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FUNDAMENTAL TRUTH

FUNDAMENTAL TRUTH In our parable, Jalin is a type of Jesus Christ, but is the king the Father? it is Almighty God the Father. Dagon represents! the devil; life in Endel? it is human life on earth; Affabel represents the heavenly city of God. Forsaken land Lon?

These three particles (as well as others described below) mutually attract and repel each other according to their charges, which are only four types according to the number of fundamental forces of nature. Charges can be arranged in order of decreasing corresponding forces as follows: color charge (forces of interaction between quarks); electric charge (electric and magnetic forces); weak charge (strength in some radioactive processes); finally, mass (gravitational force, or gravitational interaction). The word "color" here has nothing to do with the color of visible light; it is simply a characteristic of the strongest charge and the greatest forces.

Charges persist, i.e. The charge entering the system is equal to the charge leaving it. If the total electric charge of a certain number of particles before their interaction is, say, 342 units, then after the interaction, regardless of its result, it will be equal to 342 units. This also applies to other charges: color (strong interaction charge), weak and mass (mass). Particles differ in their charges: in essence, they "are" these charges. Charges are, as it were, a “certificate” of the right to respond to the corresponding force. Thus, only colored particles are affected by color forces, only electrically charged particles are affected by electric forces, and so on. The properties of a particle are determined by the greatest force acting on it. Only quarks are carriers of all charges and, therefore, are subject to the action of all forces, among which color is dominant. Electrons have all charges except color, and the dominant force for them is the electromagnetic force.

The most stable in nature are, as a rule, neutral combinations of particles in which the charge of particles of one sign is compensated by the total charge of particles of another sign. This corresponds to the minimum energy of the entire system. (Similarly, two bar magnets are in a line, with the north pole of one facing the south pole of the other, which corresponds to a minimum of magnetic field energy.) Gravity is an exception to this rule: negative mass does not exist. There are no bodies that would fall up.

TYPES OF MATTER

Ordinary matter is formed from electrons and quarks, grouped into objects that are neutral in color, and then in electric charge. The color force is neutralized, which will be discussed in more detail below, when the particles are combined into triplets. (Hence the term “color” itself, taken from optics: the three primary colors, when mixed, give white.) Thus, quarks, for which the color power is dominant, form triplets. But quarks, and they are subdivided into u-quarks (from English up - upper) and d-quarks (from the English down - lower), they also have an electric charge equal to u-quark and for d-quark. Two u-quark and one d-quark give an electric charge +1 and form a proton, and one u-quark and two d-quarks give zero electric charge and form a neutron.

Stable protons and neutrons, attracted to each other by the residual color forces of interaction between their constituent quarks, form a color-neutral atomic nucleus. But the nuclei carry a positive electric charge and, by attracting negative electrons that revolve around the nucleus like planets revolving around the Sun, tend to form a neutral atom. Electrons in their orbits are removed from the nucleus by distances tens of thousands of times greater than the radius of the nucleus - evidence that the electrical forces holding them are much weaker than nuclear ones. Due to the power of color interaction, 99.945% of the mass of an atom is enclosed in its nucleus. Weight u- and d-quarks are about 600 times the mass of an electron. Therefore, electrons are much lighter and more mobile than nuclei. Their movement in matter causes electrical phenomena.

There are several hundred natural varieties of atoms (including isotopes) that differ in the number of neutrons and protons in the nucleus and, accordingly, in the number of electrons in orbits. The simplest is the hydrogen atom, consisting of a nucleus in the form of a proton and a single electron revolving around it. All "visible" matter in nature consists of atoms and partially "disassembled" atoms, which are called ions. Ions are atoms that, having lost (or gained) a few electrons, have become charged particles. Matter, consisting almost of one ions, is called plasma. Stars that burn due to thermonuclear reactions going on in the centers are composed mainly of plasma, and since stars are the most common form of matter in the universe, it can be said that the entire universe consists mainly of plasma. More precisely, stars are predominantly fully ionized gaseous hydrogen, i.e. a mixture of individual protons and electrons, and therefore almost the entire visible universe consists of it.

