1 elementary parts. Elementary particles. Budova and the power of elementary particles
Further penetration of the microworld is associated with the transition from the level of atoms to the level of elementary particles. This is an elementary part of the XIX century. there was a hidden electron, and in the first decade of the 20th century. – photon, proton, positron and neutron.
After another light war, with the advent of modern experimental technology, and before the hard work of those who create minds of high energies and great fluids, the foundation of a great cost was established and elementary particles – over 300. Among them are both experimentally detected and theoretically calculated, including resonances, quarks and virtual particles.
Term elementary part Initially meaning the simplest, the parts that lie at the basis of any material creations are not yet laid out. Later physicists became aware of the cleverness of the term “elementary” of microobjects. There is no longer any doubt that the particles form a different structure, aka, prote, as it is called, which has historically formed, and continues to exist.
The main characteristics of elementary particles are mass, charge, average life, spin and quantum numbers.
Rest assured Masu Elementary particles are identified by their relation to the mass of the electron. Elementary particles appear that do not disturb the peace of the mass, - photoni. Other parts, as indicated by this symbol, are divided into leptoni– light parts (electron and neutrino); mezzanine- Middle parts with a mass between one and a thousand electron masses; baryons- important parts, whose mass moves a thousand electrons and up to a warehouse that includes protons, neutrons, hyperons and many resonances.
Electric charge This is another important characteristic of elementary particles. All visible particles carry a positive, negative or zero charge. The skin particles, in addition to the photon and two mesons, resemble antiparticles with the same charge. Around 1963–1964. a hypothesis about sleep was established quarks- We fire a shotgun with an electric charge. This hypothesis has not yet been confirmed experimentally.
An hour to live the particles are divided into stable і unstable . There are five stable particles: a photon, two types of neutrinos, an electron and a proton. The most stable particles play the most important role in the macrobody structure. All other parts are unstable, the smell lasts for about 10-10-10-24 s, after which they disintegrate. Elementary particles from the average hour of life 10 –23 –10 –22 s are called resonances. After a short hour of life, the stench disintegrates even before the atom or nucleus is removed. Resonance factors are calculated theoretically; they cannot be recorded in real experiments.
Regardless of the weight and time of life, elementary particles are described in the same terms that have no analogues in classical physics: concepts back . The spin is called the power moment of the momentum of the particle, not related to its displacement. Spin is characterized spin quantum number s, as you can fill up (±1) or additional (±1/2) values. Pieces with a whole spin - bosoni, with a smile - fermioni. Electrons are transferred to fermions. In accordance with the Pauli principle, an atom cannot have more than one electron with the same set of quantum numbers n,m,l,s. p align="justify">Electrons, as indicated by Wil's functions with the same number, are even close to the energies and create the electron shell in the atom. The sub-shells in the number mean the “subshell”, other quantum numbers mean the replacements, about which it was said above.
The characteristics of elementary particles have one more important phenomenon mutual relations. As was stated earlier, it is clear that there are types of interactions between elementary particles: gravitational,weakling,electromagneticі stronger(nuclear).
All the parts that keep us calm ( m 0), take part from gravitational interaction, charging from electromagnetic interaction. Leptons also take part in weak interactions. Hadrons take part in all four fundamental interactions.
According to quantum field theory, everything interacts in a constant exchange virtual particles then the particles, the origin of which can only be judged indirectly, by their manifestations through certain secondary effects ( real parts can be easily fixed with additional devices).
It turns out that all types of interactions - gravitational, electromagnetic, strong and weak - are of calibrated nature and are described by calibrated symmetries. Then all mutual interactions are formed “from one blank.” This gives us hope that it will be possible to find “a single key to all the locks” and describe the evolution of the Universe, represented by a single supersymmetric superfield, in which there is a relationship between types The same between different parts of speech and field quanta has not yet been detected.
There are no methods for classifying elementary particles. So, for example, the particles are divided into fermions (Fermi-particles) - particles of speech and bosons (Bose-particles) - quanta fields.
Using a different approach, the particles are divided into 4 classes: photons, leptons, mesons, baryons.
Photoni (Electromagnetic field quanta) take part in electromagnetic interactions, but do not have strong, weak, gravitational interactions.
Leptoni they took away their name from the Greek word leptos- Easy. Particles are conveyed to them that do not undergo strong interactions between muons (μ - , μ +), electrons (e - , e +), electron neutrinos (ve - , e +) and muon neutrinos (v - m, v + m). All leptons have a spin equal to ½, and also fermions. All leptons interact weakly with each other. Those of them that carry an electric charge (both muons and electrons) also carry electromagnetic interactions.
Mesoni - Unstable particles that interact strongly do not carry the so-called baryon charge. Stay up to date with them R-mesoni or pivonia (π + , π - , π 0), Before-mesoni, or kaoni (K +, K -, K 0), Qia-mesoni (η) . Masa Before-mesons become ~970me (494 MeV for charged and 498 MeV for neutral Before-mesons). Hour of life Before-meson has a value of the order of 10 -8 s. The stench dissolves with light I- mesons and leptons or only leptons. Masa Qia-mesons is equal to 549 MeV (1074mе), the hour of life is about 10 -19 s. Qia-mesons decay due to the creation of π-mesons and γ-photons. In addition to leptons, mesons have not only a weak interaction (and, because they are charged, electromagnetic), but also a strong interaction, which manifests itself when they interact with each other, as well as when And between mesons and baryons. The spin of all mesons is equal to zero, which means they are bosons.
Class baryons combines nucleons (p, n) and unstable particles with a mass greater than the mass of nucleons, which are called hyperons. All baryons interact strongly and, therefore, actively interact with atomic nuclei. The spin of all baryons is equal to ½, so baryons are fermions. Blame the proton, all baryons are unstable. When baryons decay, a baryon becomes bound together with other particles. This pattern is one of the manifestations baryon charge conservation law.
A large number of strongly interacting short-lived particles, which were given the name resonances . These particles are resonant units created by two or a great number of elementary particles. The hour of life of resonances becomes deprived ~ 10 -23 -10 -22 s.
Elementary particles, as well as folded microparticles, are made to protect against these traces, which are lost when passing through the river. The nature of the traces allows us to judge the sign of the charge of the particle, its energy, momentum, etc. The charges of the particle cause the ionization of molecules on its surface. Neutral particles do not leave traces, but traces may appear at the moment of disintegration on the charged particle or at the moment of contact with the nucleus. Also, the presence of neutral particles is also revealed by the ionization caused by the charged particles generated by them.
Parts and anti-parts. U 1928 r. The English physicist P. Dirac was able to discover a relativistic quantum-mechanical basis for the electron, from which a number of miracles emerge. From this point of view, by natural order, without any additional assumptions, we can derive the spin and numerical value of the magnetic moment of the electron. Thus, it was understood that spin is both quantum and relativistic in magnitude. Ale tsim does not exhaust the significance of Dirac’s jealousy. It also allowed the transfer of the electron antiparticle – positron. From the level of Dirac, the full energy of the free electron comes out as positive and negative values. The research shows that for a given particle impulse, a solution can be found that corresponds to the energies: .
Between the greatest negative energy (– m e h 2) with the least positive energy (+ m e c 2) This is the range of energy values that can be realized. The width of this interval is equal to 2 m e h 2. Now, there are two areas of power energy values: one begins with + m e h 2 and extends to +∞, the other begins with – m e h 2 і will reach –∞.
A part with negative energy is guilty of the mother’s extreme power. Moving into the stage with less energy (that is, with a module that is increasing, negative energy), she could see the energy, let’s say, in the appearance of a prominence, and, moreover, fragments | E| Without any exception, a portion of negative energy could produce an infinitely large amount of energy. This approach can be taken in the next step: from a relationship E=m e h 2 indicates that a particle with negative energy will have a negative mass. Under the action of galmic force, a part with a negative mass is obliged not to comply, but to grieve, acting over the force that galms, the infinitely large number of robots. Considering this difficult issue, one would like to know that negative energy needs to be turned off in order to lead to absurd results. However, it would be great to follow the fundamental principles of quantum mechanics. So Dirac chose a different path. Having realized that the transitions of electrons from the surface with negative energy, there is no reason to worry about this because all the elements with negative energy are already occupied by electrons. 
