ELEMENTARY PARTICLES- primary, further indecomposable particles, of which all matter is believed to consist. In modern physics, the term "elementary particles" is usually used to designate a large group of tiny particles of matter that are not atoms (see Atom) or atomic nuclei (see Atomic nucleus); The exception is the nucleus of the hydrogen atom - the proton.
By the 80s of the 20th century, science knew more than 500 elementary particles, most of which were unstable. Elementary particles include proton (p), neutron (n), electron (e), photon (γ), pi-mesons (π), muons (μ), heavy leptons (τ +, τ -), neutrinos of three types - electronic (V e), muonic (V μ) and associated with the so-called heavy depton (V τ), as well as “strange” particles (K-mesons and hyperons), various resonances, mesons with hidden charm, “charmed” particles, upsilon particles (Υ), “beautiful” particles, intermediate vector bosons, etc. An independent branch of physics has emerged - the physics of elementary particles.
The history of particle physics dates back to 1897, when J. J. Thomson discovered the electron (see Electron radiation); in 1911, R. Millikan measured the magnitude of its electric charge. The concept of “photon” - quantum of light - was introduced by M. Planck in 1900. Direct experimental evidence of the existence of the photon was obtained by Millikan (1912-1915) and Compton (A. N. Compton, 1922). In the process of studying the atomic nucleus, E. Rutherford discovered the proton (see Proton radiation), and in 1932, J. Chadwick discovered the neutron (see Neutron radiation). In 1953, the existence of neutrinos, which W. Pauli had predicted back in 1930, was experimentally proven.
Elementary particles are divided into three groups. The first is represented by a single elementary particle - a photon, γ-quantum, or quantum of electromagnetic radiation. The second group is leptons (Greek leptos small, light), participating, in addition to electromagnetic ones, also in weak interactions. There are 6 known leptons: electron and electron neutrino, muon and muon neutrino, heavy τ-lepton and the corresponding neutrino. The third - main group of elementary particles are hadrons (Greek hadros large, strong), which participate in all types of interactions, including strong interactions (see below). Hadrons include particles of two types: baryons (Greek barys heavy) - particles with half-integer spin and a mass no less than the mass of a proton, and mesons (Greek mesos medium) - particles with zero or integer spin (see Electron paramagnetic resonance). Baryons include the proton and neutron, hyperons, some resonances and “charmed” particles and some other elementary particles. The only stable baryon is the proton, the rest of the baryons are unstable (a neutron in a free state is an unstable particle, but in a bound state inside stable atomic nuclei it is stable. Mesons got their name because the masses of the first discovered mesons - the pi-meson and the K-meson - had values intermediate between the masses of a proton and an electron. Later, mesons were discovered whose mass exceeds the mass of a proton. Hadrons are also characterized by strangeness (S) - zero, positive or negative quantum number. Hadrons with zero strangeness are called ordinary, and with S ≠ 0 - strange. In 1964, G. Zweig and M. Gell-Mann independently suggested the quark structure of hadrons. The results of a number of experiments indicate that quarks are real material formations inside quarks. have a number of unusual properties, for example, fractional electric charge, etc. Quarks have not been observed in a free state. It is believed that all hadrons are formed due to various combinations of quarks.
Initially, elementary particles were studied in the study of radioactive decay (see Radioactivity) and cosmic radiation (see). However, since the 50s of the 20th century, studies of elementary particles have been carried out on charged particle accelerators (see), in which accelerated particles bombard a target or collide with particles flying towards them. In this case, the particles interact with each other, resulting in their interconversion. This is how most elementary particles were discovered.
Each elementary particle, along with the specifics of its inherent interactions, is described by a set of discrete values of certain physical quantities, expressed in integer or fractional numbers (quantum numbers). The common characteristics of all elementary particles are mass (m), lifetime (t), spin (J) - the intrinsic angular momentum of elementary particles, which has a quantum nature and is not associated with the movement of the particle as a whole, electric charge (Ω) and magnetic moment ( μ). The electric charges of the studied elementary particles in absolute value are integer multiples of the electron charge (e≈1.6*10 -10 k). Known elementary particles have electric charges equal to 0, ±1 and ±2.
All elementary particles have corresponding antiparticles, the mass and spin of which are equal to the mass and spin of the particle, and the electric charge, magnetic moment and other characteristics are equal in absolute value and opposite in sign. For example, the antiparticle of an electron is a positron - an electron with a positive electrical charge. An elementary particle that is identical to its antiparticle is called truly neutral, for example, a neutron and an antineutron, a neutrino and an antineutrino, etc. When antiparticles interact with each other, their annihilation occurs (see).
When an elementary particle enters a material environment, it interacts with it. There are strong, electromagnetic, weak and gravitational interactions. Strong interaction (stronger than electromagnetic interaction) occurs between elementary particles located at a distance of less than 10 -15 m (1 Fermi). At distances greater than 1.5 Fermi, the interaction force between particles is close to zero. It is the strong interactions between elementary particles that provide the exceptional strength of atomic nuclei, which underlies the stability of matter under terrestrial conditions. A characteristic feature of the strong interaction is its independence of electric charge. Hadrons are capable of strong interactions. Strong interactions cause the decay of short-lived particles (lifetime of the order of 10 -23 - 10 -24 sec.), which are called resonances.
All charged elementary particles, photons and neutral particles with a magnetic moment (for example, neutrons) are subject to electromagnetic interaction. The basis of electromagnetic interactions is the connection with the electromagnetic field. The forces of electromagnetic interaction are approximately 100 times weaker than the forces of strong interaction. The main scope of electromagnetic interaction is atoms and molecules (see Molecule). This interaction determines the structure of solids and the nature of the chemical. processes. It is not limited by the distance between elementary particles, so the size of an atom is approximately 10 4 times the size of the atomic nucleus.
Weak interactions underlie extremely slow processes involving elementary particles. For example, neutrinos, which have a weak interaction, can easily penetrate the thickness of the Earth and the Sun. Weak interactions also cause slow decays of so-called quasi-stable elementary particles, the lifetime of which is in the range of 10 8 - 10 -10 sec. Elementary particles born during strong interaction (in a time of 10 -23 -10 -24 sec.), but decaying slowly (10 -10 sec.), are called strange.
Gravitational interactions between elementary particles produce extremely small effects due to the insignificance of the particle masses. This type of interaction has been well studied on macro-objects with large masses.