This is visible matter. But there is still invisible matter in the Universe. And there are particles that act as carriers of forces. There are antiparticles and excited states of some particles. All this leads to a clearly excessive abundance of "elementary" particles. In this abundance, one can find an indication of the real, true nature of elementary particles and the forces acting between them. According to the most recent theories, particles can basically be extended geometric objects - "strings" in ten-dimensional space.

Invisible world.

There is not only visible matter in the universe (but also black holes and "dark matter" such as cold planets that become visible when illuminated). There is also a truly invisible matter that permeates all of us and the entire Universe every second. It is a fast-moving gas of one kind of particles - electron neutrinos.

The electron neutrino is the partner of the electron, but has no electric charge. Neutrinos carry only the so-called weak charge. Their rest mass is, in all likelihood, zero. But they interact with the gravitational field, because they have kinetic energy E, which corresponds to the effective mass m, according to the Einstein formula E = mc 2 , where c is the speed of light.

The key role of the neutrino is that it contributes to the transformation and-quarks in d quarks, resulting in the transformation of a proton into a neutron. The neutrino plays the role of the "carburetor needle" for stellar thermonuclear reactions, in which four protons (hydrogen nuclei) combine to form a helium nucleus. But since the helium nucleus consists not of four protons, but of two protons and two neutrons, for such nuclear fusion it is necessary that two and-quarks turned into two d-quark. The intensity of the transformation determines how fast the stars will burn. And the transformation process is determined by weak charges and forces of weak interaction between particles. Wherein and-quark (electric charge +2/3, weak charge +1/2), interacting with an electron (electric charge - 1, weak charge -1/2), forms d-quark (electric charge -1/3, weak charge -1/2) and electron neutrino (electric charge 0, weak charge +1/2). The color charges (or simply colors) of the two quarks cancel out in this process without the neutrino. The role of the neutrino is to carry away the uncompensated weak charge. Therefore, the rate of transformation depends on how weak the weak forces are. If they were weaker than they are, then the stars would not burn at all. If they were stronger, then the stars would have burned out long ago.

But what about neutrinos? Since these particles interact extremely weakly with other matter, they almost immediately leave the stars in which they were born. All stars shine, emitting neutrinos, and neutrinos shine through our bodies and the entire Earth day and night. So they wander through the Universe, until they enter, perhaps, into a new interaction of the STAR) .

Interaction carriers.

What causes forces that act between particles at a distance? Modern physics answers: due to the exchange of other particles. Imagine two skaters tossing a ball around. Giving the ball momentum when throwing and receiving momentum with the received ball, both get a push in the direction from each other. This can explain the emergence of repulsive forces. But in quantum mechanics, which considers phenomena in the microworld, unusual stretching and delocalization of events are allowed, which leads, it would seem, to the impossible: one of the skaters throws the ball in the direction from the other, but the one nonetheless maybe catch this ball. It is not difficult to imagine that if this were possible (and in the world of elementary particles it is possible), there would be attraction between the skaters.

Particles, due to the exchange of which interaction forces arise between the four “particles of matter” discussed above, are called gauge particles. Each of the four interactions - strong, electromagnetic, weak and gravitational - has its own set of gauge particles. The strong interaction carrier particles are gluons (there are only eight of them). A photon is a carrier of electromagnetic interaction (it is one, and we perceive photons as light). The particles-carriers of the weak interaction are intermediate vector bosons (in 1983 and 1984 were discovered W + -, W- -bosons and neutral Z-boson). The particle-carrier of the gravitational interaction is still a hypothetical graviton (it must be one). All these particles, except for the photon and graviton, which can travel infinitely long distances, exist only in the process of exchange between material particles. Photons fill the Universe with light, and gravitons - with gravitational waves (not yet detected with certainty).

A particle capable of emitting gauge particles is said to be surrounded by an appropriate force field. Thus, electrons capable of emitting photons are surrounded by electric and magnetic fields, as well as weak and gravitational fields. Quarks are also surrounded by all these fields, but also by the field of strong interaction. Particles with a color charge in the field of color forces are affected by the color force. The same applies to other forces of nature. Therefore, we can say that the world consists of matter (material particles) and field (gauge particles). More on this below.

Antimatter.

Each particle corresponds to an antiparticle, with which the particle can mutually annihilate, i.e. "annihilate", as a result of which energy is released. "Pure" energy by itself, however, does not exist; as a result of annihilation, new particles (for example, photons) appear, carrying away this energy.