According to Dirac, a vacuum is such a state in which all levels of negative energy are populated by electrons, and those with positive energy are free. The fragments will all, without blame, occupy the plains that lie below the buried smudge; electrons on these plains do not show themselves in any way. If one of the electrons, which is on the negative levels, will reveal energy E≥ 2m e h 2 Then this electron goes into the state with positive energy and behaves like a piece with a positive mass and a negative charge. The first particle from the theoretically transferred particles is called a positron. When a positron meets an electron, the stench annihilates (disappears) - the electron moves from a positive level to a negative vacant one. The energy that shows the differences between these two countries appears to be different. In Fig. 4, arrow 1 depicts the process of creation of an electron-positron pair, and arrow 2 – their annihilation. The term “anihilation” is not meant to be taken literally. In essence, what is happening is not the destruction, but the transformation of some particles (electron and positron) into others (γ-photons).
Find particles that are identical to their antiparticles (so that you don’t mess with the antiparticles). Such parts are called absolutely neutral. Before them lie a photon, a π 0 meson and an η meson. The particles, identical with their antiparticles, are not created before annihilation. This, however, does not mean that the stench from the fire cannot transform into other parts.
How to assign a baryon charge (or baryon number) to baryons (both nucleons and hyperons) U= +1, antibaryon – baryon charge U= –1, and the number of particles is the baryon charge U= 0, then all processes that occur with the participation of baryons and antibaryons will be characterized by conservation of baryon charge, just as processes are characterized by conservation of electric charge. The law of conservation of baryon charge determines the stability of every baryon - the proton. The transformation of all quantities that describe a physical system, in which all particles are replaced by antiparticles (for example, electrons with protons, and protons with electrons, etc.), is called the charge of acquisition.
Wonderful parts.Before-mesoni and hyperoni were found in the warehouse of space exchanges for the cob of the 50s. XX century Starting from 1953 They are dominated by haste. The behavior of these particles was so unusual that the stench was called marvelous. The innocence of the behavior of the strange particles was reflected in the fact that the stench was heard clearly due to the strong interaction with a characteristic time of about 10 -23 s, and their life was around 10 -8 -10 -10 s. The remaining situation indicated that the disintegration of particles was due to weak interactions. It was hard to understand why it was so strange to live so long. The fragments both in the population and in the disintegration of the λ-hyperon take part in the same particles (π-mesons and protons), it was surprising that the fluidity (or homogeneity) of both deposition processes is different. Further research showed that strange parts are found in pairs. This led to the idea that strong interactions cannot play a role in the disintegration of particles because they require the presence of two different particles. For these same reasons, it is impossible to single out the creation of wondrous particles.
To explain the isolation of a single generation of wonderful particles, M. Gell-Mann and K. Nishijima introduced a new quantum number, the total value of which may, in their opinion, be preserved in strong interactions. Tse quantum number S named marvelous parts. With weak interactions, the divin can save herself. This is attributed to strongly interacting particles – mesons and baryons.
Neutrino. Neutrino is a single particle that does not take part in either strong or electromagnetic interactions. Including gravitational interactions, which share the fate of all parts, neutrinos can take part only in weak interactions.
For a long time it was lost in the incomprehensible matter of how neutrinos differ from antineutrinos. In accordance with the law of conservation of combined pairings, it is possible to confirm this nutrition: they are divided by spirality. Pid spirality It is understood that there is no correspondence between the directions of the impulse R and back S parts. Spirality is considered positive, since the spin and impulse travel in the same direction. Who's going to get a piece of it right away ( R) and straight “wrap”, which indicates the back, apply the right screw. With prolonged straightening of the back and impulses, the spirality will be negative (the forward rotation and “wrapping” are created by the left screw). Consistent with the theory of late neutrinos advanced by Yang, Li, Landau and Salam, all neutrinos found in nature, regardless of the way they are produced, are always lately polarized (then their spin is directing parallel or antiparallel to the impulse) R). Neutrinos fly negative(left) spirality (this is evidenced by the direct relationship Sі R, shown in Fig. 5 (b), antineutrino - positive (right) helicity (a). Well, spirality is what separates neutrinos from antineutrinos.
Small 5. Scheme of the helicity of elementary particles
Systematics of elementary particles. Regularities in the world of elementary particles can be formulated as laws of conservation. There are already many such laws that have accumulated. Their actions appear not to be accurate, but rather close. The law of conservation of skin determines the fundamental symmetry of the system. Laws of impulse conservation R, moment of impulse L that energy E depict the power of symmetry and space at the same time: saving Eє after the same time, saving R furnished with uniform space, and saving L- I'm so isotropic. The law of preserving the pairing of knitting due to the symmetry between right and left ( R-Invariance). The symmetry of charge pairing (the symmetry of particles and antiparticles) should be achieved until the charge pairing is preserved ( Z-Invariance). The laws of conservation of electric, baryon and lepton charges express a special symmetry. Z-functions. Find out that the law of conservation of isotopic spin promotes the isotropy of the isotopic space. Failure to comply with one of the laws of saving means a violation in this relationship of a certain type of symmetry.
The world of elementary particles has a rule: everything is permitted as long as it is not prohibited by the laws of conservation. The rest play the role of exclusion rules that regulate the interaction of particles. What is important to us is the laws of conservation of energy, impulse and electric charge. These three laws explain the stability of the electron. This saving of energy and momentum increases, so that the total mass of the calm decomposition products is responsible for less than the mass of the calm parts that disintegrate. Then, the electron could decay from neutrinos and photons. All the particles are electrically neutral. It turns out that the electron simply has no one to transfer its electrical charge to, so it is stable.
Quarks. Pieces called elementary have become so abundant that serious doubts have arisen about their elementarity. The skin of strongly interacting particles is characterized by three independent additive quantum numbers: charge Q, hypercharge U and baryon charge U. In connection with this, the hypothesis is that this part is caused by three fundamental parts - the carriers of these charges. Born in 1964 Gell-Mann and, more recently, the Swiss physicist Zweig proposed a hypothesis according to which all elementary particles are made up of three particles called quarks. These particles are assigned shot quantum numbers, zocrema, electric charge, which is equal to +⅔; -⅓; +⅓ suitable for skin from three quarks. Qi quarks are designated by letters U,D,S. Cream of quarks, antiquarks are visible ( u,d, S). As of today, there are 12 quarks - 6 quarks and 6 antiquarks. Mesons are created from a quark-antiquark pair, and baryons are created from three quarks. So, for example, a proton and a neutron are composed of three quarks, which makes the proton or neutron barless. Three charges of strong interactions - red ( R), Zhovtiy ( Y) that green ( G).
The skin quark is assigned a new magnetic moment (µV), the value of which is not specified in the theory. Fractures formed on the base of such an alloy give the proton a value for the magnetic moment p = μ kv, and for a neutron μ n = – ⅔μ sq.
Thus, for the development of magnetic moments, the values μ p are obtained / μ n = –⅔, which miraculously fits with experimental values.
Basically, the color of the quark (similar to the sign of the electric charge) begins to express the importance of power, which means the mutual gravity and distribution of quarks. By analogy with quanta of fields of various interactions (photons in electromagnetic interactions, R- mesons in strong interactions, then) particles-carriers of interaction between quarks were introduced. These parts were named gluons. They transfer color from one quark to another, as a result of which the quarks are eliminated at once. The physics of quarks formulated the confinement hypothesis (in English). confinements- Full of quarks, which makes it impossible to separate a quark from the whole. It can only be considered as an element of the whole. The origin of quarks as real particles in physics is reliably grounded.
The idea of quarks became even more fruitful. She allowed us to systematize already known parts, and to introduce new ones. The situation that has developed in the physics of elementary particles, one can guess the situation that has developed in the physics of the atom after its discovery in 1869. D.I. Mendelev's periodic law. Although the essence of this law was explained approximately 60 years after the creation of quantum mechanics, it was possible to systematize the known chemical elements at that time and, in addition, calling for new elements before transferring and their authorities. So physicists themselves began to systematize elementary particles, and the fragmentation of systematics in a series of episodes allowed the creation of new particles and the transfer of their power.