The diversity of elementary particles with different physical characteristics explains the difficulty of their systematization. Of all the elementary particles, only photons, electrons, neutrinos, protons and their antiparticles are actually stable, since they have a long lifetime. These particles are the end products of the spontaneous transformation of other elementary particles. The birth of elementary particles can occur as a result of the first three types of interactions. For strongly interacting particles, the source of creation is strong interaction reactions. Leptons, most likely, arise from the decay of other elementary particles or are born in pairs (particle + antiparticle) under the influence of photons.
Flows of elementary particles form ionizing radiation (see), causing ionization of neutral molecules of the medium. The biological effect of elementary particles is associated with the formation of substances with high chemical activity in irradiated tissues and body fluids. These substances include free radicals (see Free radicals), peroxides (see) and others. Elementary particles can also have a direct effect on biomolecules and supramolecular structures, cause the rupture of intramolecular bonds, depolymerization of high-molecular compounds, etc. The processes of energy migration and the formation of metastable compounds resulting from long-term preservation of the state of excitation in some macromolecular substrates. In cells, the activity of enzyme systems is suppressed or distorted, the structure of cell membranes and surface cell receptors changes, which leads to an increase in membrane permeability and a change in diffusion processes, accompanied by the phenomena of protein denaturation, tissue dehydration, and disruption of the internal environment of the cell. The susceptibility of cells largely depends on the intensity of their mitotic division (see Mitosis) and metabolism: with an increase in this intensity, the radiosusceptibility of tissues increases (see Radiosensitivity). Their use for radiation therapy (see), especially in the treatment of malignant neoplasms, is based on this property of flows of elementary particles - ionizing radiation. The penetrating ability of charged elementary particles depends to a large extent on the linear transfer of energy (see), that is, on the average energy absorbed by the medium at the point of passage of the charged particle, per unit of its path.
The damaging effect of the flow of elementary particles especially affects the stem cells of hematopoietic tissue, epithelium of the testicles, small intestine, and skin (see Radiation sickness, Radiation damage). First of all, systems that are in a state of active organogenesis and differentiation during irradiation are affected (see Critical organ).
The biological and therapeutic effect of elementary particles depends on their type and dose of radiation (see Doses of ionizing radiation). For example, when exposed to X-ray radiation (see X-ray therapy), gamma radiation (see Gamma therapy) and proton radiation (see Proton therapy) on the entire human body at a dose of about 100 rad, a temporary change in hematopoiesis is observed; external influence of neutron radiation (see Neutron radiation) leads to the formation in the body of various radioactive substances, for example, radionuclides of sodium, phosphorus, etc. When radionuclides that are sources of beta particles (electrons or positrons) or gamma quanta enter the body, this happens called internal irradiation of the body (see Incorporation of radioactive substances). Especially dangerous in this regard are rapidly resorbing radionuclides with a uniform distribution in the body, for example. tritium (3H) and polonium-210.
Radionuclides, which are sources of elementary particles and participate in metabolism, are used in radioisotope diagnostics (see).
Bibliography: Akhiezer A.I. and Rekalo M.P. Biography of elementary particles, Kyiv, 1983, bibliogr.; Bogolyubov N. N. and Shirokov D. V. Quantum fields, M., 1980; Born M. Atomic physics, trans. from English, M., 1965; Jones X. Physics of Radiology, trans. from English. M., 1965; Krongauz A. N., Lyapidevsky V. K. and Frolova A. V. Physical foundations of clinical dosimetry, M., 1969; Radiation therapy using high-energy radiation, ed. I. Becker and G. Schubert, trans. from German, M., 1964; Tyubiana M. et al. Physical foundations of radiation therapy and radiobiology, trans. from French, M., 1969; Shpolsky E.V. Atomic physics, vol. 1, M., 1984; Young Ch. Elementary particles, trans. from English. M., 1963.
R. V. Stavntsky.
In which there is information that all the elementary particles that make up any chemical element consist of a different number of indivisible phantom Po particles, I became interested in why the report does not talk about quarks, since it is traditionally believed that they are structural elements of elementary particles.
The theory of quarks has long become generally accepted among scientists who study the microworld of elementary particles. And although at the very beginning the introduction of the concept of “quark” was a purely theoretical assumption, the existence of which was only supposedly confirmed experimentally, today this concept is operated as an inexorable truth. The scientific world has agreed to call quarks fundamental particles, and over several decades this concept has become the central theme of theoretical and experimental research in the field of high-energy physics. “Quark” was included in the curriculum of all natural science universities in the world. Enormous funds are allocated for research in this area - just what does it cost to build the Large Hadron Collider. New generations of scientists, studying the theory of quarks, perceive it in the form in which it is presented in textbooks, with virtually no interest in the history of this issue. But let's try to unbiasedly and honestly look at the root of the “quark question”.
By the second half of the 20th century, thanks to the development of the technical capabilities of elementary particle accelerators - linear and circular cyclotrons, and then synchrotrons, scientists were able to discover many new particles. However, they did not understand what to do with these discoveries. Then the idea was put forward, based on theoretical considerations, to try to group particles in search of a certain order (similar to the periodic system of chemical elements - the periodic table). Scientists agreed name heavy and medium-mass particles hadrons, and further divide them into baryons And mesons. All hadrons participated in the strong interaction. Less heavy particles are called leptons, they participated in electromagnetic and weak interactions. Since then, physicists have tried to explain the nature of all these particles, trying to find a common model for all that describes their behavior.
In 1964, American physicists Murray Gell-Mann (Nobel Prize winner in physics 1969) and George Zweig independently proposed a new approach. A purely hypothetical assumption was put forward that all hadrons consist of three smaller particles and their corresponding antiparticles. And Gell-Man named these new particles quarks. It’s interesting that he borrowed the name itself from James Joyce’s novel “Finnegan’s Wake,” where the hero often heard words about the mysterious three quarks in his dreams. Either Gell-Man was too emotional about this novel, or he simply liked the number three, but in his scientific works he proposes to introduce the first three quarks, called the top quark, into elementary particle physics. (And - from English up), lower (d— down) and strange (s- strange), having a fractional electric charge of + 2/3, - 1/3 and - 1/3, respectively, and for antiquarks, assume that their charges are opposite in sign.