An antiparticle in most cases has the opposite properties with respect to the corresponding particle: if a particle moves to the left under the action of strong, weak or electromagnetic fields, then its antiparticle will move to the right. In short, the antiparticle has opposite signs of all charges (except the mass charge). If a particle is composite, like, for example, a neutron, then its antiparticle consists of components with opposite charge signs. Thus, an antielectron has an electric charge of +1, a weak charge of +1/2 and is called a positron. The antineutron is made up of and-antiquarks with electric charge –2/3 and d-antiquarks with electric charge +1/3. Truly neutral particles are their own antiparticles: the photon's antiparticle is the photon.

According to modern theoretical concepts, each particle that exists in nature must have its own antiparticle. And many antiparticles, including positrons and antineutrons, were indeed obtained in the laboratory. The consequences of this are exceptionally important and underlie the entire experimental physics of elementary particles. According to the theory of relativity, mass and energy are equivalent, and under certain conditions, energy can be converted into mass. Since charge is conserved and the charge of vacuum (empty space) is zero, any pair of particles and antiparticles (with zero net charge) can emerge from vacuum, like rabbits from a magician's hat, as long as the energy is sufficient to create their mass.

Generations of particles.

Accelerator experiments have shown that the quadruple (quartet) of material particles is repeated at least twice at higher mass values. In the second generation, the place of the electron is occupied by the muon (with a mass about 200 times greater than the mass of the electron, but with the same values ​​of all other charges), the place of the electron neutrino is the muon (which accompanies the muon in weak interactions in the same way that the electron accompanies the electron neutrino), place and-quark occupies With-quark ( charmed), a d-quark - s-quark ( strange). In the third generation, the quartet consists of a tau lepton, a tau neutrino, t-quark and b-quark.

Weight t-quark is about 500 times the mass of the lightest one - d-quark. It has been experimentally established that there are only three types of light neutrinos. Thus, the fourth generation of particles either does not exist at all, or the corresponding neutrinos are very heavy. This is consistent with cosmological data, according to which there can be no more than four types of light neutrinos.

In experiments with high-energy particles, the electron, muon, tau-lepton and the corresponding neutrinos act as separate particles. They do not carry a color charge and only enter into weak and electromagnetic interactions. Collectively they are called leptons.

Quarks, on the other hand, under the influence of color forces, combine into strongly interacting particles that dominate most experiments in high-energy physics. Such particles are called hadrons. They include two subclasses: baryons(e.g. proton and neutron), which are made up of three quarks, and mesons consisting of a quark and an antiquark. In 1947, the first meson, called the pion (or pi-meson), was discovered in cosmic rays, and for some time it was believed that the exchange of these particles was the main cause of nuclear forces. The omega-minus hadrons, discovered in 1964 at the Brookhaven National Laboratory (USA), and the j-psy particle ( J/y-meson), discovered simultaneously in Brookhaven and at the Stanford Center for Linear Accelerators (also in the USA) in 1974. The existence of the omega-minus particle was predicted by M. Gell-Mann in his so-called " SU 3-theory” (another name is the “eight-fold way”), in which the possibility of the existence of quarks was first suggested (and this name was given to them). A decade later, the discovery of the particle J/y confirmed the existence With-quark and finally made everyone believe in both the quark model and the theory that combined electromagnetic and weak forces ( see below).

Particles of the second and third generations are no less real than those of the first. True, having arisen, they decay in millionths or billionths of a second into ordinary particles of the first generation: an electron, an electron neutrino, and also and- and d-quarks. The question of why there are several generations of particles in nature is still a mystery.

Different generations of quarks and leptons are often spoken of (which is, of course, somewhat eccentric) as different "flavors" of particles. The need to explain them is called the "flavor" problem.

BOSONS AND FERMIONS, FIELD AND SUBSTANCE

One of the fundamental differences between particles is the difference between bosons and fermions. All particles are divided into these two main classes. Like bosons can overlap or overlap, but like fermions can't. Superposition occurs (or does not occur) in the discrete energy states into which quantum mechanics divides nature. These states are, as it were, separate cells into which particles can be placed. So, in one cell you can put any number of identical bosons, but only one fermion.