Well, quarks and leptons are considered truly elementary; There are 12, and together with the antiquities – 24. In addition, there are particles that will ensure fundamental interactions (interaction quanta). Number of particles 13: graviton, photon, W± - і Z-particles of 8 gluons.
Basic theories of elementary particles cannot indicate what is in the row: atoms, nuclei, hadrons, quarks. In this series, the skin folding material structure includes more than just a storage part. Obviously, we can’t chew on it so endlessly. It has been assumed that descriptions of material structures are based on objects of another nature. It is shown that such objects can be not point-like, but extended, even though they are extremely small (~ 10-33 cm) illuminated, called super strings. The idea described has not been implemented in our vast world. This area of physics is already extremely abstract, and it is even important to select basic models that will help to simplify the understanding of the ideas underlying the theories of elementary particles. It is no less true that these theories allow physicists to determine the mutual transformation and interintelligence of the “most elementary” microobjects, their connections with the authorities of the vast world. The most promising person is so called M-theory (M – view mystery- Riddle, secret place). Vaughn operates twelve-dimensional space . I guess, when we move to the worldly world that we have completely captured, all the “zavі” of the world “burn out.” M-theory is still the only theory that makes it possible to know several fundamental interactions down to one - the so-called Superpower. It is also important that the theory allows for the emergence of different worlds and establishes the minds that will ensure the guilt of our world. M-theory is not yet sufficiently fragmented. It's important that it's residual "theory of everything" based on M-theory will be developed in the 21st century.
Closely related to the physics of the atomic nucleus is the physics of elementary particles. This area of modern science is based on quantum phenomena and in its development further and further penetrates into the depths of matter, revealing the mysterious light of its fundamental principles. In the physics of elementary parts, the role of theory is extremely important. In view of the impossibility of direct monitoring of such material objects, their images are associated with mathematical equations, with the protective and global rules they impose.
Behind the most important elementary particles are the primary, uncomplicated lights, including, after all, all matter is formed. In fact, this term is used in a broader sense - to designate a large group of microparticles of matter that are not structurally united in the nucleus and atom. Most objects for studying the physics of elementary particles do not correspond to a strict level of elementarity, other than storage systems. Therefore, the parts that satisfy everyone are usually called truly elementary.
The first elementary part, discovered in the process of implantation of the microsphere since the end of the 19th century, is the electron. Let's come the discovered proton (1919), then came the neutron, discovered in 1932. The origin of the positron was theoretically transferred by P. Dirac in 1931, and in 1932. This positively charged “twin” of the electron appears in cosmic exchanges. . The assumption about the existence of neutrinos in nature was raised by W. Pauli in 1930, and it was experimentally discovered only in 1953. At the warehouse of space exchanges in 1936. mu-mesons (muoni) were found - parts of both signs of electric charge with a mass of close to 200 mass electrons. In other respects, the powers of muons are very close to those of electrons and positrons. Same with space exchanges in 1947. There were clearly positive and negative pi-mesons, the origin of which was conveyed by the Japanese physicist Hideki Yukawa in 1935. It became clear that there is also a neutral pi-meson.
To the beginning of the 50s. it was open to a large group of people with even unusual authorities, which prompted them to be called “marvelous”. The first parts of this group were detected in cosmic exchanges, including K-mesons of both signs and K-hyperon (lambda-hyperon). It is significant that mesoni took their name from walnut. “middle, intermediate” through those that masses of first liquid particles of this type (pi-mesons, mu-mesons) form a mass between the mass of nucleons and electrons. Hyperoni derives its name from the Greek. “more, more”, the fragments of their mass transfer the mass to the nucleon. The new discoveries of elementary particles worked on the hasty charging of elementary particles, which became the main tool for the development of elementary particles.
So there was an antiproton, antineutron and low hyperons. At 60 rocks. It was revealed that there were a significant number of particles from very short periods of life, which were removed from the resonances. As it was understood, most of the visible elementary particles lie before the resonances. In the mid-70s. A new family of elementary particles was discovered, which received the romantic name “enchanted”, and at the beginning of the 80s - a family of “beautiful” particles and the so-called vector intermediate bosons. The discovery of these particles was a quick confirmation of the theory, based on the quark model of elementary particles, which transferred the origin of new particles long before detection.
Thus, within an hour after the discovery of the first elementary particle - the electron - in nature, almost 400 microparticles of matter were discovered, and the process of the discovery of new particles will continue. It turned out that the world of elementary particles of influence is even more complex, as the authorities are varied and often extremely disobedient.
All elementary particles are material creations of extremely small masses and sizes. Most of them have a mass on the order of that of a proton (~10 -24 r) and a size of about 10 -13 m. This indicates the quantum specificity of their behavior. What is important is the quantum power of all elementary particles (including the photon that lies before them) in the fact that the processes from it are revealed as the sequence of actions of their transformation and destruction (the creation of people is created and and when interacting with other particles). The processes involving elementary particles extend to all four types of fundamental interactions, strong, electromagnetic, weak and gravitational. Strong interaction between the bonds of nucleons in the atomic nucleus. Electromagnetic interaction ensures the bonding of electrons with nuclei in an atom, as well as the bonding of atoms in molecules. Weak interaction calls for, collapse, disintegration of quasi-stable (or long-lived) particles, which looms the hour of life between 10 -12 - 10 -14 s. Gravity interaction at distances characteristic of elementary particles of ~10 -13 cm, through a small amount of their mass, has an extremely low intensity, but may appear as an intensity at small distances. The intensity of interaction, strong, electromagnetic, weak and gravitational - at moderate energy of the processes appears to be 1, 10 -2, 10 -10, 10 -38. As the energy of the particles increases, their relationship changes.
Elementary particles are classified using different signs, and the need to say what is accepted by this classification is quite complicated.
It is important to divide the interactions between different types into two main groups: hadrons and leptons.
Adrons take part in all types of interactions, including strong ones. The stench took its name from the walnut. "great, strong."
Leptony does not take part in a strong interaction. Its name is to resemble a walnut. “light, thin”, fragments of the mass were known until the mid-70s. particles of this class were noticeably smaller than the masses of all other particles (except photons).
All baryons (a group of particles with a mass no less than the mass of a proton, so called from the Greek “important”) and mesons are carried to hadrons. The lightest baryon is the proton.
Leptons, electrons and positrons, muons of both signs, neutrinos of three types (light, electrically neutral parts, which are less likely to participate in weak and gravitational interactions). It is transmitted that neutrinos are widespread in nature, like photons, until the current light is produced without any other processes. The distinguishing feature of the neutrino is its great density that penetrates, especially at low energies. To complete the classification of the types of interactions, it should be noted that the photon takes part only in electromagnetic and gravitational interactions. In addition, similar to theoretical models aimed at combining all four types of interactions, there is a hypothetical part that transfers the gravitational field, which is called graviton. The peculiarity of graviton lies in the fact that it (consistent with the theory) takes part in the gravitational interaction. It is important to note that the theory connects with quantum processes of gravitational interaction two more hypothetical parts - gravitino and graviphoton. The experimental detection of gravitons, essentially gravitational vibration, is extremely difficult due to their extremely weak interaction with speech.
Over the course of life, elementary particles are divided into stable, quasi-stable and unstable (resonances).
Stable particles are the electron (at one hour of life t > 10 21 years), the proton (t > 10 31 years), the neutrino and the photon. Quasi-stable are considered particles that disintegrate due to electromagnetic and weak interactions, their life time t > 10 -20 s. Resonances are parts that fall apart as a result of strong interaction; the current hour of life is in the interval 10 -22 ^ 10 -24 s.
The most widespread is another type of fragmentation of elementary particles. Systems of particles with zero or zero spin are ordered by Bose-Einstein statistics, so such particles are usually called bosons. The totality of particles with a complete spin is described by Fermi-Dirac statistics, hence the name of such particles - fermions.
The elementary part of the skin is characterized by a distinct set of discrete physical quantities - quantum numbers. The essential characteristics for all particles are mass m, life hour t, spin J and electric charge Q. The spin of elementary particles increases to a value that is comparable to either a constant multiple of Planck. The electrical charges of the particles are entirely multiples of the charge of the electron, which is determined by the elementary electric charge.
