, electromagnetic and gravitational

Protons take part in thermonuclear reactions, which are the main source of energy generated by stars. In particular, the reactions pp-cycle, which is the source of almost all the energy emitted by the Sun, come down to the combination of four protons into a helium-4 nucleus with the transformation of two protons into neutrons.

In physics, the proton is denoted p(or p+ ). The chemical designation of the proton (considered as a positive hydrogen ion) is H + , the astrophysical designation is HII.

Opening

Proton properties

The ratio of the proton and electron masses, equal to 1836.152 673 89(17) , with an accuracy of 0.002%, is equal to the value 6π 5 = 1836.118…

The internal structure of the proton was first experimentally studied by R. Hofstadter by studying the collisions of a beam of high-energy electrons (2 GeV) with protons ( Nobel Prize in Physics 1961). The proton consists of a heavy core (core) with a radius of cm, with a high mass and charge density, which carries ≈ 35% (\displaystyle \approx 35\,\%) the electric charge of the proton and the relatively rarefied shell surrounding it. At a distance from ≈ 0 , 25 ⋅ 10 − 13 (\displaystyle \approx 0(,)25\cdot 10^(-13)) before ≈ 1 , 4 ⋅ 10 − 13 (\displaystyle \approx 1(,)4\cdot 10^(-13)) see this shell consists mainly of virtual ρ - and π - mesons, carrying ≈ 50% (\displaystyle \approx 50\,\%) the electric charge of the proton, then up to a distance ≈ 2 , 5 ⋅ 10 − 13 (\displaystyle \approx 2(,)5\cdot 10^(-13)) cm extends a shell of virtual ω - and π -mesons, carrying ~ 15% of the electric charge of the proton.

The pressure at the center of the proton, created by quarks, is about 10 35 Pa (10 30 atmospheres), that is, higher than the pressure inside neutron stars.

The magnetic moment of a proton is measured by measuring the ratio of the resonant frequency of the precession of the magnetic moment of the proton in a given uniform magnetic field and the cyclotron frequency of the proton in a circular orbit in the same field.

The proton is associated with three physical quantities having the dimension of length:

Measurements of the proton radius using ordinary hydrogen atoms, carried out by various methods since the 1960s, have led (CODATA -2014) to the result 0.8751 ± 0.0061 femtometer(1 fm = 10 −15 m) . The first experiments with muonic hydrogen atoms (where the electron is replaced by a muon) gave a 4% lower result for this radius, 0.84184 ± 0.00067 fm. The reasons for this difference are still unclear.

The so-called weak proton charge Q w ≈ 1 − 4 sin 2 θ W, which determines its participation in weak interactions through the exchange Z 0-boson (similar to how the electric charge of a particle determines its participation in electromagnetic interactions by exchanging a photon) is 0.0719 ± 0.0045, according to experimental measurements of parity violation during the scattering of polarized electrons by protons. The measured value agrees within the experimental error with the theoretical predictions of the Standard Model (0.0708 ± 0.0003 ) .

Stability

The free proton is stable, experimental studies did not reveal any signs of its decay (the lower limit on the lifetime is 2.9⋅10 29 years regardless of the decay channel , 8.2⋅10 33 years for decay into a positron and a neutral pion , 6.6⋅10 33 years for decay into positive muon and neutral pion). Since the proton is the lightest of the baryons, the stability of the proton is a consequence of the law of conservation of the baryon number - the proton cannot decay into any lighter particles (for example, into a positron and a neutrino) without violating this law. However, many theoretical extensions of the Standard Model predict processes (not yet observed) that would result in nonconservation of the baryon number and, consequently, in the decay of the proton.

A proton bound in the atomic nucleus is able to capture an electron from the electronic K-, L- or M-shell of the atom (the so-called " electron capture"). A proton of an atomic nucleus, having absorbed an electron, turns into a neutron and simultaneously emits a neutrino: p+e − →+ν e . A “hole” in the K-, L- or M-layer, formed during electron capture, is filled with an electron from one of the overlying electron layers of the atom with the emission of characteristic X-rays corresponding to the atomic number Z− 1 , and/or Auger electrons . More than 1000 isotopes are known from 7
4 to 262
105 decaying by electron capture. At sufficiently high available decay energies (above 2m e c 2 ≈ 1.022 MeV) a competing decay channel opens - positron decay p → +e ++ν e . It should be emphasized that these processes are possible only for a proton in some nuclei, where the missing energy is replenished by the transition of the resulting neutron to a lower nuclear shell; for a free proton they are forbidden by the energy conservation law.

The source of protons in chemistry are mineral (nitric, sulfuric, phosphoric and others) and organic (formic, acetic, oxalic and others) acids. V aqueous solution acids are capable of dissociating with the elimination of a proton, forming a hydronium cation.

In the gas phase, protons are obtained by ionization - the detachment of an electron from a hydrogen atom. The ionization potential of an unexcited hydrogen atom is 13.595 eV. When molecular hydrogen is ionized by fast electrons at atmospheric pressure and room temperature, a molecular hydrogen ion (H 2 +) is initially formed - a physical system consisting of two protons held together at a distance of 1.06 by one electron. The stability of such a system, according to Pauling, is caused by the resonance of an electron between two protons with a "resonant frequency" equal to 7·10 14 s −1 . When the temperature rises to several thousand degrees, the composition of hydrogen ionization products changes in favor of protons - H + .

Application

see also

Notes

1. http://physics.nist.gov/cuu/Constants/Table/allascii.txt Fundamental Physical Constants --- Complete Listing
2. CODATA Value: proton mass
3. CODATA Value: proton mass in u
4. Ahmed S.; et al. (2004). “Constraints on Nucleon Decay via Invisible Modes from the Sudbury Neutrino Observatory”. Physical Review Letters. 92 (10): 102004. arXiv : hep-ex/0310030. Bibcode :2004PhRvL..92j2004A . DOI:10.1103/PhysRevLett.92.102004. PMID.
5. CODATA Value: proton mass energy equivalent in MeV
6. CODATA Value: proton-electron mass ratio
7. , With. 67.
8. Hofstadter P. Structure of nuclei and nucleons // UFN . - 1963. - T. 81, No. 1. - S. 185-200. - ISSN. - URL: http://ufn.ru/ru/articles/1963/9/e/
9. Shchelkin K.I. Virtual processes and the structure of the nucleon // Physics of the microworld - M.: Atomizdat, 1965. - P. 75.
10. Zhdanov G. B. Elastic Scatterings, Peripheral Interactions and Resonons // High Energy Particles. High energies in space and laboratories - M.: Nauka, 1965. - P. 132.
11. Burkert V. D. , Elouadrhiri L. , Girod F. X. The pressure distribution inside the proton // Nature. - 2018. - May (vol. 557, no. 7705). - P. 396-399. - DOI:10.1038/s41586-018-0060-z .
12. Bethe, G., Morrison F. Elementary theory of the nucleus. - M: IL, 1956. - S. 48.