As an example, consider such cells, or "states", for an electron revolving around the nucleus of an atom. Unlike the planets of the solar system, according to the laws of quantum mechanics, an electron cannot circulate in any elliptical orbit, for it there is only a discrete number of allowed "states of motion". Sets of such states, grouped according to the distance from the electron to the nucleus, are called orbitals. In the first orbital, there are two states with different angular momenta and, therefore, two allowed cells, and in higher orbitals, eight or more cells.

Since an electron is a fermion, each cell can contain only one electron. From this follow very important consequences - the whole of chemistry, since the chemical properties of substances are determined by the interactions between the corresponding atoms. If you go through the periodic system of elements from one atom to another in order of increasing by unit the number of protons in the nucleus (the number of electrons will also increase accordingly), then the first two electrons will occupy the first orbital, the next eight will be located in the second, etc. This successive change in the electronic structure of atoms from element to element determines the regularities in their chemical properties.

If the electrons were bosons, then all the electrons of an atom could occupy the same orbital corresponding to the minimum energy. In this case, the properties of all matter in the Universe would be completely different, and in the form in which we know it, the Universe would be impossible.

All leptons - electron, muon, tau-lepton and their corresponding neutrino - are fermions. The same can be said about quarks. Thus, all particles that form "matter", the main filler of the Universe, as well as invisible neutrinos, are fermions. This is very significant: fermions cannot combine, so the same applies to objects in the material world.

At the same time, all "gauge particles" exchanged between interacting material particles and which create a field of forces ( see above), are bosons, which is also very important. So, for example, many photons can be in the same state, forming a magnetic field around a magnet or an electric field around an electric charge. Thanks to this, a laser is also possible.

Spin.

The difference between bosons and fermions is connected with another characteristic of elementary particles - back. Surprising as it may seem, but all fundamental particles have their own angular momentum or, in other words, rotate around their own axis. The angular momentum is a characteristic of rotational motion, just like the total momentum is of translational motion. In any interaction, angular momentum and momentum are conserved.

In the microcosm, the angular momentum is quantized, i.e. takes discrete values. In suitable units, leptons and quarks have a spin of 1/2, and gauge particles have a spin of 1 (except for the graviton, which has not yet been observed experimentally, but theoretically should have a spin of 2). Since leptons and quarks are fermions, and gauge particles are bosons, it can be assumed that "fermionicity" is associated with spin 1/2, and "bosonicity" is associated with spin 1 (or 2). Indeed, both experiment and theory confirm that if a particle has a half-integer spin, then it is a fermion, and if it is integer, then it is a boson.

GAUGE THEORIES AND GEOMETRY

In all cases, the forces arise due to the exchange of bosons between fermions. Thus, the color force of interaction between two quarks (quarks - fermions) arises due to the exchange of gluons. Such an exchange constantly takes place in protons, neutrons and atomic nuclei. In the same way, photons exchanged between electrons and quarks create electrical attractive forces that hold electrons in an atom, and intermediate vector bosons exchanged between leptons and quarks create weak interaction forces responsible for the conversion of protons into neutrons in fusion reactions in stars.

The theory of such an exchange is elegant, simple, and probably correct. It is called gauge theory. But at present there are only independent gauge theories of strong, weak and electromagnetic interactions and a gauge theory of gravity similar to them, although in some ways different. One of the most important physical problems is the reduction of these separate theories into a single and at the same time simple theory, in which all of them would become different aspects of a single reality - like the facets of a crystal.

The simplest and oldest of gauge theories is the gauge theory of electromagnetic interaction. In it, the charge of an electron is compared (calibrated) with the charge of another electron distant from it. How can charges be compared? You can, for example, bring the second electron closer to the first and compare their interaction forces. But doesn't the charge of an electron change when it moves to another point in space? The only way to check is to send a signal from the near electron to the far one and see how it reacts. The signal is a gauge particle - a photon. In order to be able to check the charge on distant particles, a photon is needed.

Mathematically, this theory is distinguished by extreme precision and beauty. From the "gauge principle" described above, all quantum electrodynamics (the quantum theory of electromagnetism) follows, as well as Maxwell's theory of the electromagnetic field, one of the greatest scientific achievements of the 19th century.