In addition, elementary particles are further characterized by so-called internal quantum numbers. Leptons are assigned a specific lepton charge L = ±1, hadrons with a similar spin carry a baryon charge = ±1 (hadrons with B = 0 form a subgroup of mesons).
An important quantum characteristic of hadrons is the internal parity P, which takes a value of ±1 and emphasizes the power of the symmetry function of the spine part before spatial inversion (mirror imaging). Regardless of the lack of parity in weak interactions, particles with good accuracy acquire the values of internal parity, equal to either +1 or -1.
Hadrons, in addition, are divided into primary particles (proton, neutron, pi-mesons), primary particles (^-mesons, hyperons, and resonances), “enchanted” and “beautiful” particles. They are represented by special quantum numbers: divinity S, charm C and beauty b. These quantum numbers are introduced in a similar way to the quark model to understand the specific processes characteristic of these particles.
Among hadrons there are groups (homelands) of particles with similar masses, but with internal quantum numbers, and they are separated by an electric charge. Such groups are called isotopic multiplets and are characterized by a hidden quantum number - isotopic spin, which takes on, like the extreme spin, the same meaning.
What is the quark model of hadrons, which has already been thought of more than once?
The discovery of the regularity of grouping of hadrons in a multiplet served as the basis for the launch of special structural creations, including the origin of hadrons - quarks. Assuming the existence of such particles, it is important to consider what hadrons are and combinations of quarks. This is a funny and heuristically productive hypothesis that was hung in 1964. American physicist Murray Gell-Man. The essence of this was the assumption of the presence of three fundamental particles with a unique spin, which is the material for stimulating hadrons, u-, d- and s-quarks. Recently, on the basis of new experimental data, the quark model of boudo hadrons was replenished with two more quarks, “enchanted” (c) and “beautiful” (b). Respect for the possibility of founding other types of quarks. The remarkable peculiarity of quarks lies in the fact that they carry fractional values of electric and baryon charges, which do not converge in liquid particles. All experimental results of the implantation of elementary particles are used with the quark model.
According to the quark model, baryons are composed of three quarks, mesons are composed of a quark and an antiquark. The fragments of a baryon are a combination of three quarks in the same state that is protected by the Pauli principle (marvelous thing), the skin type (“flavor”) quark was assigned an additional internal quantum number “color”. A quark of the skin type ("flavor" - u, d, s, c, b) can be found in three "color" states. In connection with the various colors, the theory of strong interaction of quarks was called quantum chromodynamics (from the Greek “color”).
It can be noted that quarks are new elementary particles, and they pretend to be truly elementary particles for the hadronic form of matter. However, the problem of guarding free quarks and gluons remains unsolved. Regardless of systematic searches in cosmic exchanges, in high-energy rushes, it has not yet been possible to reveal them in the civilian world. Let us bear in mind that here physics has encountered a special phenomenon of nature - the so-called mornings of quarks.
On the right, there is serious theoretical and experimental evidence for the theory that the forces of interaction between quarks and the subsurface are not weakening. This means that the subset of quarks requires an infinitely large amount of energy, so that the appearance of quarks in a free state is impossible. This arrangement gives quarks the status of special structural units of speech. Perhaps, starting from quarks, it is fundamentally impossible to keep up with the steps of fragmentation of matter. The recognition of quarks as real objects of material light marks a striking outburst of the primacy of the idea of a fundamentally grounded material entity. There is a further review of the table of fundamental light constants, since the charge of a quark is less than the charge of a proton, and also an electron.
Beginning with the discovery of the positron, science began to work on particles of anti-speech. Today, it is obvious that for all elementary particles with non-zero values, we need one of the quantum numbers, such as electric charge Q, lepton charge L, baryon charge B, divinity S, charac- terity C and beauty b, there are antiparticles with the same values and , hour of life, spin, ale z protilegnymi signs of fortune-telling quantum numbers. The parts that are similar to their antiparticles are called truly neutral. The examples of truly neutral particles are a photon and one of the three pi-mesons (the other two are one to one particle and antiparticle).
The characteristic of the special part of the part of the anti -region ї ї ї ї їhiylyatsya at the zіtknnin, the Tobto mutual terms of the same parties to the vicunks of the Law of the Zberezhennya Energi, Impulsu, the Toshi charge. A typical application of steam annihilation is the process of transformation of an electron and its antiparticle - a positron - electromagnetic vibration (in photons and gamma rays). Annihilation of pairs occurs both in case of electromagnetic interaction and in case of strong interaction. At high energies, light particles can animate from the creation of more important particles - because the greater energy of the particles that animate exceeds the threshold of formation of important particles (equal to the sum of their energies at rest).
With strong and electromagnetic interactions, there is complete symmetry between particles and their antiparticles, i.e., all processes that occur between the first and possible in others. Therefore, antiprotons and antineutrons can dissolve the nuclei of atoms of anti-speech, i.e., from the anti-frequency, anti-speech can be generated in principle. The obvious culprit is nutrition: since the skin part contains an antiparticle, then why does the whole world have a daily purchase of anti-speech? It is true, about the presence of them in the All-World, to bring here “near” the All-World, one could judge from the intense annihilation of prominence, which comes to the Earth in the Galusia of a closed speech and an anti-speech. However, current astrophysics does not have data that would allow us to admit the presence of regions filled with anti-flux in the whole world.
How can the Universe choose between the evil speech and the evil anti-speech, wanting the laws of symmetry to be balanced? The reason for this phenomenon, which led to everything, was the very destruction of symmetry, so that fluctuations were not at the same level as the foundations of matter.
One is clear: Yakby did not blame the fluctuete, the share of the vibrant boule is dummy - the whole Mother of the Mother of the Wiggling of the Non -Chmari photons, Sho Zyavavilovili in the result of the ANIGILATSIA PARNOKI RUCHOVINI TA Antirechovini.
Currently, electrons have the same knowledge (div. below), as well as quarks internally. the structure has not been revealed, although it is theoretical. models, such as leptons and quarks, are generated from more fundamental points of light - preons (this term, however, is not yet generally accepted).
Historically first experimentally revealed e.h. there was an electron, a proton, and then a neutron. It seemed that the totality of these particles and the electron-magnetic quantum. The photon field is sufficient to awaken visible forms of speech (atoms and molecules). The reason for this approach was from protons, neutrons and electrons, and el.-magn. the field (photons) interacted between them. However, it was obvious that the world of settlements was much more complex. It was established that the skin part has its own, as it has no sign of charges (div. below); for particles with zero values of all charges, the antiparticle runs after the particle (example - photon). Further, with the development of experimental nuclear physics, there were still more than 300 particles left before the four (or seven) particles were re-arranged. It is possible to establish that most of these particles are made up of quarks, the number of which is more than 6 (or 12 in the case of antiquarks).
Another most important achievement of microworld physics was the discovery that E.H. Pritamanne yak el.-magn. mutualism. The study of atomic nuclei revealed that the forces that reduce protons and neutrons in the nucleus are electromagnetic.
Characteristic of nucleons (protons and neutrons in the nucleus), the interaction was not called strong. It appeared short-lived - on the rises r, What exceeds 10 -13 cm, the strong interaction is unimportantly small. However, when r Nuclear power). The instability of the neutron and many atomic nuclei indicated the emergence of another type of interaction, called weak. The three types of interaction between the elements, as well as the gravitational interaction, are drawn from the types of fundamental physics. mutual. The main idea is that there are 4 (or even 3) types of interactions: phenomena are of the same nature and can be described by a single principle.
Unified theory of weak and el.-magnetic mutual cooperation has already been initiated and confirmed by evidence; There are theoretical models that simultaneously describe all types of interactions (div.).