Protons take part in thermonuclear reactions, which are the main source of energy generated by stars. In particular, the reactions pp-cycle, which is the source of almost all the energy emitted by the Sun, come down to the combination of four protons into a helium-4 nucleus with the transformation of two protons into neutrons.

In physics, the proton is denoted p(or p+ ). The chemical designation of the proton (considered as a positive hydrogen ion) is H + , the astrophysical designation is HII.

Opening

Proton properties

The ratio of the proton and electron masses, equal to 1836.152 673 89(17) , with an accuracy of 0.002%, is equal to the value 6π 5 = 1836.118…

The internal structure of the proton was first experimentally investigated by R. Hofstadter by studying the collisions of a beam of high-energy electrons (2 GeV) with protons (Nobel Prize in Physics 1961). The proton consists of a heavy core (core) with a radius of cm, with a high mass and charge density, which carries ≈ 35% (\displaystyle \approx 35\,\%) the electric charge of the proton and the relatively rarefied shell surrounding it. At a distance from ≈ 0 , 25 ⋅ 10 − 13 (\displaystyle \approx 0(,)25\cdot 10^(-13)) before ≈ 1 , 4 ⋅ 10 − 13 (\displaystyle \approx 1(,)4\cdot 10^(-13)) see this shell consists mainly of virtual ρ - and π - mesons, carrying ≈ 50% (\displaystyle \approx 50\,\%) the electric charge of the proton, then up to a distance ≈ 2 , 5 ⋅ 10 − 13 (\displaystyle \approx 2(,)5\cdot 10^(-13)) cm extends a shell of virtual ω - and π -mesons, carrying ~ 15% of the electric charge of the proton.

The pressure at the center of the proton, created by quarks, is about 10 35 Pa (10 30 atmospheres), that is, higher than the pressure inside neutron stars.

The magnetic moment of a proton is measured by measuring the ratio of the resonant frequency of the precession of the magnetic moment of the proton in a given uniform magnetic field and the cyclotron frequency of the proton in a circular orbit in the same field.

The proton is associated with three physical quantities having the dimension of length:

Measurements of the proton radius using ordinary hydrogen atoms, carried out by various methods since the 1960s, have led (CODATA -2014) to the result 0.8751 ± 0.0061 femtometer(1 fm = 10 −15 m) . The first experiments with muonic hydrogen atoms (where the electron is replaced by a muon) gave a 4% lower result for this radius, 0.84184 ± 0.00067 fm. The reasons for this difference are still unclear.

Stability

The free proton is stable, experimental studies have not revealed any signs of its decay (the lower limit on the lifetime is 2.9⋅10 29 years regardless of the decay channel , 1.6⋅10 34 years for decay into a positron and a neutral pion , 7.7⋅ 10 33 years for the decay into a positive muon and a neutral pion). Since the proton is the lightest of the baryons, the stability of the proton is a consequence of the law of conservation of the baryon number - the proton cannot decay into any lighter particles (for example, into a positron and a neutrino) without violating this law. However, many theoretical extensions of the Standard Model predict processes (not yet observed) that would result in nonconservation of the baryon number and, consequently, in the decay of the proton.

A proton bound in the atomic nucleus is able to capture an electron from the electronic K-, L- or M-shell of the atom (the so-called " electron capture"). A proton of an atomic nucleus, having absorbed an electron, turns into a neutron and simultaneously emits a neutrino: p+e − →+ν e . A “hole” in the K-, L- or M-layer, formed during electron capture, is filled with an electron from one of the overlying electron layers of the atom with the emission of characteristic X-rays corresponding to the atomic number Z− 1 , and/or Auger electrons . More than 1000 isotopes are known from 7
4 to 262
105 decaying by electron capture. At sufficiently high available decay energies (above 2m e c 2 ≈ 1.022 MeV) a competing decay channel opens - positron decay p → +e ++ν e . It should be emphasized that these processes are possible only for a proton in some nuclei, where the missing energy is replenished by the transition of the resulting neutron to a lower nuclear shell; for a free proton they are forbidden by the energy conservation law.

The source of protons in chemistry are mineral (nitric, sulfuric, phosphoric and others) and organic (formic, acetic, oxalic and others) acids. In an aqueous solution, acids are capable of dissociation with the elimination of a proton, forming a hydronium cation.

In the gas phase, protons are obtained by ionization - the detachment of an electron from a hydrogen atom. The ionization potential of an unexcited hydrogen atom is 13.595 eV. When molecular hydrogen is ionized by fast electrons at atmospheric pressure and room temperature, a molecular hydrogen ion (H 2 +) is initially formed - a physical system consisting of two protons held together at a distance of 1.06 by one electron. The stability of such a system, according to Pauling, is caused by the resonance of an electron between two protons with a "resonant frequency" equal to 7·10 14 s −1 . When the temperature rises to several thousand degrees, the composition of hydrogen ionization products changes in favor of protons - H + .

Application

Beams of accelerated protons are used in experimental particle physics (the study of scattering processes and obtaining beams of other particles), in medicine (proton therapy for oncological diseases).

see also

Notes

1. http://physics.nist.gov/cuu/Constants/Table/allascii.txt Fundamental Physical Constants --- Complete Listing
2. CODATA Value: proton mass
3. CODATA Value: proton mass in u
4. Ahmed S.; et al. (2004). “Constraints on Nucleon Decay via Invisible Modes from the Sudbury Neutrino Observatory”. Physical Review Letters. 92 (10): 102004. arXiv : hep-ex/0310030. Bibcode :2004PhRvL..92j2004A . DOI:10.1103/PhysRevLett.92.102004. PMID.
5. CODATA Value: proton mass energy equivalent in MeV
6. CODATA Value: proton-electron mass ratio
7. , With. 67.
8. Hofstadter P. Structure of nuclei and nucleons // UFN . - 1963. - T. 81, No. 1. - S. 185-200. - ISSN. - URL: http://ufn.ru/ru/articles/1963/9/e/
9. Shchelkin K.I. Virtual processes and the structure of the nucleon // Physics of the microworld - M.: Atomizdat, 1965. - P. 75.
10. Zhdanov G. B. Elastic Scatterings, Peripheral Interactions and Resonons // High Energy Particles. High energies in space and laboratories - M.: Nauka, 1965. - P. 132.
11. Burkert V. D. , Elouadrhiri L. , Girod F. X. The pressure distribution inside the proton // Nature. - 2018. - May (vol. 557, no. 7705). - P. 396-399. - DOI:10.1038/s41586-018-0060-z .
12. Bethe, G., Morrison F. Elementary theory of the nucleus. - M: IL, 1956. - S. 48.