Why is such a simple principle so fruitful? Apparently, it expresses a certain correlation of different parts of the Universe, allowing measurements in the Universe. In mathematical terms, the field is interpreted geometrically as the curvature of some conceivable "internal" space. The measurement of charge is the measurement of the total "internal curvature" around the particle. The gauge theories of strong and weak interactions differ from the electromagnetic gauge theory only in the internal geometric "structure" of the corresponding charge. The question of where exactly this inner space is located is being answered by multidimensional unified field theories, which are not considered here.

The physics of elementary particles is not completed yet. It is still far from clear whether the available data are sufficient to fully understand the nature of particles and forces, as well as the true nature and dimensions of space and time. Do we need experiments with energies of 10 15 GeV for this, or will the effort of thought be enough? There is no answer yet. But we can say with confidence that the final picture will be simple, elegant and beautiful. It is possible that there will be not so many fundamental ideas: the gauge principle, spaces of higher dimensions, collapse and expansion, and, above all, geometry.

Until relatively recently, several hundred particles and antiparticles were considered elementary. A detailed study of their properties and interactions with other particles and the development of the theory showed that most of them are in fact not elementary, since they themselves consist of the simplest or, as they say now, fundamental particles. Fundamental particles themselves no longer consist of anything. Numerous experiments have shown that all fundamental particles behave like dimensionless point objects with no internal structure, at least up to the smallest distances currently studied ~10 -16 cm.

Among the countless and varied processes of interaction between particles, there are four basic or fundamental interactions: strong (nuclear), electromagnetic, weak and gravitational . In the world of particles, the gravitational interaction is very weak, its role is still unclear, and we will not talk about it further.

In nature, there are two groups of particles: hadrons, which participate in all fundamental interactions, and leptons, which do not participate only in the strong interaction.

According to modern concepts, interactions between particles are carried out through the emission and subsequent absorption of quanta of the corresponding field (strong, weak, electromagnetic) surrounding the particle. These quanta are gauge bosons, which are also fundamental particles. Bosons have their own moment of momentum, called the spin, is equal to the integer value Planck's constant. The quanta of the field and, accordingly, the carriers of the strong interaction are gluons, denoted by the symbol g (ji), the quanta of the electromagnetic field are the well-known quanta of light - photons, denoted by (gamma), and the quanta of the weak field and, accordingly, the carriers of weak interactions are W± (double ve) - and Z 0 (zet zero)-bosons.

Unlike bosons, all other fundamental particles are fermions, that is, particles that have a half-integer spin equal to h/2.

In table. 1 shows the symbols of fundamental fermions - leptons and quarks.

Each particle given in table. 1 corresponds to an antiparticle, which differs from a particle only in the signs of the electric charge and other quantum numbers (see Table 2) and in the direction of the spin relative to the direction of the particle's momentum. We will denote antiparticles with the same symbols as particles, but with a wavy line above the symbol.

Particles in the table. 1 are denoted by Greek and Latin letters, namely: the letter (nu) - three different neutrinos, the letters e - electron, (mu) - muon, (tau) - taon, the letters u, c, t, d, s, b denote quarks ; their names and characteristics are given in table. 2.

Particles in the table. 1 are grouped into three generations I, II and III according to the structure of modern theory. Our Universe is built of particles of the first generation - leptons and quarks and gauge bosons, but, as modern science of the development of the Universe shows, at the initial stage of its development particles of all three generations played an important role.

Leptons

Let us first consider the properties of leptons in more detail. In the top line of the table 1 contains three different neutrinos: electron, muon and tau neutrinos. Their mass has not yet been accurately measured, but its upper limit has been determined, for example, for ne equal to 10 -5 of the electron mass (that is, g).

Looking at Table. 1 involuntarily raises the question of why nature needed the creation of three different neutrinos. There is no answer to this question yet, because such a comprehensive theory of fundamental particles has not been created, which would indicate the necessity and sufficiency of all such particles and would describe their main properties. Perhaps this problem will be solved in the 21st century (or later).

The bottom line of the table. 1 begins with the particle we have studied the most - the electron. The electron was discovered at the end of the last century by the English physicist J. Thomson. The role of electrons in our world is enormous. They are those negatively charged particles that, together with atomic nuclei, form all the atoms of the elements known to us. Periodic table of Mendeleev. In each atom, the number of electrons is exactly equal to the number of protons in the atomic nucleus, which makes the atom electrically neutral.