2. Classification of elementary particles
Table 1. Elementary parts ( Q- Electric. charge, L- Lepton charge, B- Baryon charge, S- Divinity, C- Charity).
| Section type | Symbol | Masa m, MeV | Spin, at od. |
Hour life, s |
Q | L | B | S | C |
| Leptoni | e- | 0,511 | 1/2 | align="absmiddle" width="65" height="15"> | -1 | 1 | 0 | 0 | 0 |
| stable 3) | 0 | ||||||||
| 105 | -1 | ||||||||
| stable 3) | 0 | ||||||||
| 1784 | -1 | ||||||||
| stable 3) | 0 | ||||||||
| Mesoni- carriers mutual relations |
0 | 1 | stable | 0 | 0 | 0 | 0 | 0 | |
| W | |||||||||
| Z 0 | 0 | ||||||||
| gluon 5) | 0 6) | stable 6) | 0 | ||||||
| Mesoni (hadroni) |
135 | 0 | 0 | 0 | 0 | 0 | 0 | ||
| 140 | +1 | 0 | 0 | ||||||
| K 0 | 498 | 0 | +1 | 0 | |||||
| K+ | 494 | +1 | +1 | 0 | |||||
| D0 | 1864 | 0 | 0 | +1 | |||||
| D+ | 1869 | ~ 10 -12 | +1 | 0 | +1 | ||||
| F+ | 2020 | +1 | -1 | +1 | |||||
| Barioni 8) (hadroni) | p | 938,3 | 1/2 | >10 38 | +1 | 0 | 1 | 0 | 0 |
| n | 939,6 | 900 | 0 | 0 | 0 | ||||
| 1115 | 0 | -1 | 0 | ||||||
| 1189 | +1 | -1 | 0 | ||||||
| 1192 | 0 | -1 | 0 | ||||||
| 1197 | -1 | -1 | 0 | ||||||
| 1315 | 0 | -2 | 0 | ||||||
| 1321 | -1 | -2 | 0 | ||||||
| 1672 | -1 | -3 | 0 | ||||||
| 2280 | ~ 10 -13 | +1 | 0 | 1 |
1) The number of particles placed in the table contains a large number of short-lived particles, i.e. resonances, which loom the hour of life ~ 10 -20 -10 -24 s. To guide particles, the table of particles does not indicate their antiparticles, which contain the same mass values, hour of life, and other signs of quantum numbers Q, L, B, S, C.
2) Vazhayut, scho, if special. there is no basis for this; perhaps, .
3) It is natural to realize that neutrinos are unstable, although their lifetime may be even longer.
4) Theoretically induced. assessment.
5) Gluon, as a free part, does not exist.
6) Theoretical assessment.
7) K 0 - i -mesons do not tarnish the hour of life.
8) Baryons of great importance are guilty C(up to 3), as well as with non-zero values Cі S overnight; phenomena meson (GeV), which has a quantum number ("beauty") that is not equal to zero, which is attributed b-Quark.
Depends on the nature of the interaction E.ch. Available on Dec. great groups (Table 1). e.h., in which the interaction is strong, sound. . Before the hadrons there are protons, neutrons and more important parts of hyperonium (all of them have a common name), as well as great substance. Parts that take part in strong interactions, sound. . In addition to electrons, there are two other charged leptons: the muon and the tau lepton (“important lepton”), which are 210 and 3600 times more massive than the electron. For a skin charge, the lepton is indicated by a neutral part - (electronic, muon or tau). The mass of neutrinos is equal to zero or even small. There are 6 (with 12 antiparticles) types of leptons. Neutral leptons share the same fate as weak interactions; charging - weak and electromagnetic. Neutral leptons, however, may have even less magnetism. moments. Adroni take the fate of the strong, the weak and the el.-magn. mutual relations. And, obviously, all parts interact gravitationally. Moreover, there are also particles - carriers of interaction: photon (carrier of electron-magnetic interaction), W- and Z0-bosons (carriers of weak interaction). It is important that there is a carrier of gravity. mutualism – graviton.
e.h. are characterized by their mass, electric charge, and the wetness of the hand.
The masses of the lightest particles (such as photons) are equal to zero, and the masses of the largest known particles exceed the mass of the proton 100 times. Electric charge E.h. є is a multiple of the charge of the electron. The number of particles is either complete (0, 1, 2, ...) - sometimes they are called bosons, or (1/2, 3/2, ...) - sometimes they are called fermions.
Leptons are assigned the so-called leptonium charge L, It is taken to be equal to +1 for particles and -1 for their antifrequencies. The introduced charge is ensured that in all processes that take place in a closed system, the number of leptons and antileptons is saved. In addition, the skin pair of leptons of water has its own special leptonic charge, apparently. The introduction of these charges is counteracted by the fact that, for example, an electron neutrino, colliding with a neutron, can produce an electron, rather than a muon chi-lepton. The values are equal to +1 for significant pairs of leptons and -1 of their antiparticles. However, the possibility is widely discussed that more neutrinos can later change their lepton charge, transforming into neutrinos of a different type (neutrino oscillations). As a result, different types of neutrinos produce different charges of leptons of different types.
Baryons, like leptons, are assigned their own baryon charge, which is conserved. B. The nature of the conservation of lepton and baryon charges remains unclear. It is necessary for those models of the great unification to prophesy that this is the preservation of phenomena. Let’s just get closer, if we want to reveal the possible destruction of the savings, perhaps, on the boundaries or beyond the boundaries of the knots. experimental feasibility. All we know are leptons and baryons. fermions. Mesons have neither baryon nor lepton charge and are phenomena. bosons. In addition, specific quantum numbers (charges) are assigned to hadrons, which are called divinity ( S), charm ( C) and the like, like, under the administration Bі L, are not saved in weak interactions, but are saved in strong and electromagnetic ones. Due to this, the lightest parts of the world, being unstable, may endure a long period of life on the scale of the world. (Div. Table 1), because Before their disintegration, a weak relationship may result.
3. Quark model of boudo-hadrons
All adrons, based on modern times. phenomena caused by the largest number of fundamental particles - quarks ( q). Like leptons, quarks are phenomena. fermions, their spin is equal to 1/2, electric. charge +2/3 and -1/3 (in one electron charge), charge of antiquarks -2/3 and +1/3, all quarks have barium charge B=1/3, leptonium charge L=0. Similarly, lepton quarks are also grouped in pairs. Moreover, there may be a quarklepton symmetry at work: each pair of leptons is represented by a pair of quarks (div. Table 2). Pairs (e,) are representative of quarks, which are designated (u, d). These are the lightest quarks, their mass is 5-10 MeV, their novelty, charm, etc. Such quantum numbers approach zero. Such quarks can produce nucleons, then. proton and neutron: p=( uud), n = ( udd). Dr. Possibly three of these quarks are also realized in nature, satisfying more important parts, for example. a particle with a spin of 3/2 and a mass of 1240 MeV. In a quark-antiquark pair, there will be mesons that are closely adjacent to the known mesons - meson: ), ) i , which is crazy i .
Four pieces ( u,d,,e) approve t.zv. first quark-lepton generation. Two more generations are visible ( c,s, ) that ( t,b,) (div. table 2) to remove more massive particles.
Table 2. Quarks and leptons.
| 1st generation | 2nd generation | 3rd generation | ||||||||||
| Appointment | u | d | e | c | s | t | b | |||||
| Electic charge at od. electron charge | +2/3 | -1/3 | 0 | -1 | +2/3 | -1/3 | 0 | -1 | +2/3 | -1/3 | 0 | -1 |
| Masa, MeV | 0,5 | 1200 | 150 | 105 | 1784 | |||||||
Obviously, it is not necessary in cosmology to talk about the prevalence of the next quark-lepton generations (division below). On the other hand, three generations of particles appear to be sufficient for theoretical an explanation of the importance of holy particles and antifrequencies. Skin of important quarks ( c,sі t,b) Volodya is similar to its quasi number, which is preserved. C, S or else T,B. Oskolki S sound divinity, and s-quark sound. marvelous; C sound charm, B- beauty, for T the term has not yet become. The parts that it took to enter the warehouse s-Quark, sound. marvelous. By theoretically replacing one, two and three quarks in a nucleon, it is possible to explain the origin of all these new baryons - hyperons (div. Table 1). Similarly, at the hour of replacement u- or d-quark in -meson on s-Quark is fashionable to distinguish phenomena in nature from the marvelous K-meson. So they themselves are wary of enchanted particles (with ) lurking around their warehouse h-Quark, etc. In principle, all six types of quarks can be connected with each other, but until now only some of them have been avoided. All open hadrons can be described as connected to six quarks.
Each quark has a quantum number, which is called a color. Color yavl. analogue of electric charge, even more foldable. The presence of color is explained by the strong interaction of quarks, like leptons, which do not change color.