By studying the structure of matter, physicists learned what atoms are made of, got to the atomic nucleus and split it into protons and neutrons. All these steps were given quite easily - it was only necessary to disperse the particles to the required energy, push them against each other, and then they themselves fell apart into their component parts.

But with protons and neutrons, this trick has not worked. Although they are composite particles, they cannot be "broken apart" in any even the most violent collision. Therefore, it took physicists decades to come up with different ways to look inside the proton, to see its structure and shape. Today, the study of the structure of the proton is one of the most active areas of elementary particle physics.

Nature gives hints

The history of studying the structure of protons and neutrons dates back to the 1930s. When, in addition to protons, neutrons were discovered (1932), by measuring their mass, physicists were surprised to find that it is very close to the mass of a proton. Moreover, it turned out that protons and neutrons "feel" the nuclear interaction in exactly the same way. So much the same that, from the point of view of nuclear forces, the proton and neutron can be considered as if two manifestations of the same particle - the nucleon: the proton is an electrically charged nucleon, and the neutron is a neutral nucleon. Swap protons for neutrons and nuclear forces will (almost) not notice anything.

Physicists express this property of nature as symmetry - the nuclear interaction is symmetrical with respect to the replacement of protons by neutrons, just as a butterfly is symmetrical with respect to the replacement of left for right. This symmetry, in addition to playing an important role in nuclear physics, was actually the first hint that nucleons have an interesting internal structure. True, then, in the 1930s, physicists did not realize this hint.

Understanding came later. It began with the fact that in the 1940s and 50s, in the reactions of proton collisions with the nuclei of various elements, scientists were surprised to discover more and more new particles. Not protons, not neutrons, pi-mesons not discovered by that time, which keep nucleons in nuclei, but some completely new particles. For all their diversity, these new particles had two common properties. First, they, like nucleons, very willingly participated in nuclear interactions - now such particles are called hadrons. And secondly, they were extremely unstable. The most unstable of them decayed into other particles in just a trillionth of a nanosecond, not even having time to fly by the size of an atomic nucleus!

For a long time, the "zoo" of hadrons was a complete hodgepodge. In the late 1950s, physicists already recognized quite a lot of different types of hadrons, began to compare them with each other, and suddenly saw a certain general symmetry, even periodicity, in their properties. It was conjectured that inside all hadrons (including nucleons) there are some simple objects, which are called "quarks". Combining quarks in different ways, it is possible to obtain different hadrons, moreover, of exactly the same type and with such properties that were found in the experiment.

What makes a proton a proton?

After physicists discovered the quark structure of hadrons and learned that quarks come in several different varieties, it became clear that many different particles could be constructed from quarks. So no one was surprised when subsequent experiments continued to find new hadrons one after another. But among all the hadrons, a whole family of particles was found, consisting, just like the proton, of only two u-quarks and one d-quark. A sort of "brothers" of the proton. And here the physicists were in for a surprise.

Let's make one simple observation first. If we have several objects consisting of the same "bricks", then heavier objects contain more "bricks", and lighter ones - less. This is a very natural principle, which may be called the principle of combination or the principle of superstructure, and it is perfectly executed as in Everyday life, as well as in physics. It manifests itself even in the structure of atomic nuclei - after all, heavier nuclei simply consist of a larger number of protons and neutrons.

However, at the level of quarks, this principle does not work at all, and, admittedly, physicists have not yet fully figured out why. It turns out that the heavy brothers of the proton also consist of the same quarks as the proton, although they are one and a half or even two times heavier than the proton. They differ from the proton (and differ from each other) not composition, but mutual location quarks, by the state in which these quarks are relative to each other. It is enough to change the mutual position of the quarks - and we will get another, noticeably heavier, particle from the proton.

But what happens if you still take and collect together more than three quarks? Will a new heavy particle be obtained? Surprisingly, it will not work - the quarks will break in threes and turn into several disparate particles. For some reason, nature "does not like" to combine many quarks into one! Only very recently, literally in last years, hints began to appear that some multiquark particles do exist, but this only emphasizes how much nature does not like them.

A very important and profound conclusion follows from this combinatorics - the mass of hadrons does not at all consist of the mass of quarks. But if the mass of a hadron can be increased or decreased by simply recombining its building blocks, then the quarks themselves are not at all responsible for the mass of hadrons. Indeed, in subsequent experiments, it was possible to find out that the mass of the quarks themselves is only about two percent of the mass of the proton, and the rest of the gravity arises due to the force field (special particles - gluons) that bind the quarks together. By changing the mutual arrangement of quarks, for example, by moving them away from each other, we thereby change the gluon cloud, make it more massive, which is why the mass of the hadron increases (Fig. 1).

What is going on inside a fast flying proton?

Everything described above concerns a motionless proton, in the language of physicists, this is the structure of a proton in its rest frame. However, in the experiment, the structure of the proton was first discovered in other conditions - inside fast flying proton.

In the late 1960s, in particle collision experiments at accelerators, it was noticed that protons flying at near-light speed behaved as if the energy inside them was not distributed evenly, but concentrated in separate compact objects. The famous physicist Richard Feynman proposed to call these clumps of matter inside protons partons(from English part- part).

In subsequent experiments, many of the properties of partons were studied—for example, their electrical charge, their number, and the proportion of proton energy each carries. It turns out that charged partons are quarks and neutral partons are gluons. Yes, yes, the very gluons, which in the rest frame of the proton simply "served" the quarks, attracting them to each other, are now independent partons and, along with the quarks, carry the "matter" and energy of a rapidly flying proton. Experiments have shown that approximately half of the energy is stored in quarks, and half in gluons.

Partons are most conveniently studied in the collision of protons with electrons. The fact is that, unlike a proton, an electron does not participate in strong nuclear interactions and its collision with a proton looks very simple: the electron emits a virtual photon for a very short time, which crashes into a charged parton and eventually generates big number particles (Fig. 2). We can say that the electron is an excellent scalpel for "opening" the proton and splitting it into separate parts - however, only for a very short time. Knowing how often such processes occur at the accelerator, it is possible to measure the number of partons inside the proton and their charges.

Who are the real partons?

And here we come to another amazing discovery that physicists have made while studying elementary particle collisions at high energies.