The electron is stable, the main possibility of destroying an electron is its death in a collision with an antiparticle - a positron e + . This process has been named annihilation :

As a result of annihilation, two gamma quanta are formed (the so-called high-energy photons), which carry away both the rest energies e + and e - and their kinetic energies. At high energies e + and e - hadrons and quark pairs are formed (see, for example, (5) and Fig. 4).

Reaction (1) clearly illustrates the validity of A. Einstein's famous formula about the equivalence of mass and energy: E = mc 2 .

Indeed, during the annihilation of a positron stopped in a substance and an electron at rest, the entire mass of their rest (equal to 1.22 MeV) passes into the energy of quanta, which do not have a rest mass.

In the second generation of the bottom row of Table. 1 located muon- a particle that is analogous to an electron in all its properties, but with an anomalously large mass. The mass of the muon is 207 times the mass of the electron. Unlike the electron, the muon is unstable. The time of his life t= 2.2 10 -6 s. The muon mainly decays into an electron and two neutrinos according to the scheme

An even heavier analogue of the electron is . Its mass is more than 3 thousand times greater than the mass of an electron ( MeV / s 2), that is, the taon is heavier than the proton and neutron. Its lifetime is 2.9 · 10 -13 s, and out of more than a hundred different schemes (channels) of its decay, the following are possible.

see also

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• S. A. Slavatinsky// Moscow Institute of Physics and Technology (Dolgoprudny, Moscow region)
• Slavatinsky S.A. // SOZH, 2001, No 2, p. 62–68 archive http://web.archive.org/web/20060116134302/http://journal.issep.rssi.ru/annot.php?id=S1176
• // nuclphys.sinp.msu.ru
• // second-physics.ru
• // physics.ru
• // nature.web.ru
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Presented in Fig.1 fundamental fermions, with spin ½, are the "first bricks" of matter. They are represented leptons(electrons e, neutrino, etc.) - particles not participating in strong nuclear interactions, and quarks, which are involved in strong interactions. Nuclear particles are made up of quarks hadrons(protons, neutrons and mesons). Each of these particles has its own antiparticle, which must be placed in the same cell. The designation of an antiparticle is distinguished by the tilde sign (~).

Of the six varieties of quarks, or six fragrances electric charge 2/3 (in units of elementary charge e) possess upper ( u), charmed ( c) and true ( t) quarks, and with charge –1/3 – lower ( d), strange ( s) and beautiful ( b) quarks. Antiquarks with the same flavors will have electric charges of -2/3 and 1/3, respectively.

In quantum chromodynamics (the theory of the strong interaction), three types of strong interaction charges are attributed to quarks and antiquarks: red R(anti-red); green G(anti-green); blue B(anti blue). Color (strong) interaction binds quarks in hadrons. The latter are divided into baryons, consisting of three quarks, and mesons consisting of two quarks. For example, protons and neutrons related to baryons have the following quark composition:

p = (uud) and , n = (ddu) and .

As an example, we present the composition of the pi-meson triplet:

, ,

It is easy to see from these formulas that the charge of the proton is +1, while that of the antiproton is -1. Neutron and antineutron have zero charge. The spins of the quarks in these particles are added so that their total spins are equal to ½. Such combinations of the same quarks are also possible, in which the total spins are equal to 3/2. Such elementary particles (D ++ , D + , D 0 , D –) have been discovered and belong to resonances, i.e. short lived hadrons.

The known process of radioactive b-decay, which is represented by the scheme

n ® p + e + ,

from the point of view of quark theory looks like

(udd) ® ( uud) + e+ or d ® u + e + .

Despite repeated attempts to detect free quarks in experiments, it was not possible. This suggests that quarks, apparently, appear only in the composition of more complex particles ( trapping quarks). A complete explanation of this phenomenon has not yet been given.

Figure 1 shows that there is a symmetry between leptons and quarks, called quark-lepton symmetry. Particles in the top row have one more charge than particles in the bottom row. The particles of the first column belong to the first generation, the second - to the second generation, and the third column - to the third generation. Proper quarks c, b and t were predicted based on this symmetry. The matter surrounding us consists of particles of the first generation. What is the role of particles of the second and third generations? There is no definitive answer to this question yet.