According to this model, protons and neutrons, which scientists assume make up all the nuclei of chemical elements, are composed of three quarks: uud and udd, respectively (those ubiquitous three quarks again). Why exactly out of three and in that order was not explained. It’s just something that authoritative scientific men came up with and that’s it. Attempts to make a theory beautiful do not bring us closer to the Truth, but only distort the already distorted mirror in which a piece of It is reflected. By complicating the simple, we move away from the Truth. And it's so simple!
This is how “high-precision” generally accepted official physics is built. And although the introduction of quarks was initially proposed as a working hypothesis, after a short time this abstraction became firmly established in theoretical physics. On the one hand, it made it possible from a mathematical point of view to solve the issue of ordering a vast series of open particles, on the other hand, it remained only a theory on paper. As is usually done in our consumer society, a lot of human effort and resources were directed toward experimental testing of the hypothesis of the existence of quarks. Taxpayer funds are spent, people need to be told about something, show reports, talk about their “great” discoveries in order to receive another grant. “Well, if it’s necessary, then we’ll do it,” they say in such cases. And then it happened.
A team of researchers from the Stanford Department of the Massachusetts Institute of Technology (USA) used a linear accelerator to study the nucleus, firing electrons at hydrogen and deuterium (a heavy isotope of hydrogen, the nucleus of which contains one proton and one neutron). In this case, the angle and energy of electron scattering after the collision were measured. In the case of low electron energies, the scattered protons with neutrons behaved like “homogeneous” particles, slightly deflecting the electrons. But in the case of high-energy electron beams, individual electrons lost a significant part of their initial energy, scattering at large angles. American physicists Richard Feynman (Nobel Prize winner in physics 1965 and, incidentally, one of the creators of the atomic bomb in 1943-1945 at Los Alamos) and James Bjorken interpreted electron scattering data as evidence of the composite structure of protons and neutrons, namely : in the form of previously predicted quarks.
Please pay attention to this key point. Experimenters in accelerators, colliding beams of particles (not single particles, but beams!!!), collecting statistics (!!!) saw that the proton and neutron consist of something. But from what? They didn’t see quarks, and even in the number of three, this is impossible, they just saw the distribution of energies and the scattering angles of the particle beam. And since the only theory of the structure of elementary particles at that time, albeit a very fantastic one, was the theory of quarks, this experiment was considered the first successful test of the existence of quarks.
Later, of course, other experiments and new theoretical justifications followed, but their essence is the same. Any schoolchild, having read the history of these discoveries, will understand how far-fetched everything in this area of physics is, how simply dishonest everything is.
This is how experimental research is carried out in the field of science with a beautiful name - high energy physics. Let's be honest with ourselves, today there is no clear scientific justification for the existence of quarks. These particles simply do not exist in nature. Does any specialist understand what actually happens when two beams of charged particles collide in accelerators? The fact that the so-called Standard Model, which is supposedly the most accurate and correct, was built on this quark theory does not mean anything. Experts are well aware of all the flaws of this latest theory. But for some reason it is customary to remain silent about this. But why? “And the biggest criticism of the Standard Model concerns gravity and the origin of mass. The standard model does not take gravity into account and requires that the mass, charge and some other properties of particles be measured experimentally for subsequent inclusion in equations."
Despite this, huge amounts of money are allocated to this area of research, just think about it, to confirm the Standard Model, and not to search for the Truth. The Large Hadron Collider (CERN, Switzerland) and hundreds of other accelerators around the world have been built, awards and grants are given out, a huge staff of technical specialists is maintained, but the essence of all this is a banal deception, Hollywood and nothing more. Ask any person what real benefit this research brings to society - no one will answer you, since this is a dead-end branch of science. Since 2012, there has been talk about the discovery of the Higgs boson at the accelerator at CERN. The history of these studies is a whole detective story, based on the same deception of the world community. It is interesting that this boson was allegedly discovered precisely after there was talk of stopping funding for this expensive project. And in order to show society the importance of these studies, to justify their activities, in order to receive new tranches for the construction of even more powerful complexes, CERN employees working in these studies had to make a deal with their conscience, wishful thinking.
The report “PRIMODIUM ALLATRA PHYSICS” contains the following interesting information on this subject: “Scientists have discovered a particle supposedly similar to the Higgs boson (the boson was predicted by the English physicist Peter Higgs (1929), according to the theory , it must have finite mass and no spin). In fact, what scientists discovered is not the sought-after Higgs boson. But these people, without even realizing it, made a really important discovery and discovered much more. They experimentally discovered a phenomenon that is described in detail in the AllatRa book. (note: AllatRa book, page 36, last paragraph). .
How does the microcosm of matter actually work? The report “PRIMODIUM ALLATRA PHYSICS” contains reliable information about the true structure of elementary particles, knowledge that was known to ancient civilizations, for which there is irrefutable evidence in the form of artifacts. Elementary particles consist of different numbers phantom Poe particles. “A phantom Po particle is a clot consisting of septons, around which there is a small rarefied septonic field of its own. The phantom Po particle has an internal potential (it is its carrier), which is renewed in the process of ezoosmosis. According to the internal potential, the phantom Po particle has its own proportionality. The smallest phantom Po particle is the unique power phantom particle Po - Allat (note: for more details, see later in the report). A phantom Po particle is an ordered structure in constant spiral motion. It can only exist in a bound state with other phantom Po particles, which in a conglomerate form the primary manifestations of matter. Due to its unique functions, it is a kind of phantom (ghost) for the material world. Considering that all matter consists of phantom Po particles, this gives it the characteristic of an illusory structure and a form of being dependent on the process of ezoosmosis (filling of internal potential).
Phantom Poe particles are an intangible formation. However, in concatenation (serial connection) with each other, built according to the information program in a certain quantity and order, at a certain distance from each other, they form the basis of the structure of any matter, determine its diversity and properties, thanks to their internal potential (energy and information). A phantom Po particle is what elementary particles (photon, electron, neutrino, etc.) are basically made of, as well as particles that carry interactions. This is the primary manifestation of matter in this world."