V normal conditions the question of what this or that object consists of has a universal answer for all frames of reference. For example, a water molecule consists of two hydrogen atoms and one oxygen atom - and it does not matter whether we are looking at a stationary or moving molecule. However, this rule - it would seem so natural! - violated if we are talking about elementary particles moving at speeds close to the speed of light. In one frame of reference, a complex particle may consist of one set of subparticles, and in another frame of reference, of another. It turns out that composition is a relative concept!

How can this be? The key here is one important property: the number of particles in our world is not fixed - particles can be born and disappear. For example, if two electrons with a sufficiently high energy are pushed together, then in addition to these two electrons, either a photon, or an electron-positron pair, or some other particles can be born. All this is allowed by quantum laws, and this is exactly what happens in real experiments.

But this "law of non-conservation" of particles works in collisions particles. But how is it that the same proton with different points of vision looks like it consists of a different set of particles? The fact is that a proton is not just three quarks put together. There is a gluon force field between quarks. In general, a force field (like, for example, a gravitational or electric field) is a kind of material “entity” that permeates space and allows particles to exert force on each other. In quantum theory, the field also consists of particles, though special ones - virtual ones. The number of these particles is not fixed, they are constantly "budding" from quarks and being absorbed by other quarks.

resting The proton can indeed be thought of as three quarks, between which gluons jump. But if we look at the same proton from a different frame of reference, as if from the window of a “relativistic train” passing by, we will see a completely different picture. Those virtual gluons that glued the quarks together will seem to be less virtual, "more real" particles. They, of course, are still born and absorbed by quarks, but at the same time they live on their own for some time, flying next to the quarks, like real particles. What looks like a simple force field in one frame of reference turns into a stream of particles in another frame! Note that we do not touch the proton itself, but only look at it from a different frame of reference.

Further more. The closer the speed of our "relativistic train" to the speed of light, the more amazing picture inside the proton we will see. As we approach the speed of light, we will notice that there are more and more gluons inside the proton. Moreover, they sometimes split into quark-antiquark pairs, which also fly side by side and are also considered partons. As a result, an ultrarelativistic proton, i.e., a proton moving relative to us at a speed very close to the speed of light, appears as interpenetrating clouds of quarks, antiquarks and gluons that fly together and seem to support each other (Fig. 3).

The reader familiar with the theory of relativity may be worried. All physics is based on the principle that any process proceeds in the same way in all inertial frames of reference. And here it turns out that the composition of the proton depends on the frame of reference from which we observe it?!

Yes, that's right, but it doesn't violate the principle of relativity in any way. The results of physical processes - for example, which particles and how many are born as a result of a collision - do turn out to be invariant, although the composition of the proton depends on the frame of reference.

This situation, unusual at first glance, but satisfying all the laws of physics, is schematically illustrated in Figure 4. It shows how the collision of two high-energy protons looks like in different systems reference: in the rest frame of one proton, in the center of mass frame, in the rest frame of another proton. The interaction between protons is carried out through a cascade of splitting gluons, but only in one case this cascade is considered the “inside” of one proton, in the other case it is part of another proton, and in the third case it is just an object exchanged between two protons. This cascade exists, it is real, but which part of the process it should be attributed to depends on the frame of reference.

3D portrait of a proton

All the results that we have just described were based on experiments performed quite a long time ago - in the 60s and 70s of the last century. It would seem that since then everything should already be studied and all questions should find their answers. But no - the device of the proton is still one of the most interesting topics in particle physics. Moreover, in recent years, interest in it has increased again, because physicists have figured out how to get a "three-dimensional" portrait of a fast moving proton, which turned out to be much more complicated than a portrait of a stationary proton.

Classical proton collision experiments tell only about the number of partons and their energy distribution. In such experiments, partons participate as independent objects, which means that it is impossible to learn from them how partons are located relative to each other, how exactly they add up to a proton. It can be said that for a long time only a “one-dimensional” portrait of a fast-flying proton was available to physicists.

In order to build a real, three-dimensional, portrait of the proton and to know the distribution of partons in space, much more subtle experiments are required than those that were possible 40 years ago. Physicists have learned to perform such experiments quite recently, literally in the last decade. They realized that among the huge number of different reactions that occur when an electron collides with a proton, there is one special reaction - deep virtual Compton scattering, - which will be able to tell about the three-dimensional structure of the proton.

In general, Compton scattering, or the Compton effect, is called elastic collision photon with some particle, such as a proton. It looks like this: a photon arrives, is absorbed by a proton, which briefly goes into an excited state, and then returns to its original state, emitting a photon in some direction.

Compton scattering of ordinary light photons does not lead to anything interesting - it is a simple reflection of light from a proton. In order to "come into play" the internal structure of the proton and "feel" the distribution of quarks, it is necessary to use photons of very high energy - billions of times more than in ordinary light. And just such photons - however, virtual - are easily generated by an incident electron. If we now combine one with the other, then we get deep-virtual Compton scattering (Fig. 5).

The main feature of this reaction is that it does not destroy the proton. The incident photon does not just hit the proton, but, as it were, carefully feels it and then flies away. The direction in which it flies away and what part of the energy the proton takes away from it depends on the structure of the proton, on the relative position of the partons inside it. That is why, by studying this process, it is possible to restore the three-dimensional appearance of the proton, as if "to fashion its sculpture."

True, it is very difficult for an experimental physicist to do this. The desired process occurs quite rarely, and it is difficult to register it. The first experimental data on this reaction were obtained only in 2001 at the HERA accelerator in the German accelerator complex DESY in Hamburg; the new data series is now being processed by experimenters. However, already today, based on the first data, theorists draw three-dimensional distributions of quarks and gluons in the proton. Physical quantity, about which physicists used to build only assumptions, finally began to “appear” from the experiment.

Are there any unexpected discoveries in this area? It is likely that yes. As an illustration, let's say that in November 2008 an interesting theoretical article appeared, which states that a fast-flying proton should not look like a flat disk, but a biconcave lens. This happens because the partons sitting in the central region of the proton are more compressed in the longitudinal direction than the partons sitting on the edges. It would be very interesting to test these theoretical predictions experimentally!

Why is all this interesting to physicists?

Why do physicists need to know exactly how matter is distributed inside protons and neutrons?

First, this is required by the very logic of the development of physics. There are many amazingly complex systems in the world that modern theoretical physics cannot yet fully cope with. Hadrons are one such system. Understanding the structure of hadrons, we hone the ability of theoretical physics, which may well turn out to be universal and perhaps help in something completely different, for example, in the study of superconductors or other materials with unusual properties.