In the same way that electric charges interact through photons, strong interaction carriers – gluons – interact with color charges. However, instead of a single photon, there are all different types of gluons. Dr. The real difference lies in the fact that the photon is not electrical. charge and therefore do not interact on their own, but gluons, bearing a color charge, interact one with one. Obviously, this is the reason for a fundamentally new phenomenon called the confinement of quarks. On the right is that, regardless of the great energy of the particles, accelerated in modern times. In a hurry, it is not possible to save quarks from the outside. The stench, perhaps, is present in nature beyond the appearance of quark-antiquark pairs (), three ( qqq) or more folding works, or obov'yazkovo such as electric. the charge of these objects was intact. All such objects carry a zero color charge. To put it simply, the reality of confinement lies ahead. When you try to remove a quark from a free station (to “pull” it from the hadron to reach a large stand, which gives it high energy), the strength of the field that is not compensated for the charge of the color of the quark appears so strong that the quark is responsible for With this energy, a pair emerges from the vacuum and the antiquark collapses together with the quark , which they are trying to overcome. As a result, it is not the quark that floats, but the storage part, which does not change the color. For these reasons, gluing can also be avoided in the wild. The phenomenon of confinement represents a small radius of strong interaction.
The field of physics of elementary particles, which involves the interaction of quarks and gluons, is called quantum chromodynamics. Quantum chromodynamics of phenomena. theory of strong interaction E.ch.
Thus, on the bitch. equal understanding of the elementarity of the fundamental storage materials of phenomena. 6 leptons (with 12 antiparticles), 6x3 = 18 quarks (with 36 antiparticles), as well as interaction carriers: strong - 8 gluons, electromagnetic - photon, weak - W- and Z 0 -bosons. Leptons and quarks have a spin of 1/2, and interaction carriers have a spin that is higher than 1, they are called vector bosons. The existence of all over-corrected particles is confirmed by experiment. In addition, this theory emphasizes the establishment of a scalar field that is constant throughout the entire space, in which different leptons and quarks interact in different ways, which means the importance of their mass. The quanta of the scalar field are new, transferred to the theory of E.H. zero spin. They are called Higgs bosons (after the English physicist P. Higgs, 1964, who introduced them to their origin). The number of Higgs bosons can reach Dec. tens. The interaction of W- and Z0-bosons with a scalar field determines the values. a lot of particles and a small radius of weak interactions. Higgs bosons have not yet been discovered. Moreover, low physics is important due to the fact that it is not necessary, but a complete theoretical scheme without Higgs bosons has not yet been found.
Grand unification models require the propagation of additional vector particles - carriers of the interaction between hadrons and leptons. The simplest version of such particles has 12 masses m~ 10 14 -10 15 GeV. It is still impossible to isolate and test such parts experimentally, because The mass is far away from the energy that is available on the hasty ones like natural structures, and in the flames of the insignificant. When interacting with these vector bosons, neither baryon nor lepton charge is saved. Once again, the number of particles of a new level of elementarity is approaching and has now exceeded a hundred. However, a large number of new particles are required only by theory, rather than by evidence, and, perhaps, other as yet unknown theoretical ones. schemes allow you to get by without many of the already known parts.
Increase in the number of fundamental units Having discussed the theorists' models, which included all families of quarks and leptons, as well as particles - interaction carriers and Higgs bosons, they were seen as warehouses for some more fundamental objects; one of the names that is to be preached for the rest is preoni.
basics The problem facing the theory of preons lies in the fact that the mass of objects m, folded from preons, the fault is small in alignment with the gate size of these objects r-1. U in. On the other hand, with quantum mechanics, the seeming flames may be lost. There is no satisfactory solution to this problem. At the same time, it is absolutely necessary for the structure of matter to guess the “Mother Mother” toy, you cannot turn off the fact that leptons and quarks exist and will once again be deprived of the remaining stage of the crushed speech. The most important word here may lie before the experiment. Unfortunately, experiments on existing accelerators cannot provide evidence of power supply.
4. Elementary parts and cosmology
The primary plasma contained all E. parts, the population of which could be generated at a given plasma temperature. With expanded world temperature T plasma fell, the largest particles stopped growing, which led to the fact that the number of massive stable E.ch. and antiparticles in the so-called elements. the accompanying obligation (in order to expand at the rate of expansion of the Universe) decreased proportionally exp( mc 2 kT). This is the law of change in concentration E.h. having lasted until the present hour (until K), then no traces of E.ch., born in the early stages of the evolution of the whole world, would now be lost. However, if the concentration of such particles becomes low, their mutual annihilation occurs and further concentration of E.H. the expansion of the Metagalaxy falls beyond the limits of expansion (and thus becomes deprived of constant support). This is a sound phenomenon. preserved (or frozen) concentration. For weakly interacting particles, their current concentration is on the order of days. concentration of relic photons 
. This very situation is good for neutrinos. The analysis shows that the number of relic neutrinos may be even greater: (for the skin type of neutrino). The remaining arrangement allows us to eliminate even stronger interference with the neutrino mass: EB. If the mass of all types of neutrinos exceeded the designated limit, then the neutrinos would contribute greatly to the rate of expansion of the Universe and this century, which is calculated per day. the value of the Hubble steady state and the density of the mass of relic neutrinos would have appeared less, but not according to astrophysics. assessments and methods. The proof that the exchange from below to the whole World will lead to the exchange of the beast on the mass of neutrinos was given by S.S. Gershtein and Ya.B. Zeldovich (b. 1966) initiated the stagnation of cosmology. methods to physics E.ch.
Data from cosmology also allow us to conclude that the number of different neutrinos can be quite large (V.F. Shvartsman, 1969). light elements (such as 4 He and deuterium) in the World so that, then. all neutrinos are already closed. True, a number of physicists do not trust the reliability of the original data, and other estimates are reached: . It is possible that sooner or later the number of types of neutrinos will become clear, because vikritii born 1983 The Z 0 boson of weak interactions is to blame, according to the theoretical transfers, decay into all types of neutrinos, and thus the death of their increased intensity of decay is allowed to be significant. Let us explain how the abundance of 4 He and 2 H can be calculated. These elements were created at an early stage of the development of the Universe when the temperature of the primordial plasma became 1 MeV-100 keV (in energy units or 10 10 -10 9 K. At this temperature, the plasma moved at approximately the same level photons, all types of neutrinos, electron-positron pairs and a small number of nucleons (~ 10 -10 per number of light particles) The total volume of neutrons and protons is determined to be thermodynamically equal and becomes , de = 1.3 MeV - p the meaning of the mass of the neutron and proton. e.g., n + p + e - .In the world of expansion, the concentration of particles falls and the fluidity of the reaction of np-transitions becomes less than the fluidity of expansion, the concentration ratio n and p is formed, then the value Nn/Np It becomes steady, as it can benefit from a large decay of neutrons. This value means the absolute displacement (great quantity) of 4 He, because For the sake of the water lancer, almost all neutrons are bound into 4 He nuclei. Obviously, there is a higher rate of expansion and cooling, a higher temperature of hardening and, obviously, a higher rate of deterioration Nn/Np. It can be shown that the greater the number of different types of particles in the primary plasma, the greater the rate of expansion at a given temperature, so the addition of new types of neutrinos to the primary plasma will lead to an increase in the temperature of condensation and, therefore, an increase in concentration tsії primary 4 He. Modern The data indicate that part 4 He (behind the mass) at the edge of the Metagalaxy becomes 22-25%, which is in good agreement with the theory at =3. As if the number of neutrino types became 10-20, the number 4 would not reach 40-50%, which absolutely indicates caution. However, there is a certain insignificance associated with the fact that the significant concentration of nucleons is determined by poor accuracy. For data on the strength of 2 H at Vsesvita, you can also calculate the value f, when it turns on >3. Unfortunately, the relationship between the current quantity of deuterium and the former is meant to be quite poor and does not leave some room for increasing the number.
Cosmology also allows us to work out ideas about particles and processes that are far beyond the energy spectrum. boundaries, accessible knots. and to those who may be in trouble. Let's paint the butt of the yavl. assessment of the concentration of magnetic monopoles - particles that oscillate an elementary magnet. charge. The origin of these particles is transferred to the models of the great unification. Its mass is ~ 10 16 GeV, so there is no hope, either immediately or in the near future, of isolating these particles in the laboratory, just as one would isolate, for example, antiprotons and W- and Z0-bosons.