After reading this report, having conducted such a small study of the history of the development of the theory of quarks and high-energy physics in general, it became clear how little a person knows if he limits his knowledge only to the framework of a materialistic worldview. Some crazy assumptions, probability theory, conditional statistics, agreements and lack of reliable knowledge. But people sometimes spend their lives on this research. I am sure that among scientists and this field of physics there are many people who really came to science not for the sake of fame, power and money, but for the sake of one goal - knowledge of the Truth. When the knowledge of the “PRIMODIUM ALLATRA PHYSICS” becomes available to them, they themselves will restore order and make truly epoch-making scientific discoveries that will bring real benefits to society. With the publication of this unique report, a new page in world science has opened today. Now the question is not about knowledge as such, but about whether people themselves are ready for the creative use of this Knowledge. It is within the power of every person to do everything possible so that we all overcome the consumer format of thinking imposed on us and come to understand the need to create the foundations for building a spiritually creative society of the future in the coming era of global cataclysms on planet Earth.
Valery Vershigora
Keywords: quarks, quark theory, elementary particles, Higgs boson, PRIMORDIAL ALLATRA PHYSICS, Large Hadron Collider, future science, phantom Po particle, septon field, allat, knowledge of truth.
Literature:
Kokkedee Y., Theory of quarks, M., Publishing House "Mir", 340 pp., 1969, http://nuclphys.sinp.msu.ru/books/b/Kokkedee.htm;
Arthur W. Wiggins, Charles M. Wynn, The Five Biggest Unsolved Problems in Science, John Wiley & Sons, Inc., 2003 // Wiggins A., Wynn C. “Five Unsolved Problems of Science” in trans. into Russian;
Observation of an Excess of Events in the Search for the Standard Model Higgs boson with the ATLAS detector at the LHC, 09 Jul 2012, CERN LHC, ATLAS, http://cds.cern.ch/record/1460439 ;
Observation of a new boson with a mass near 125 GeV, 9 Jul 2012, CERN LHC, CMS, http://cds.cern.ch/record/1460438?ln=en ;
Report “PRIMODIUM ALLATRA PHYSICS” by an international group of scientists of the International Social Movement “ALLATRA”, ed. Anastasia Novykh, 2015;
ELEMENTARY PARTICLES, in a narrow sense, are particles that cannot be considered to consist of other particles. In modern In physics, the term “elementary particles” is used in a broader sense: the so-called. the smallest particles of matter, subject to the condition that they are not and (the exception is); Sometimes for this reason elementary particles are called subnuclear particles. Most of these particles (more than 350 of them are known) are composite systems.
E elementary particles participate in electromagnetic, weak, strong and gravitational interactions. Due to the small masses of elementary particles, their gravitational interaction. usually not taken into account. All elementary particles are divided into three main ones. groups. The first consists of the so-called. Bosons are carriers of the electroweak interaction. This includes a photon, or a quantum of electromagnetic radiation. The rest mass of a photon is zero, therefore the speed of propagation of electromagnetic waves (including light waves) represents the maximum speed of propagation of physical. impact and is one of the funds. physical permanent; it is accepted that c = (299792458 1.2) m/s.
The second group of elementary particles are leptons, participating in electromagnetic and weak interactions. There are 6 known leptons: , electron, muon, heavy-lepton and the corresponding one. (symbol e) is considered to be the material of the smallest mass in nature m c, equal to 9.1 x 10 -28 g (in energy units 0.511 MeV) and the smallest negative. electric charge e = 1.6 x 10 -19 C. (symbol) - particles with a mass of approx. 207 mass (105.7 MeV) and electric. charge equal to the charge ; A heavy lepton has a mass of approx. 1.8 GeV. The three types corresponding to these particles are electron (symbol v c), muon (symbol) and neutrino (symbol) - light (possibly massless) electrically neutral particles.
All leptons have (-), i.e., statistically. St. you are fermions (see).
Each of the leptons corresponds to , which has the same mass values and other characteristics, but differs in electrical sign. charge. There are (symbol e +) - in relation to, positively charged (symbol) and three types of antineutrinos (symbol), which are attributed to the opposite sign of a special quantum number, called. lepton charge (see below).
The third group of elementary particles are hadrons, they participate in strong, weak and electromagnetic interactions. Hadrons are “heavy” particles with a mass significantly greater than that of . This is the most a large group of elementary particles. Hadrons are divided into baryons - particles with mesons - particles with an integer (O or 1); as well as the so-called resonances are short-lived hadrons. Baryons include (symbol p) - a nucleus with a mass ~ 1836 times greater than m s and equal to 1.672648 x 10 -24 g (938.3 MeV), and put. electric charge equal to the charge, and also (symbol n) - an electrically neutral particle, the mass of which slightly exceeds the mass. From and everything is built, namely a strong interaction. determines the connection of these particles with each other. In strong interaction and have the same properties and are considered as two of one particle - nucleons with isotopic. (see below). Baryons also include hyperons - elementary particles with a mass greater than the nucleon: a hyperon has a mass of 1116 MeV, a hyperon has a mass of 1190 MeV, a hyperon has a mass of 1320 MeV, and a hyperon has a mass of 1670 MeV. Mesons have masses intermediate between the masses and (-meson, K-meson). There are neutral and charged mesons (with positive and negative elementary electric charge). All mesons have their own characteristics. St. you belong to bosons.
Basic properties of elementary particles. Each elementary particle is described by a set of discrete physical values. quantities (quantum numbers). General characteristics of all elementary particles - mass, lifetime, electricity. charge.
Depending on their lifetime, elementary particles are divided into stable, quasi-stable and unstable (resonances). Stable (within the accuracy of modern measurements) are: (lifetime more than 5 -10 21 years), (more than 10 31 years), photon and . Quasi-stable particles include particles that decay due to electromagnetic and weak interactions; their lifetimes are more than 10–20 s. Resonances decay due to strong interactions, their characteristic lifetimes are 10 -22 -10 -24 s.
The internal characteristics (quantum numbers) of elementary particles are lepton (symbol L) and baryon (symbol B) charges; these numbers are considered to be strictly conserved quantities for all types of funds. interaction For leptonics and their L have opposite signs; for baryons B = 1, for the corresponding ones B = -1.
Hadrons are characterized by the presence of special quantum numbers: “strangeness”, “charm”, “beauty”. Ordinary (non-strange) hadrons are ,-mesons. Within different groups of hadrons there are families of particles that are similar in mass and with similar properties with respect to the strong interaction, but with different characteristics. electrical values charge; the simplest example is the proton and . The total quantum number for such elementary particles is the so-called. isotopic , which, like regular , accepts integer and half-integer values. The special characteristics of hadrons also include internal parity, which takes values 1.
