire Mk.V (UK)
nearenergy E – from 3.3 eVtemperature T – from 8 thousand Kfrequency ν (nu) – from 8 1014 Hzwavelength λ (lambda) – up to 380 nm
vacuumE – from 6 eVT – from 14 thousand Kν – from 1.5 1015 Hzλ – up to 200 nm
The ultraviolet range of electromagnetic radiation is located beyond the violet (shortwave) edge of the visible spectrum.