Secondly, there is an immediate benefit for nuclear physics. Despite almost a century of history of studying atomic nuclei, theorists still do not know the exact law of the interaction of protons and neutrons.

They have to partly guess this law on the basis of experimental data, and partly construct it on the basis of knowledge about the structure of nucleons. This is where new data on the three-dimensional structure of nucleons will help.

Thirdly, a few years ago, physicists managed to obtain nothing less than a new aggregate state of matter - quark-gluon plasma. In this state, quarks do not sit inside individual protons and neutrons, but freely walk around the entire bunch of nuclear matter. It can be achieved, for example, as follows: heavy nuclei are accelerated in the accelerator to a speed very close to the speed of light, and then they collide head-on. In this collision, for a very short time, a temperature of trillions of degrees arises, which melts the nuclei into a quark-gluon plasma. So, it turns out that the theoretical calculations of this nuclear melting require a good knowledge of the three-dimensional structure of nucleons.

Finally, these data are very necessary for astrophysics. When heavy stars explode at the end of their lives, they often leave extremely compact objects - neutron and possibly quark stars. The core of these stars consists entirely of neutrons, and perhaps even of cold quark-gluon plasma. Such stars have long been discovered, but what happens inside them can only be guessed at. So a good understanding of quark distributions can lead to progress in astrophysics as well.

Proton (elementary particle)

The field theory of elementary particles, acting within the framework of SCIENCE, relies on a foundation proven by PHYSICS:

• classical electrodynamics,
• Quantum mechanics (without virtual particles that contradict the law of conservation of energy),
• Conservation laws are the fundamental laws of physics.

This is the fundamental difference between the scientific approach used by the field theory of elementary particles - a true theory must strictly operate within the laws of nature: this is what SCIENCE is all about.

Using elementary particles that do not exist in nature, inventing fundamental interactions that do not exist in nature, or replacing the interactions that exist in nature with fabulous ones, ignoring the laws of nature, doing mathematical manipulations on them (creating the appearance of science) - this is the lot of FAIRY TALES masquerading as science. As a result, physics slipped into the world of mathematical fairy tales. Fairy-tale characters of the Standard Model (quarks with gluons), together with fairy-tale gravitons and fairy tales of the "Quantum Theory" have already penetrated into physics textbooks - and mislead children, passing off mathematical fairy tales as reality. Proponents of an honest New Physics tried to resist this, but the forces were not equal. And so it was until 2010 before the advent of the field theory of elementary particles, when the struggle for the revival of PHYSICS-SCIENCE moved to the level of open opposition to the true scientific theory with mathematical fairy tales that seized power in the physics of the microworld (and not only).

But mankind would not have known about the achievements of New Physics without the Internet, search engines and the opportunity to freely speak the truth on the pages of the site. As for publications that make money on science, who reads them today for money, when it is possible to quickly and freely obtain the required information on the Internet.

1 Proton is an elementary particle
2 When physics remained a science
3 Proton in physics
4 Proton radius
5 Magnetic moment of the proton
6 Proton electric field

6.1 Electric field of a proton in the far zone
6.2 Electric charges of the proton
6.3 Electric field of a proton in the near field

7 Proton rest mass
8 Proton lifetime
9 The truth about the Standard Model
10 New Physics: Proton - summary

Ernest Rutherford in 1919, irradiating nitrogen nuclei with alpha particles, observed the formation of hydrogen nuclei. Rutherford called the particle formed as a result of the collision a proton. The first photographs of proton traces in a cloud chamber were taken in 1925 by Patrick Blackett. But the hydrogen ions themselves (which is what protons are) were known long before Rutherford's experiments.
Today, in the 21st century, physics has much more to say about protons.

1 Proton is an elementary particle

The ideas of physics about the structure of the proton have changed as physics has developed.
Initially, physics considered the proton to be an elementary particle, and so it was until 1964, when GellMann and Zweig independently proposed the quark hypothesis.

Initially, the quark model of hadrons was limited to only three hypothetical quarks and their antiparticles. This made it possible to correctly describe the spectrum of elementary particles known at that time, without taking into account leptons, which did not fit into the proposed model and therefore were recognized as elementary, along with quarks. The price for this was the introduction of fractional electric charges that do not exist in nature. Then, with the development of physics and the receipt of new experimental data, the quark model gradually grew, transformed, eventually turning into the Standard Model.

Physicists diligently engaged in the search for new hypothetical particles. The search for quarks was carried out in cosmic rays, in nature (since their fractional electric charge cannot be compensated), and in accelerators.
Decades passed, the power of accelerators grew, and the result of the search for hypothetical quarks was always the same: quarks are NOT found in nature.

Seeing the prospect of the demise of the quark (and then the Standard) model, its supporters invented and slipped mankind a fairy tale that traces of quarks are observed in some experiments. - It is impossible to verify this information - the experimental data are processed using the Standard Model, and it will always give out something for what it needs. The history of physics knows examples when, instead of one particle, they slipped another - the last such manipulation of experimental data was the slipping of a vector meson as a fabulous Higgs boson, allegedly responsible for the mass of particles, but at the same time not creating their gravitational field. For this mathematical fairy tale, they even gave the Nobel Prize in Physics. In our case, standing waves of alternating electro magnetic field, about which the wave theories of elementary particles were written.

When the throne under the standard model staggered again, its supporters invented and slipped humanity a new fairy tale for the smallest, called "Confinement". Any thinking person will immediately see in it a mockery of the law of conservation of energy - a fundamental law of nature. But supporters of the Standard Model do not want to see the REALITY.

2 When physics remained a science

When physics was still a science in it, the truth was determined not by the opinion of the majority - but by experiment. This is the fundamental difference between PHYSICS-SCIENCE and mathematical fairy tales masquerading as physics.
All experiments to search for hypothetical quarks(except, of course, slipping your beliefs, under the guise of experimental data) clearly showed: there are NO quarks in nature.

Now supporters of the Standard Model are trying to replace the result of all experiments, which has become a verdict for the Standard Model, with their collective opinion, passing it off as reality. But no matter how much the fairy tale twists, the end will still be. The only question is what kind of end it will be: supporters of the Standard Model will show reason, courage and change their positions following the unanimous verdict of experiments (or rather: the verdict of NATURE), or they will be sent to history under general laughter New Physics - Physics of the 21st century like storytellers who tried to fool all of humanity. The choice is theirs.

Now about the proton itself.