An important property of elementary particles is their ability to undergo mutual transformations as a result of electromagnetic or other interactions. One of the types of mutual transformations is the so-called. birth, or formation at the same time of a particle and (in the general case - the formation of elementary particles with opposite leptonic or baryon charges). Possible processes include the birth of electron-positron e - e + , muon new heavy particles in collisions of leptons, and the formation of cc- and bb-states from quarks (see below). Another type of interconversion of elementary particles is annihilation during particle collisions with the formation of a finite number of photons (quanta). Typically, 2 photons are produced when the total of colliding particles is zero and 3 photons are produced when the total is equal to 1 (a manifestation of the law of conservation of charge parity).
Under certain conditions, in particular at a low speed of colliding particles, the formation of a coupled system - e - e + and These unstable systems are often called. , their lifetime in the substance largely depends on the properties of the substance, which makes it possible to use condenser to study the structure. substances and kinetics of fast chemicals. districts (see,).
Quark model of hadrons. A detailed examination of the quantum numbers of hadrons with a view to them allowed us to conclude that strange hadrons and ordinary hadrons together form associations of particles with close properties, called unitary multiplets. The numbers of particles included in them are 8 (octet) and 10 (decuplet). The particles that are part of a unitary multiplet have the same internal parity, but differ in electrical values. charge (particles of the isotopic multiplet) and strangeness. The properties associated with unitary groups, their discovery was the basis for the conclusion about the existence of special structural units from which hadrons and quarks are constructed. It is believed that hadrons are combinations of 3 fundamentals. particles with 1/2: up-quarks, d-quarks and s-quarks. Thus, mesons are made up of a quark and an antiquark, baryons are made up of 3 quarks.
The assumption that hadrons are composed of 3 quarks was made in 1964 (J. Zweig and, independently, M. Gell-Mann). Subsequently, two more quarks were included in the model of the structure of hadrons (in particular, in order to avoid contradictions with ) - “charmed” (c) and “beautiful” (b), and also special characteristics of quarks were introduced - “flavor” and “ color". Quarks, acting as components of hadrons, have not been observed in a free state. All the diversity of hadrons is due to different factors. combinations of and-, d-, s-, c- and b-quarks forming connected states. Ordinary hadrons ( , -mesons) correspond to connected states built from up- and d-quarks. The presence in a hadron, along with up and d quarks, of one s-, c- or b-quark means that the corresponding hadron is “strange”, “charmed” or “beautiful”.
The quark model of the structure of hadrons was confirmed as a result of experiments carried out at the end. 60s - early
70s 20th century Quarks actually began to be considered as new elementary particles - truly elementary particles for the hadronic form of matter. The unobservability of free quarks, apparently, is of a fundamental nature and suggests that they are those elementary particles that close the chain of structural components of the body. There are theoretical and experiment. arguments in favor of the fact that the forces acting between quarks do not weaken with distance, i.e., to separate quarks from each other an infinitely large amount of energy is required or, in other words, the emergence of quarks in a free state is impossible. This makes them a completely new type of structural units in the island. It is possible that quarks act as the last stage of matter.
Brief historical information. The first elementary particle discovered was - neg. electric charge in both electrical signs. charge (K. Anderson and S. Neddermeyer, 1936), and K-mesons (S. Powell's group, 1947; the existence of such particles was suggested by H. Yukawa in 1935). In the end 40s - early 50s "strange" particles were discovered. The first particles of this group - K + - and K - -mesons, A-hyperons - were also recorded in space. rays
From the beginning 50s accelerators have become the main elementary particle research tool. The antiproton (1955), antineutron (1956), anti-hyperon (1960), and in 1964 the heaviest one were discovered W -hyperon. In the 1960s A large number of extremely unstable resonances were discovered at accelerators. In 1962 it turned out that there are two different ones: electron and muon. In 1974, massive (3-4 proton masses) and at the same time relatively stable (compared to ordinary resonances) particles were discovered, which turned out to be closely related to a new family of elementary particles - “charmed”, their first representatives were discovered in 1976 In 1975, a heavy analogue of the lepton was discovered, in 1977 - particles with a mass of about ten proton masses, in 1981 - “beautiful” particles. In 1983, the heaviest known elementary particles were discovered - bosons (mass 80 GeV) and Z° (91 GeV).
Thus, over the years since the discovery, a huge number of different microparticles have been identified. The world of elementary particles turned out to be complex, and their properties were unexpected in many respects.
Lit.: Kokkede Ya., Theory of quarks, [trans. from English], M., 1971; Markov M. A., On the nature of matter, M., 1976; Okun L.B., Leptons and quarks, 2nd ed., M., 1990.
The physics of elementary particles is closely related to the physics of the atomic nucleus. This area of modern science is based on quantum concepts and in its development penetrates further into the depths of matter, revealing the mysterious world of its fundamental principles. In elementary particle physics, the role of theory is extremely important. Due to the impossibility of direct observation of such material objects, their images are associated with mathematical equations, with prohibiting and allowing rules imposed on them.
By definition, elementary particles are the primary, indecomposable formations from which, by assumption, all matter consists. In fact, this term is used in a broader sense - to designate a large group of microparticles of matter that are not structurally united into nuclei and atoms. Most objects of study in particle physics do not meet the strict definition of elementarity, since they are composite systems. Therefore, particles that satisfy this requirement are usually called truly elementary.
The first elementary particle discovered in the process of studying the microcosm back at the end of the 19th century was the electron. The proton was discovered next (1919), followed by the neutron, discovered in 1932. The existence of the positron was theoretically predicted by P. Dirac in 1931, and in 1932 this positively charged “twin” of the electron was discovered in cosmic rays by Carl Anderson . The assumption of the existence of neutrinos in nature was put forward by W. Pauli in 1930, and it was discovered experimentally only in 1953. In the composition of cosmic rays in 1936, mu-mesons (muons) were found - particles of both signs of electric charge with mass about 200 electron masses. In all other respects, the properties of muons are very close to the properties of the electron and positron. Also in cosmic rays, positive and negative pi mesons were discovered in 1947, the existence of which was predicted by the Japanese physicist Hideki Yukawa in 1935. It later turned out that a neutral pi meson also exists.