The only possibility of identifying these particles lies in the search for their middle relic particles. Theoretical The study of the concentration of relict monopolies, based on the simplest model, is important to note with caution. This supernatural reality has become one of the changes for the creation of the formulation of the inflationary model of the World.
Interactions of physics E.ch. That cosmology was especially important in the remaining hours. It's very theoretical. model of interaction E.ch. It cannot be known because it does not comply with the data of cosmology. On the other hand, methods of physics E.ch. allowed us to solve a number of common cosmological problems, such as problems of homogeneity and isotropy, the horizon of the Universe, the closeness of the power of speech to criticality. significant.
1. Elementary parts- These are microobjects whose dimensions do not exceed the dimensions of atomic nuclei. Elementary particles include protons, neutrons, electrons, mesons, neutrinos, photons, etc.
The expression of elementary particles cannot be understood as structureless particles, not created before re-creation. The replacement of any scientific term with the development of science gradually uniques its etymology. Thus, the atom was lost from the manifestations of people until the beginning of the 19th century. In chemical atomism, the currently known scientific atom is a complex dynamic system, subject to various changes. Thus, the elementary particles in the world, under the influence of new authorities, reveal their increasingly complex structure.
The most important thing for the power of elementary particles is their ability to be chewed and mutually transform one into one when connected. To carry out such processes, it is necessary for the particles to stick together with little energy. Therefore, the physics of elementary particles is called the physics of high energies.
Over the course of an hour of life, all elementary particles are divided into three groups: stable, unstable and resonances.
Stable particles can be found in the wild for a long time. There are 11 such particles in total: proton p, e, electron neutrino 0, muon neutrino, thon neutrino, their antiparticles p, e, e, n, . Facts of spontaneous disintegration of these particles have been confirmed.
Do unstable parts loom in the middle hour of life? This is very large in comparison with the characteristic time of nuclear shedding of 10 -23 s (the hour of passage of the light diameter of the nuclei). For example, for a neutron = 16 xv, for a muon = 10 -6 s, for a neutron = 10 -8 s, for hyperons and kaons = 10 -4 s.
Resonances loom in the hours of life, aligned with the passing hour of 10 -23 s. The smells behind the resonances are recorded on the intensity curves of the overcuts of the reaction in the form of energy. A lot of resonances glow as the awakening of nucleons and other particles.
2. Fundamental interactions. The variety of interactions that occur between elementary particles and in nature as a whole can be reduced to 4 main types: strong, electromagnetic, weak and gravitational. Strong interactions suppress nucleons in atomic nuclei and mainly hadrons (protons, neutrons, mesons, hyperons, etc.). Before the electromagnetic, there are interactions that manifest themselves in macroeconomics, viscosity, molecular, chemical, etc. Weak interactions cause β-decay of nuclei and, in conjunction with electromagnetic forces, control the behavior of peptone-elementary particles with a similar spin, so as not to take part in strong interactions. Gravitational interaction is inherent in all material objects.
Maintain fundamental interactions between each other and their intensity. There is no unambiguous understanding of the method of equalizing intensities. Therefore, there will be an equalization of the total number of boxes.
For example, the ratio of the force of gravitational attraction between two protons to the Coulomb force becomes G (m p m p /r 2) /(e 2 /4πε 0 r 2) = 4πε 0 G(m p 2 /e 2) =10 -36. This number is taken as the ratio of gravitational and electromagnetic interaction.
The ratio between strong and electromagnetic interactions, which is determined by the cuts and energies of nuclear reactions, is estimated as 10 4 : 1. In a similar manner, the intensity of strong and weak is equalized and mutuality.
The order of intensity as the world equalizes the interaction of the vicorists at the same time and arises in mutual relations. To equalize the hours, take the speed of processes at kinetic energies of frequency E = 1 GeV. At such energies, processes that interact with strong interactions occur in an hour of nuclear flow 10 -23 s, processes that interact with electromagnetic interactions - in an hour 10 -19 s, weak - in an hour 10 -9 s, gravitational - 10 +16 s .
In some cases, to equalize mutual interaction, take until the end of a long run of particles in the river. Strongly interacting parts with E = 1 GeV are affected by a ball of important metal with a thickness of up to 1 m. Like neutrinos, they can also participate in weak interactions, with an energy 100 times less (E = 10 MeV) balloon 109 km!
A. Mutualism is strong not only the most intense, but the shortest in nature. At elevations that move 10 -15 m, its role becomes insignificant. By ensuring the stability of nuclei, this interaction practically does not affect atomic cells. Strong interaction does not mean universality. This applies not to all particles, but only to hadrons - nucleons, mesons, hyperons, etc.
b. Electromagnetic interaction for intensity, it is sacrificed to the strong by 4 orders of magnitude. The head region of this shows variations ranging from a core diameter of 10 -15 m and up to approximately 1 m. This includes the structure of atoms, molecules, crystals, chemical reactions, deformations, rubbing, light, and other physical objects accessible to the public.
The strongest electromagnetic interaction is with electrically charged particles. Neutral particles with non-zero spin have a weaker effect due to the fact that such particles have a magnetic moment of the order of M=eћ/2m. An even weaker electromagnetic interaction manifests itself in neutral ions π 0 and in neutrinos.
Vinyatkov’s important power of EM-interaction is the evidence of interaction between simultaneously charged particles, as well as gravity between differently charged particles. Therefore, EM interactions between atoms and other objects with zero net charge have a remarkably short radius of action, although the Coulombian forces between charged particles are far-reaching.
e. Weak interaction very little in comparison with strong and electromagnetic. However, due to changes in the environment, it is rapidly growing. If we assume that the dynamics of the increase remain deep, then at distances of approximately 10 -20 m, the weak interaction becomes equal to the strong one. Apart from experimental research, such approaches are not yet available.
Weak interaction sums up the processes of interaction between particles. For example, the sigma - plus - hyperon part, under the influx of weak interaction, breaks down into a proton and a neutral pionium, Σ + => p + π 0 . Due to weak interactions, β-decay occurs. Such parts as hyperons, kaoni, muoni were stable due to weak interactions.
m. Gravitational interaction weakest. It is not characterized by far-reaching, absolute universality (all bodies gravitate) and yet a sign between any pair of particles. The continued power leads to the fact that gravitational forces will always increase due to increased body mass. Therefore, gravity, regardless of all the meager water intensity, assumes a major role in the interactions of cosmic bodies - planets, stars, galaxies
In the light of elementary particles, the role of gravity is insignificant. Therefore, the physics of the atom, the nucleus and the elementary particles of gravitational interaction is not taken into account.
3. Characteristics of elementary particles. Until the beginning of the 50s of the 20th century, while the number of open particles was clearly small, for the description of particles, extraphysical quantities were used - mass m, kinetic energy E, momentum p and one quantum number - spin s, which allowed us to judge the magnitude of mechanical and magnetic moments parts. For unstable particles, the average hour of life was added here.
However, in the regularities of the people and the disintegration of the singing particles, it was possible to see certain signs specific to these particles. For the appointment of these authorities, it was necessary to introduce new quantum numbers. Their actions were called charges.
For example, it was understood that during the decay of important particles, for example, a neutron, it never happens that only particles are created, for example, electrons e - , e + and neutrinos. And finally, with the electrons and positrons closed, it is not possible to remove the neutron, although the laws of conservation of energy and momentum will end. To illustrate this pattern, the quantum number of baryon charge B was introduced. It became important that such important baryon particles have B = 1, and their antiparticles have B = -1. For light particles, B = 0. The result demonstrates the regularity of the formation of the form and the law of conservation of baryon charge.
Similarly, for light particles, quantum numbers were empirically introduced - lepton charges L - signs of the presence of active substances. We understand that lepton charges L e = +1 for electron e - and electron neutrinos ν e,L μ = + 1 for negative muons μ - and muon neutrinos ν μ,L τ = +1 for negative muons τ - and e neutrinos v τ. For primary antiparticles L=-1. Like baryon and leptonic charges, they are conserved in all interactions.