3 Proton in physics

Proton - elementary particle quantum number L=3/2 (spin = 1/2) - baryon group, proton subgroup, electric charge +e (systematization according to the field theory of elementary particles).
According to the field theory of elementary particles (a theory built on a scientific foundation and the only one that received the correct spectrum of all elementary particles), a proton consists of a rotating polarized alternating electromagnetic field with a constant component. All the unsubstantiated statements of the Standard Model that the proton allegedly consists of quarks have nothing to do with reality. - Physics has experimentally proven that the proton has electromagnetic fields, and also the gravitational field. The fact that elementary particles do not just possess - but consist of electromagnetic fields, physics brilliantly guessed 100 years ago, but it was not possible to build a theory until 2010. Now, in 2015, the theory of gravity of elementary particles also appeared, which established the electromagnetic nature of gravity and received the equations of the gravitational field of elementary particles, different from the equations of gravity, on the basis of which more than one mathematical fairy tale in physics was built.

At the moment, the field theory of elementary particles (unlike the Standard Model) does not contradict experimental data on the structure and spectrum of elementary particles and therefore can be considered by physics as a theory that works in nature.

The structure of the electromagnetic field of the proton(E-constant electric field, H-constant magnetic field, yellow color indicates alternating electromagnetic field)
Energy balance (percentage of total internal energy):

• constant electric field (E) - 0.346%,
• permanent magnetic field (H) - 7.44%,
• alternating electromagnetic field - 92.21%.

It follows that for a proton m 0~ =0.9221m 0 and about 8 percent of its mass is concentrated in constant electric and magnetic fields. The ratio between the energy concentrated in a constant magnetic field of a proton and the energy concentrated in a constant electric field is 21.48. This explains the presence of nuclear forces in the proton.

The electric field of a proton consists of two regions: an outer region with a positive charge and an inner region with a negative charge. The difference between the charges of the outer and inner regions determines the total electric charge of the proton +e. Its quantization is based on the geometry and structure of elementary particles.

And this is how the fundamental interactions of elementary particles that really exist in nature look like:

4 Proton radius

The field theory of elementary particles defines the radius (r) of a particle as the distance from the center to the point where the maximum mass density is reached.

For a proton, this will be 3.4212 ∙ 10 -16 m. To this we must add the thickness of the electromagnetic field layer, we get the radius of the region of space occupied by the proton:

For a proton, this will be 4.5616 ∙ 10 -16 m. Thus, the outer boundary of the proton is located at a distance of 4.5616 ∙ 10 -16 m from the center of the particle. A small part of the mass concentrated in the constant electric and constant magnetic field of the proton, in accordance with the laws of electrodynamics, is outside this radius.

5 Magnetic moment of the proton

In contrast to quantum theory, the field theory of elementary particles states that the magnetic fields of elementary particles are not created by the spin rotation of electric charges, but exist simultaneously with a constant electric field as a constant component of the electromagnetic field. So all elementary particles with quantum number L>0 have constant magnetic fields.
The field theory of elementary particles does not consider the magnetic moment of the proton to be anomalous - its value is determined by a set of quantum numbers to the extent that quantum mechanics works in an elementary particle.
So the main magnetic moment of the proton is created by two currents:

• (+) with magnetic moment +2 (eħ/m 0 s)
• (-) with magnetic moment -0.5 (eħ/m 0 s)

To obtain the resulting magnetic moment of the proton, one must add both moments, multiply by the percentage of energy contained in the wave alternating electromagnetic field of the proton (divided by 100%) and add the spin component (see Field Theory of Elementary Particles, Part 2, Section 3.2), as a result we get 1.3964237 eh/m 0p c. In order to convert to conventional nuclear magnetons, the resulting number must be multiplied by two - as a result, we have 2.7928474.

When physics assumed that the magnetic moments of elementary particles are created by the spin rotation of their electric charge, appropriate units were proposed for their measurement: for a proton, this is eh / 2m 0p c (recall that the value of the proton spin is 1/2) called the nuclear magneton. Now 1/2 could be omitted, as not carrying a semantic load, and left simply eh / m 0p c.

But seriously, there are no electric currents inside elementary particles, but there are magnetic fields (and there are no electric charges, but there are electric fields). It is impossible to replace the true magnetic fields of elementary particles with the magnetic fields of currents (as well as the true electric fields of elementary particles with the fields of electric charges), without loss of accuracy - these fields have a different nature. Here is some other electrodynamics - the Electrodynamics of the Field Physics, which has yet to be created, like the Field Physics itself.

6 Proton electric field

6.1 Electric field of a proton in the far zone

Physics knowledge about structure electric field protons have changed as physics has evolved. Initially, it was believed that the electric field of the proton is the field of a point electric charge +e. For this field will be:
potential the electric field of the proton at the point (A) in the far zone (r > > r p) exactly, in the SI system is:

tension E of the electric field of the proton in the far zone (r > > r p) exactly, in the SI system is:

where n = r/|r| - unit vector from the center of the proton in the direction of the observation point (A), r - distance from the center of the proton to the observation point, e - elementary electric charge, vectors are in bold type, ε 0 - electrical constant, rp =Lħ/(m 0~ c ) is the radius of the proton in the field theory, L is the main quantum number of the proton in the field theory, ħ is Planck's constant, m 0~ - the value of the mass of a proton at rest in an alternating electromagnetic field, C - the speed of light. (There is no SI multiplier in the CGS system.)

These mathematical expressions are correct for the far zone of the proton electric field: r p , but physics then assumed that their validity extends to the near zone, up to distances of the order of 10 -14 cm.

6.2 Electric charges of the proton

In the first half of the 20th century, physics believed that the proton has only one electric charge and it is equal to +e.

After the appearance of the quark hypothesis, physics suggested that inside the proton there are not one, but three electric charges: two electric charges +2e/3 and one electric charge -e/3. These charges add up to +e. This was done because physics suggested that the proton has a complex structure and consists of two u-quarks with a charge of +2e/3 and one d-quark with a charge of -e/3. But quarks were not found either in nature or on accelerators at any energy, and it remained either to accept their existence on faith (which the supporters of the Standard Model did), or to look for another structure of elementary particles. But along with this, experimental information about elementary particles was constantly accumulating in physics, and when it accumulated enough to rethink what had been done, the field theory of elementary particles was born.

According to the field theory of elementary particles, a constant electric field of elementary particles with a quantum number L>0, both charged and neutral, is created by a constant component of the electromagnetic field of the corresponding elementary particle(not the electric charge is the root cause of the electric field, as physics believed in the 19th century, but the electric fields of elementary particles are such that they correspond to the fields of electric charges). And the field of electric charge arises as a result of the presence of asymmetry between the outer and inner hemispheres, generating electric fields of opposite signs. For charged elementary particles in the far zone, an elementary electric charge field is generated, and the sign of the electric charge is determined by the sign of the electric field generated by the outer hemisphere. In the near zone, this field has a complex structure and is a dipole, but it does not have a dipole moment. For an approximate description of this field as a system of point charges, at least 6 "quarks" inside the proton will be required - it will be more accurate if we take 8 "quarks". It is clear that the electric charges of such "quarks" will be completely different than the standard model (with its own quarks) believes.