In the early 50s. a large group of particles with very unusual properties was discovered, which prompted them to be called “strange”. The first particles of this group were discovered in cosmic rays, these are K-mesons of both signs and a K-hyperon (lambda hyperon). Note that mesons got their name from the Greek. “average, intermediate” due to the fact that the masses of the first discovered particles of this type (pi-mesons, mu-mesons) have a mass intermediate between the mass of a nucleon and an electron. Hyperons take their name from the Greek. “above, higher”, since their masses exceed the mass of a nucleon. Subsequent discoveries of strange particles were made using charged particle accelerators, which became the main tool for studying elementary particles.
This is how the antiproton, antineutron and a number of hyperons were discovered. In the 60s A significant number of particles with an extremely short lifetime were discovered, which were called resonances. As it turned out, most of the known elementary particles belong to resonances. In the mid-70s. a new family of elementary particles was discovered, which received the romantic name “charmed”, and in the early 80s - a family of “beautiful” particles and the so-called intermediate vector bosons. The discovery of these particles was a brilliant confirmation of the theory based on the quark model of elementary particles, which predicted the existence of new particles long before they were discovered.
Thus, during the time after the discovery of the first elementary particle - the electron - many (about 400) microparticles of matter were discovered in nature, and the process of discovery of new particles continues. It turned out that the world of elementary particles is very, very complex, and their properties are varied and often extremely unexpected.
All elementary particles are material formations of extremely small masses and sizes. Most of them have masses on the order of the mass of a proton (~10 -24 g) and dimensions of the order of 10 -13 m. This determines the purely quantum specificity of their behavior. An important quantum property of all elementary particles (including the photon that belongs to them) is that all processes with them occur in the form of a sequence of acts of emission and absorption (the ability to be born and destroyed when interacting with other particles). Processes involving elementary particles relate to all four types of fundamental interactions, strong, electromagnetic, weak and gravitational. The strong interaction is responsible for the bonding of nucleons in the atomic nucleus. Electromagnetic interaction ensures the connection of electrons with nuclei in an atom, as well as the connection of atoms in molecules. Weak interaction causes, in particular, the decay of quasi-stable (i.e., relatively long-lived) particles with a lifetime within 10 -12 -10 -14 s. Gravitational interaction at distances characteristic of elementary particles of ~10 -13 cm, due to the smallness of their mass, has extremely low intensity, but can be significant at ultra-short distances. The intensities of interactions, strong, electromagnetic, weak and gravitational - at moderate energy of the processes are respectively 1, 10 -2, 10 -10, 10 -38. In general, as the particle energy increases, this ratio changes.
Elementary particles are classified according to various criteria, and it must be said that in general their accepted classification is quite complex.
Depending on their participation in various types of interactions, all known particles are divided into two main groups: hadrons and leptons.
Hadrons participate in all types of interactions, including strong ones. They got their name from the Greek. "big, strong."
Leptons do not participate in the strong interaction. Their name comes from the Greek. “light, thin”, since the masses were known until the mid-70s. particles of this class were noticeably smaller than the masses of all other particles (except for the photon).
Hadrons include all baryons (a group of particles with a mass not less than the mass of a proton, so named from the Greek “heavy”) and mesons. The lightest baryon is the proton.
Leptons are, in particular, the electron and positron, muons of both signs, neutrinos of three types (light, electrically neutral particles participating only in weak and gravitational interactions). It is assumed that neutrinos are as common in nature as photons, and many different processes lead to their formation. A distinctive feature of the neutrino is its enormous penetrating power, especially at low energies. Completing the classification by types of interaction, it should be noted that the photon takes part only in electromagnetic and gravitational interactions. In addition, according to theoretical models aimed at unifying all four types of interaction, there is a hypothetical particle that carries a gravitational field, which is called the graviton. The peculiarity of the graviton is that it (according to the theory) participates only in gravitational interaction. Note that the theory associates two more hypothetical particles with quantum processes of gravitational interaction—gravitino and graviphoton. The experimental detection of gravitons, i.e., essentially, gravitational radiation, is extremely difficult due to its extremely weak interaction with matter.
Depending on their lifetime, elementary particles are divided into stable, quasi-stable and unstable (resonances).
Stable particles are the electron (its lifetime t > 10 21 years), proton (t > 10 31 years), neutrino and photon. Particles that decay due to electromagnetic and weak interactions are considered quasi-stable; their lifetime is t > 10 -20 s. Resonances are particles that decay as a result of strong interactions; their lifetime is in the range of 10 -22 ^10 -24 s.
Another type of subdivision of elementary particles is common. Systems of particles with zero and integer spin obey Bose-Einstein statistics, which is why such particles are usually called bosons. A collection of particles with half-integer spin is described by Fermi-Dirac statistics, hence the name of such particles - fermions.
Each elementary particle is characterized by a certain set of discrete physical quantities - quantum numbers. The characteristics common to all particles are mass m, lifetime t, spin J and electric charge Q. The spin of elementary particles takes values equal to integer or half-integer multiples of Planck's constant. The electric charges of particles are integer multiples of the electron charge, which is considered the elementary electric charge.
In addition, elementary particles are additionally characterized by so-called internal quantum numbers. Leptons are assigned a specific lepton charge L = ±1, hadrons with half-integer spin carry a baryon charge B = ±1 (hadrons with B = 0 form a subgroup of mesons).
An important quantum characteristic of hadrons is the internal parity P, which takes the value ±1 and reflects the symmetry property of the particle wave function with respect to spatial inversion (mirror image). Despite the non-conservation of parity in weak interactions, particles with good accuracy take internal parity values equal to either +1 or -1.
Hadrons are further divided into ordinary particles (proton, neutron, pi-mesons), strange particles (^-mesons, hyperons, some resonances), “charmed” and “beautiful” particles. They correspond to special quantum numbers: strangeness S, charm C and beauty b. These quantum numbers are introduced in accordance with the quark model to interpret the specific processes characteristic of these particles.
Among hadrons there are groups (families) of particles with similar masses, identical internal quantum numbers, but differing in electric charge. Such groups are called isotopic multiplets and are characterized by a common quantum number—isotopic spin, which, like ordinary spin, takes integer and half-integer values.
What is the already repeatedly mentioned quark model of hadrons?