With the discovery of hyperons that occur in strong interactions, it turned out that the current hour of life is not equal to the hour of 10-23 s, which is typical for strongly interacting particles, but 10-13 times longer. This seemed disconcerting and surprising, and can only be explained by the fact that parts that were born in strong relationships fall apart in weak relationships. To reflect such power of particles, a quantum number S was introduced. For unusual particles S = + 1, for their antiparticles S = - 1, for other particles S = 0.
The electric charge Q of microparticles is expressed through its relationship to a positive elementary charge e+. Therefore, the electric charge Q of the particles is also a quantum number. For a proton Q = + 1, for an electron Q = -1, for a neutron, neutrino and other neutral particles Q = 0.
In addition to the names of the parameters, the elementary particles contain other characteristics that are not visible here.
4. Laws of conservation of elementary particles in physics can be divided into three bodies: the external laws of conservation, more precisely the laws of conservation of charges and the nearby laws of conservation.
A . Foreign laws of conservation It is precisely independent of the scale of phenomena - in the micro-, macro- and megaworld. These laws emerge from the geometry of space - time. Uniformity of time leads to the law of conservation of energy, uniformity of space - to the law of conservation of momentum, isotropy of space - to the law of conservation of momentum, equality of ISO - to the law of conservation of the center of inertia. In addition to these 4 laws, this includes two more, related to the symmetry of space - there is often a mirror image of the coordinate axes. From the mirror symmetry of the coordinate axes it follows that the right-left symmetries of space are identical (the law of conservation of pairs). The law related to the mirror symmetry of the hour is to talk about the sameness of phenomena in the microworld by changing the sign of the hour.
b. Precise laws of conservation of charges. Any physical system is assigned a whole charge to the skin type. The skin charge is additive and preserved. There are 5 such charges: electric Q, baryon B, three leagon charges - electron L e, muon L µ ton L τ. All charges are intact and can have either positive or negative values equal to zero.
Electric charge is of even greater significance. Vin is like a quantum number, and y is a force field core. Baryon and leptonic charges are not force field cores. For a folding system, the additional charge of any type is the sum of the different charges of the elementary particles that are included in the system.
V. The laws of conservation are approaching It is difficult to understand certain types of fundamental interactions. The stench reaches such characteristics as divina S and in.
All the listed laws of conservation are summarized in table 26.2.
5. Particles and antiparticles They wash the same mass, but all the charges in them lie down. The vibration from the pair of particles and antiparticles is sufficient. For example, a pair of electron + positron came to regard the electron as a particle, and the positron as an antiparticle. Charge the electron Q = -1, B = 0, Le = +1, L = 0, L = 0. Charge the positron Q = +1, V = 0, Le = -1, L = 0, L =0
All charges of the part + anti-part system reach zero. Such systems, in which all charges reach zero, are called truly neutral. These are truly neutral particles. There are two: γ – quantum (photon) and η – meson. The particles and antiparticles are the same here.
6. Classification of elementary particles not completed yet. This classification is based on the average hour of life, mass m, spin s, five types of charges, divinity S and other parameters of particles. All parts are divided into 4 classes.
1st grade is created by one part - the photon. The photon has zero mass and all charges. Photon is not susceptible to strong interactions. Its spin is equal to 1, so behind the statistics there is a boson.
2nd class to create a lepton. These are light particles with zero baryon charge. In a skin particle - laptop, one of the tape charges is not equal to zero. Leptony is not susceptible to strong interactions. The spin of all leptons is 1/2, so according to the statistics, they smell like fermions.
3rd class create mezzanines. These are particles with zero baryon and lepton charges, which take part in strong interactions. All mesons move a whole spin, just like the statistics of bosons.
4th grade add up baryons. These are important particles with a subzero baryon charge B ≠ Pro and with zero lepton, Le, Lµ, Lτ = 0. They have a full spin (fermions) and take part in strong interactions. Because particles of the 3rd and 4th classes take part in strong interactions, they are also called hadrons.
Table 26. 3 points out the good parts - not resonances with their main characteristics. Particles and antiparticles have been induced. Truly neutral particles, which do not interfere with antiparticles, are located in the middle of the column. Name the parts. It is obvious that the antipart can be obtained simply by adding the prefix “anti” to the name of the Part. For example, proton - antiproton, neutron - antineutron.
The antielectron e + is called a positron, which has developed historically. In relation to charged ponies and kaon, the term “antiparticle” is practically not defined. The stench is eliminated by an electric charge. So it’s easy to talk about positive and negative sounds and kaoni.
The upper sign of the charge is applied to the particle, the lower sign to the antiparticle. For example, for an electron-positron bet Le = ± 1. This means that for an electron Le = + 1, and for a positron Le = -1.
The table has the following meanings: Q - electric charge, baryon charge Le,Lµ,Lτ - apparently, electron, muon, lepton charges, S - divin, s-spin, τ - average hour of life.
The mass is shown in megaelectronvolts. From the relativistic level mc 2 =еU vibrate m=eU/c 2 . The energy of a part of 1 MeV is indicated by the mass m = eU / c 2 = 1.6 * 10 -19 / 9 * 10 16 = 17.71 * 10 -31 kg. There are close to two electronic masses. Dividing the mass of the electron m e = 9.11 * 10 -31 kg, we obtain m = 1.94 m e.
The electron mass, expressed through energy, becomes m e =0.511 MeV.
7. Quark model of hadrons. Hadrons are elementary particles that have strong interactions. These are mesoni and baryons. Born in 1964 Americans Murray Gell-Mann and George Zweig hypothesized that the structure and power of hadrons could be better understood by assuming that hadrons are composed of fundamental particles, which Gell-Mann called quarks. The quark hypothesis turned out to be very clear and immediately accepted.
The number of fortune-telling quarks is steadily increasing. At the time, Nyabilsh is good Vivcheni 5 riznovidiv (aroma) quarka: quarc u z Masoya m u = 5 mate, quark d zoma m D = 7 mevas, quark s ms = 150 meals, quark s z ts = 1300 meva kwa mb = 5000 MeV. The same quark has its own antiquark.
All the above quarks have a new spin of 1/2 and a new baryon charge B = 1/3. Quarks u, c carry a fractional positive charge Q = + 2/3, quarks d, s, b carry
shotgun negative charge Q = – 1/3. Quark s is a beauty, a quark is a quark, a quark is a beauty (Table 26.4).
A hadron can be thought of as a combination of many quarks. Quantum numbers Q, B, S of hadrons come out as the sum of the corresponding numbers of storage hadrons of quarks. If two quarks enter a hadron, then their backs are parallel.
Baryons have a completely different spin, so they can be composed of an unpaired number of quarks. For example, a proton is made up of three quarks, p => uud. Electric charge on a proton Q =+ 2/3+2/3 – 1/3 = 1, baryon charge on a proton B = 1/3+ 1/3 + 1/3 = 1, divin S = O, spin s = 1/2 - 1/2 +1/2 = 1/2.
A neutron is also made up of three quarks, n => udd. Q = 2/3-1/3-1/3 = O, B = 1/3+1/3+1/3=1, S = 0, s = 1/2 - 1/2 + 1/2 = 1/2. A combination of three quarks can represent the following baryons: Λ 0 (uds), Σ + (uus), Σ 0 (uds), Σ - (dds), Ξ 0 (uss), Ξ - (dss), Ω - (sss) a ° (uss). In the remaining case, the backs of all quarks are straightened into one bend. Therefore - - the hyperon has a spin of 3/2.
Antiparticles of baryons are created from similar antiquarks.
Mesons are composed of two quarks and antiquarks. For example, positive pivonia π + (ud). Yogo charge Q = +2/3- (-1/3) = 1, B = 1/3-1/3 = O, S = 0, spin 1/2 - 1/2 = 0.
The quark model conveys that quarks exist in the middle of hadrons, and evidence shows that they cannot fly out from hadrons. Let’s take advantage of those energies that can be reached in today’s haste. It is very certain that the quarks have burned out and cannot sleep in the wild.
Modern high-energy physics takes into account that the interaction between quarks occurs in the form of special particles - gluons. The quiet mass of gluons is equal to zero, the spin is equal to unity. The creation of nearly a dozen different types of gluons is allowed.