The field theory of elementary particles has established that the proton, like any other positively charged elementary particle, can be distinguished two electric charges and respectively two electric radii:

• electric radius of external constant electric field (charge q + = +1.25e) - r q+ = 4.39 10 -14 cm,
• electric radius of the internal constant electric field (charge q - = -0.25e) - r q- = 2.45 10 -14 cm.

These characteristics of the electric field of the proton correspond to the distribution 1 of the field theory of elementary particles. Physics has not yet experimentally established the accuracy of this distribution and which distribution most accurately corresponds to the real structure of the proton's constant electric field in the near zone, as well as the very structure of the proton electric field in the near zone (at distances of the order of r p). As you can see, electric charges are close in magnitude to the charges of the alleged quarks (+4/3e=+1.333e and -1/3e=-0.333e) in the proton, but unlike quarks, electromagnetic fields exist in nature, and a similar structure of the constant any positively charged elementary particle has an electric field, regardless of the size of the spin and... .

The values ​​of electric radii for each elementary particle are unique and are determined by the main quantum number in the field theory L, the value of the rest mass, the percentage of energy contained in an alternating electromagnetic field (where quantum mechanics works) and the structure of the constant component of the electromagnetic field of an elementary particle (the same for all elementary particles with given principal quantum number L), which generates an external constant electric field. The electric radius indicates the average location of an electric charge evenly distributed around the circumference, which creates a similar electric field. Both electric charges lie in the same plane (the plane of rotation of the variable electromagnetic field of the elementary particle) and have a common center coinciding with the center of rotation of the variable electromagnetic field of the elementary particle.

6.3 Electric field of a proton in the near field

Knowing the magnitude of electric charges inside an elementary particle and their location, it is possible to determine the electric field created by them.

electric field of a proton in the near zone (r~r p), in the SI system, as a vector sum, is approximately equal to:

Where n+ = r+/|r + | - unit vector from the near (1) or far (2) proton charge point q + in the direction of the observation point (A), n- = r-/|r - | - unit vector from the near (1) or far (2) point of the proton charge q - in the direction of the observation point (А), r - distance from the center of the proton to the projection of the observation point onto the proton plane, q + - external electric charge +1.25e, q - - internal electric charge -0.25e, vectors are in bold type, ε 0 - electrical constant, z - height of the observation point (A) (distance from the observation point to the proton plane), r 0 - normalization parameter. (There is no SI multiplier in the CGS system.)

This mathematical expression is the sum of vectors and it must be calculated according to the rules of vector addition, since this is a field of two distributed electric charges (+1.25e and -0.25e). The first and third terms correspond to the near points of the charges, the second and fourth - to the far ones. This mathematical expression does not work in the inner (ring) region of the proton, which generates its constant fields (if two conditions are met simultaneously: ħ/m 0~ c
Electric field potential proton at point (A) in the near zone (r ~ r p), in the SI system is approximately equal to:

Where r 0 is a normalization parameter, the value of which may differ from r 0 in the formula E. (There is no multiplier in the CGS system Multiplier SI .) This mathematical expression does not work in the inner (ring) region of the proton, which generates its constant fields (with the simultaneous execution of two conditions: ħ/m 0~ s
Calibration of r 0 for both expressions of the near zone must be performed at the boundary of the region generating constant proton fields.

7 Proton rest mass

In accordance with classical electrodynamics and Einstein's formula, the rest mass of elementary particles with quantum number L>0, including the proton, is defined as the energy equivalent of their electromagnetic fields:

where the definite integral is taken over the entire electromagnetic field of the elementary particle, E is the electric field strength, H is the magnetic field strength. Here all components of the electromagnetic field are taken into account: a constant electric field, a constant magnetic field, an alternating electromagnetic field. This small, but very capacious formula for physics, on the basis of which the equations of the gravitational field of elementary particles are obtained, will send to the scrap more than one fabulous "theory" - therefore, some of their authors will hate it.

As follows from the above formula, the value of the rest mass of the proton depends on the conditions in which the proton is. So by placing a proton in a constant external electric field (for example, an atomic nucleus), we will affect E 2, which will affect the mass of the proton and its stability. A similar situation will arise when a proton is placed in a constant magnetic field. Therefore, some properties of the proton inside the atomic nucleus differ from the same properties of a free proton in vacuum, far from the fields.

8 Proton lifetime

The lifetime of a proton established by physics corresponds to a free proton.

The field theory of elementary particles states that the lifetime of an elementary particle depends on the conditions in which it is located. By placing a proton in an external field (for example, an electric one), we change the energy contained in its electromagnetic field. You can choose the sign of the external field so that the internal energy of the proton increases. You can choose such a value of the external field strength that it will become possible for the proton to decay into a neutron, a positron and an electron neutrino, and therefore the proton will become unstable. This is exactly what is observed in atomic nuclei, in them the electric field of neighboring protons triggers the decay of the proton of the nucleus. When additional energy is introduced into the nucleus, proton decays can begin at a lower external field strength.

One interesting feature: during the decay of a proton in an atomic nucleus, in the electromagnetic field of the nucleus, a positron is born from the energy of the electromagnetic field - from "substance" (proton) "antimatter" (positron) is born!!! and this surprises no one.

9 The truth about the Standard Model

And now let's get acquainted with the information that the supporters of the Standard Model will not allow to be published on "politically correct" sites (such as the world's Wikipedia) on which the opponents of New Physics can ruthlessly delete (or distort) the information of the supporters of New Physics, as a result of which the TRUTH fell a victim of politics

In 1964, Gellmann and Zweig independently proposed the hypothesis of the existence of quarks, of which, in their opinion, hadrons are composed. The new particles were endowed with a fractional electric charge that does not exist in nature.
Leptons did not fit into this Quark model, which later developed into the Standard Model, and therefore were recognized as true elementary particles.
To explain the connection of quarks in the hadron, the existence of a strong interaction in nature and its carriers, gluons, was assumed. Gluons, as it should be in the Quantum theory, endowed with a unit spin, the identities of a particle and an antiparticle and a zero value of the rest mass, like a photon.
In fact, in nature there is not a strong interaction of hypothetical quarks, but the nuclear forces of nucleons - and these are different concepts.