The discovery of the pattern of grouping of hadrons into multiplets served as the basis for the assumption of the existence of special structural formations from which hadrons are built - quarks. Assuming the existence of such particles, we can assume that all hadrons are combinations of quarks. This bold and heuristically productive hypothesis was put forward in 1964 by the American physicist Murray Gell-Man. Its essence was the assumption of the presence of three fundamental particles with half-integer spin, which are the material for the construction of hadrons, u-, d- and s-quarks. Subsequently, based on new experimental data, the quark model of the structure of hadrons was supplemented with two more quarks, “charmed” (c) and “beautiful” (b). The existence of other types of quarks is considered possible. A distinctive feature of quarks is that they have fractional values of electric and baryon charges, which are not found in any of the known particles. All experimental results on the study of elementary particles are consistent with the quark model.
According to the quark model, baryons consist of three quarks, mesons - of a quark and an antiquark. Since some baryons are a combination of three quarks in the same state, which is prohibited by the Pauli principle (see above), each type ("flavor") of quark was assigned an additional internal quantum number "color". Each type of quark (“flavor” - u, d, s, c, b) can be in three “color” states. In connection with the use of color concepts, the theory of strong interaction of quarks is called quantum chromodynamics (from the Greek “color”).
We can assume that quarks are new elementary particles, and they claim to be truly elementary particles for the hadronic form of matter. However, the problem of observing free quarks and gluons remains unresolved. Despite systematic searches in cosmic rays at high-energy accelerators, it has not yet been possible to detect them in a free state. There are good reasons to believe that here physics has encountered a special natural phenomenon - the so-called confinement of quarks.
The point is that there are serious theoretical and experimental arguments in favor of the assumption that the forces of interaction between quarks do not weaken with distance. This means that infinitely more energy is required to separate quarks, therefore, the appearance of quarks in a free state is impossible. This circumstance gives quarks the status of completely special structural units of matter. Perhaps it is precisely starting from quarks that experimental observation of the stages of matter fragmentation is fundamentally impossible. The recognition of quarks as really existing objects of the material world not only represents a striking case of the primacy of the idea in relation to the existence of a material entity. The question arises of revising the table of fundamental world constants, since the charge of a quark is three times less than the charge of a proton, and therefore an electron.
Since the discovery of the positron, science has encountered antimatter particles. Today it is obvious that for all elementary particles with non-zero values of at least one of the quantum numbers, such as electric charge Q, lepton charge L, baryon charge B, strangeness S, charm C and beauty b, there are antiparticles with the same mass values , lifetime, spin, but with opposite signs of the above quantum numbers. Particles are known that are identical to their antiparticles; they are called truly neutral. Examples of truly neutral particles are the photon and one of the three pi-mesons (the other two are particle and antiparticle in relation to each other).
A characteristic feature of the interaction of particles and antiparticles is their annihilation upon collision, i.e. mutual destruction with the formation of other particles and the fulfillment of the laws of conservation of energy, momentum, charge, etc. A typical example of the annihilation of a pair is the process of transformation of an electron and its antiparticle - a positron - into electromagnetic radiation (in photons or gamma quanta). Pair annihilation occurs not only during electromagnetic interaction, but also during strong interaction. At high energies, light particles can annihilate to form heavier particles, provided that the total energy of the annihilating particles exceeds the threshold for the production of heavy particles (equal to the sum of their rest energies).
With strong and electromagnetic interactions, there is complete symmetry between particles and their antiparticles, i.e. all processes occurring between the former are also possible for the latter. Therefore, antiprotons and antineutrons can form the nuclei of antimatter atoms, i.e., in principle, antimatter can be built from antiparticles. An obvious question arises: if every particle has an antiparticle, then why are there no accumulations of antimatter in the studied region of the Universe? Indeed, their presence in the Universe, even somewhere “near” the Universe, could be judged by the powerful annihilation radiation coming to the Earth from the region of contact between matter and antimatter. However, modern astrophysics does not have data that would allow us to even assume the presence of regions filled with antimatter in the Universe.
How did the choice in favor of matter and to the detriment of antimatter occur in the Universe, although the laws of symmetry are basically fulfilled? The reason for this phenomenon, most likely, was precisely the violation of symmetry, i.e., fluctuation at the level of the fundamentals of matter.
One thing is clear: if such a fluctuation had not occurred, the fate of the Universe would have been sad - all its matter would have existed in the form of an endless cloud of photons resulting from the annihilation of particles of matter and antimatter.
Elementary particles, in a narrow sense, are particles that cannot be considered composed of other particles. In modern physics the term " elementary particles" is used in a broader sense: this is the name given to the smallest particles of matter, subject to the condition that they are not atoms (the exception is the proton); sometimes for this reason elementary particles called subnuclear particles. Most of these particles (more than 350 of them are known) are composite systems.
Elementary particles participate in electromagnetic, weak, strong and gravitational interactions. Due to the small masses elementary particles their gravitational interaction is usually not taken into account. All elementary particles divided into three main groups. The first consists of the so-called bosons - carriers of the electroweak interaction. This includes a photon, or a quantum of electromagnetic radiation. The rest mass of a photon is zero, therefore the speed of propagation of electromagnetic waves (including light waves) represents the maximum speed of propagation of a physical effect and is one of the fundamental physical constants; it is accepted that With= (299792458±1.2) m/s.
Second group elementary particles- leptons participating in electromagnetic and weak interactions. 6 leptons are known: , electron neutrino, muon, muon neutrino, heavy τ-lepton and the corresponding neutrino. The electron (symbol e) is considered the material carrier of the smallest mass in nature m e equal to 9.1×10 -28 g (in energy units ≈0.511 MeV) and the smallest negative electric charge e= 1.6×10 -19 Cl. Muons (symbol μ -) are particles with a mass of about 207 electron masses (105.7 MeV) and an electric charge equal to the electron charge; the heavy τ lepton has a mass of about 1.8 GeV. The three types of neutrinos corresponding to these particles are electron (symbol ν
e), muon (symbol ν μ) and τ-neutrino (symbol ν τ) are light (possibly massless) electrically neutral particles.
Each of the leptons corresponds to a lepton, which has the same values of mass, spin and other characteristics, but differs in the sign of the electric charge. There are (symbol e +) - antiparticle with respect to , positively charged (symbol μ +) and three types of antineutrino (symbols ) which are assigned the opposite sign of a special quantum number called lepton charge (see below).
The third group of elementary particles are hadrons; they participate in strong, weak and electromagnetic interactions. Hadrons are “heavy” particles with a mass significantly greater than the mass of an electron. This is the largest group elementary particles. Hadrons are divided into baryons - particles with spin ½ћ, mesons - particles with integer spin (0 or 1); as well as the so-called resonances - short-lived excited states of hadrons. Baryons include a proton (symbol p) - the nucleus of a hydrogen atom with a mass ~ 1836 times greater m e and equal to 1.672648×10 -24 g (≈938.3 MeV), and a positive electric charge equal to the charge of a neutron (symbol n) - an electrically neutral particle whose mass slightly exceeds the mass of a proton. Everything is built from protons and neutrons; it is the strong interaction that determines the connection of these particles with each other. In a strong interaction, a proton and a neutron have the same properties and are considered as two quantum states of one particle - a nucleon with isotopic spin ½ћ (see below). Baryons also include hyperons - elementary particles with a mass greater than the nucleon: the Λ-hyperon has a mass of 1116 MeV, the Σ-hyperon - 1190 MeV, the Θ-hyperon - 1320 MeV, the Ω-hyperon - 1670 MeV. Mesons have masses intermediate between the masses of a proton and an electron (π-meson, K-meson). There are neutral and charged mesons (with positive and negative elementary electric charge). According to their statistical properties, all mesons are classified as bosons.
Basic properties of elementary particles
Each elementary particle described by a set of discrete values of physical quantities (quantum numbers). General characteristics of all elementary particles- mass, lifetime, spin, electric charge.
Depending on life time elementary particles are divided into stable, quasi-stable and unstable (resonances). Stable (within the accuracy of modern measurements) are: electron (lifetime more than 5 × 10 21 years), proton (more than 10 31 years), photon and neutrino. Quasi-stable particles include particles that decay due to electromagnetic and weak interactions; their lifetimes are more than 10–20 s. Resonances decay due to strong interaction, their characteristic lifetimes are 10 -22 - 10 -24 s.
Internal characteristics (quantum numbers) elementary particles are lepton (symbol L) and baryon (symbol IN)charges; these numbers are considered to be strictly conserved quantities for all types of fundamental interactions. For leptons and their antiparticles L have opposite signs; for baryons IN= 1, for the corresponding antiparticles IN=-1.
Hadrons are characterized by the presence of special quantum numbers: “strangeness”, “charm”, “beauty”. Ordinary (non-strange) hadrons - proton, neutron, π-mesons. Within different groups of hadrons there are families of particles that are similar in mass and with similar properties with respect to the strong interaction, but with different electric charge values; The simplest example is a proton and a neutron. The general quantum number for such elementary particles- the so-called isotopic spin, which, like ordinary spin, takes integer and half-integer values. The special characteristics of hadrons also include internal parity, which takes values of ±1.
Important property elementary particles- their ability to undergo mutual transformations as a result of electromagnetic or other interactions. One of the types of mutual transformations is the so-called birth of a pair, or the formation of a particle and an antiparticle at the same time (in the general case, the formation of a pair elementary particles with opposite lepton or baryon charges). Possible processes of the birth of electron-positron pairs e - e +, muon pairs μ + μ - new heavy particles in collisions of leptons, formation from quarks cc- And bb-states (see below). Another type of interconversion elementary particles- annihilation of a pair during particle collisions with the formation of a finite number of photons (γ-quanta). Typically, 2 photons are produced when the total spin of colliding particles is zero and 3 photons are produced when the total spin is equal to 1 (a manifestation of the law of conservation of charge parity).
Under certain conditions, in particular at a low speed of colliding particles, the formation of a bound system is possible - positronium e - e + and muonium μ + e - . These are unstable systems, often called hydrogen-like. Their lifetime in a substance depends to a large extent on the properties of the substance, which makes it possible to use hydrogen-like atoms to study the structure of condensed matter and the kinetics of fast chemical reactions (see Meson chemistry, Nuclear chemistry).
Quark model of hadrons
A detailed examination of the quantum numbers of hadrons for the purpose of their classification led to the conclusion that strange hadrons and ordinary hadrons together form associations of particles with similar properties, called unitary multiplets. The numbers of particles included in them are 8 (octet) and 10 (decuplet). The particles that make up the unitary multiplet have the same internal parity, but differ in the values of the electric charge (particles of the isotopic multiplet) and strangeness. Symmetry properties are associated with unitary groups; their discovery was the basis for the conclusion about the existence of special structural units from which hadrons are built - quarks. Hadrons are believed to be combinations of 3 fundamental particles with spin ½: n-quarks, d-quarks and s-quarks. Thus, mesons are made up of a quark and an antiquark, baryons are made up of 3 quarks.
The assumption that hadrons are composed of 3 quarks was made in 1964 (J. Zweig and, independently, M. Gell-Mann). Subsequently, two more quarks were included in the model of the structure of hadrons (in particular, in order to avoid conflicts with the Pauli principle) - “charm” ( With) and beautiful" ( b), and also introduced special characteristics of quarks - “flavor” and “color”. Quarks, acting as components of hadrons, have not been observed in a free state. All the diversity of hadrons is due to various combinations n-, d-, s-, With- And b-quarks forming connected states. Ordinary hadrons (proton, neutron, π-mesons) correspond to connected states constructed from n- And d-quarks. Presence in the hadron along with n- And d-quarks of one s-, With- or b-quark means that the corresponding hadron is "strange", "charmed" or "beautiful".
The quark model of hadron structure was confirmed as a result of experiments conducted in the late 60s - early 70s. XX century Quarks actually began to be considered new elementary particles- true elementary particles for the hadronic form of matter. The unobservability of free quarks, apparently, is of a fundamental nature and gives reason to assume that they are those elementary particles, which close the chain of structural components of a substance. There are theoretical and experimental arguments in favor of the fact that the forces acting between quarks do not weaken with distance, i.e. Separating quarks from each other requires infinitely large energy or, in other words, the emergence of quarks in a free state is impossible. This makes them a completely new type of structural units of matter. It is possible that quarks act as the last stage of matter fragmentation.
Brief historical information
First open elementary particle there was an electron - the carrier of a negative electric charge in atoms (J.J. Thomson, 1897). In 1919, E. Rutherford discovered protons among particles knocked out of atomic nuclei. Neutrons were discovered in 1932 by J. Chadwick. In 1905, A. Einstein postulated that electromagnetic radiation is a flow of individual quanta (photons) and on this basis explained the laws of the photoelectric effect. Existence as special elementary particle first proposed by W. Pauli (1930); electronic