50 years have passed. Quarks were never found in nature, and a new mathematical fairy tale called "Confinement" was invented for us. A thinking person can easily see in it a frank disregard for the fundamental law of nature - the law of conservation of energy. But a thinking person will do this, and the storytellers received an excuse that suited them.

Gluons have also NOT been found in nature. The fact is that in nature only vector mesons (and one more of the excited states of mesons) can have a unit spin, but each vector meson has an antiparticle. - So vector mesons are in no way suitable for candidates for "gluons". The nine first excited states of mesons remain, but 2 of them contradict the Standard Model itself and the Standard Model does not recognize their existence in nature, and the rest are well studied by physics, and it will not work to pass them off as fabulous gluons. There is also the last option: to pass off a bound state from a pair of leptons (muons or tau-leptons) as a gluon - but this can also be calculated during decay.

So that, there are no gluons in nature either, just as there are no quarks and fictional strong interaction in nature.
You think that the supporters of the Standard Model do not understand this - they still understand, but it's just sickening to admit the fallacy of what he has been doing for decades. Therefore, we see new mathematical fairy tales ("theory" of strings, etc.).

10 New Physics: Proton - summary

In the main part of the article, I did not talk in detail about fairy quarks (with fairy gluons), since they are NOT in nature and there is nothing to bother with fairy tales (unnecessarily) - and without the fundamental elements of the foundation: quarks with gluons, the standard model collapsed - the time of its dominance in physics is ENDED (see Standard Model).

You can ignore the place of electromagnetism in nature for as long as you like (meeting it at every step: light, thermal radiation, electricity, television, radio, telephone communications, including cellular, the Internet, without which humanity would not have known about the existence of the Field Theory elementary particles, ...), and continue to compose new fairy tales to replace the bankrupt ones, passing them off as science; one can, with a tenacity worthy of a better application, continue to repeat the memorized FAIRY TALES of the Standard Model and Quantum Theory; but electromagnetic fields in nature were, are, will be and do fine without fabulous virtual particles, however, as well as gravity created by electromagnetic fields, but fairy tales have a time of birth and a time when they cease to influence people. As for nature, she does NOT care about fairy tales, and any other literary activity man, even if they are awarded the Nobel Prize in physics. Nature is arranged the way it is arranged, and the task of PHYSICS-SCIENCE is to understand and describe it.

Now opened before you new world- the world of dipole fields, the existence of which the physics of the 20th century did not suspect. You have seen that the proton has not one, but two electric charges (external and internal) and their corresponding two electric radii. You have seen what makes up the rest mass of the proton and that the imaginary Higgs boson was out of work (the decisions of the Nobel Committee are not yet the laws of nature...). Moreover, the magnitude of the mass and lifetime depend on the fields in which the proton is located. From the fact that a free proton is stable, it does not yet follow that it will remain stable always and everywhere (proton decays are observed in atomic nuclei). All this goes beyond the concepts that dominated physics in the second half of the twentieth century. - Physics of the 21st century - New physics moves to new level knowledge of matter, and we are waiting for new interesting discoveries.

Vladimir Gorunovich

DEFINITION

Proton called a stable particle belonging to the class of hadrons, which is the nucleus of a hydrogen atom.

Scientists disagree on what scientific events should be considered the discovery of the proton. An important role in the discovery of the proton was played by:

1. creation by E. Rutherford planetary model atom;
2. discovery of isotopes by F. Soddy, J. Thomson, F. Aston;
3. observations of the behavior of the nuclei of hydrogen atoms when they are knocked out by alpha particles from nitrogen nuclei by E. Rutherford.

The first photographs of proton traces were obtained by P. Blackett in a cloud chamber while studying the processes of artificial transformation of elements. Blackett investigated the capture of alpha particles by nitrogen nuclei. In this process, a proton was emitted and the nitrogen nucleus was converted into an oxygen isotope.

Protons, together with neutrons, are part of the nuclei of all chemical elements. The number of protons in the nucleus determines the atomic number of the element in periodic system DI. Mendeleev.

A proton is a positively charged particle. Its charge is equal in modulus to the elementary charge, that is, the magnitude of the charge of the electron. The charge of a proton is often denoted as , then we can write that:

At present, it is believed that the proton is not an elementary particle. It has a complex structure and consists of two u-quarks and one d-quark. The electric charge of the u - quark () is positive and it is equal to

The electric charge of the d - quark () is negative and equal to:

Quarks bind the exchange of gluons, which are field quanta, they carry the strong interaction. The fact that protons have several point scattering centers in their structure is confirmed by experiments on the scattering of electrons by protons.

The proton has a finite size, which scientists are still arguing about. At present, the proton is represented as a cloud that has blurred border. Such a boundary consists of constantly emerging and annihilating virtual particles. But in most simple tasks proton, of course, can be considered point charge. The rest mass of a proton () is approximately equal to:

The mass of a proton is 1836 times greater than the mass of an electron.

Protons take part in all fundamental interactions: strong interactions unite protons and neutrons into nuclei, electrons and protons combine in atoms with the help of electromagnetic interactions. We can cite, for example, the beta decay of a neutron (n) as a weak interaction:

where p is a proton; - electron; - antineutrino.

The decay of the proton has not yet been obtained. This is one of the important modern tasks physics, since this discovery would be a significant step in understanding the unity of the forces of nature.

Examples of problem solving

EXAMPLE 1

Exercise	The nuclei of the sodium atom are bombarded with protons. What is the electrostatic repulsion force of a proton from the nucleus of an atom if the proton is at a distance m. Consider that the charge of the nucleus of the sodium atom is 11 times greater than the charge of the proton. Influence electron shell the sodium atom can be omitted.
Solution	We will take Coulomb's law as the basis for solving the problem, which can be written for our problem (assuming particles are point particles) as follows: where F is the force of electrostatic interaction of charged particles; Cl is the proton charge; - the charge of the nucleus of the sodium atom; - vacuum permittivity; is the electrical constant. Using the data we have, we can calculate the desired repulsive force:
Answer	H

EXAMPLE 2

Exercise

Considering the simplest model of the hydrogen atom, it is believed that the electron moves in a circular orbit around the proton (the nucleus of the hydrogen atom). What is the speed of the electron if the radius of its orbit is m?

Solution

Consider the forces (Fig. 1) that act on an electron moving in a circle. This is the force of attraction from the side of the proton. According to Coulomb's law, we write that its value is equal to (): where = is the electron charge; - proton charge; is the electrical constant. The force of attraction between an electron and a proton at any point of the electron's orbit is directed from the electron to the proton along the radius of the circle.