Hadron detailed data collection

Hadron is a concept in modern particle physics and an important concept in quantum mechanics.

Hadron is a subatomic particle, and all subatomic particles affected by strong interaction are called hadrons. Hadron, including baryon and meson.

According to the standard model theory in modern particle physics, hadrons are composed of quarks, antiquarks and gluons. Gluon is the basic particle in quantum chromodynamics, which connects quarks together, and hadron is the product of these connections.

Chinese name: hadron mbth: hadron explanation: concept types of particle physics and quantum mechanics: subatomic particle classification, composition, straton model, related viewpoints and classification. According to different quarks, hadrons can also be divided into baryons: baryons are composed of three quarks or three antiquarks, and the spin is always half, that is, fermions. They include the familiar protons and neutrons that make up the nucleus, and the little-known hyperons (such as δ, λ, σ, ξ and ω), which are generally heavier than the nucleus and have a very short life. Mesons: Mesons consist of a quark and an antiquark. Their spins are integers, which means they are bosons. There are many kinds of mesons. Mesons are produced when high-altitude rays interact with the earth's air. Other rare and strange hadrons. A baryon-like hadron consists of more than three odd quarks or antiquarks. Meson-like hadrons composed of more than one quark-antiquark pair. Particles composed entirely of gluons. The spin of a meson (the inherent angular momentum of a particle) has an integer quantum number (also called a boson), and the spin quantum number of a baryon is a semi-integer. The spin quantum number of proton (also fermion) is half integer 1/2, which participates in strong interaction. So protons belong to a kind of hadron. All hadrons found so far satisfy the gherman-Nishi relation, that is, S=2(Q-I3)-B, s is odd, q is charge, I3 is isospin, and b is baryon number. The composition of hadron is one of the basic problems in particle physics. In the naive quark model, hadrons are composed of (mesons) and (baryons). But this simple structure is being seriously challenged by experiments. More and more unclassified hadron states and mesons have been discovered, whose quantum numbers are not allowed by naive quark model, which implies the existence of new hadrons outside naive quark model. Colloidal sphere, multi-quark state and hybridization are three possible new hadron structures, which are gluons, multi-quark and quark gluons. This paper will study the properties of these new hadrons. Firstly, the research methods adopted in this paper are introduced. Because we adopt the QCD summation rule as our main theoretical framework, we mainly adopt a semi-phenomenological method, that is, single instanton approximation, which is easy to use in the QCD summation rule framework of instanton physics. Study on the properties of some new hadrons. After considering the direct instanton effect, we study the mass of colloidal spheres under the framework of QCD summation rule. The results show that the mass of colloidal spheres is greatly reduced after considering the instanton effect. Then we consider the role of instanton effect in the decay of scalar colloidal spheres. We find that the symmetry is well maintained during the decay of scalar colloidal particles due to the non-perturbation effect. We also consider the ratio of the four quark decay width to the two quark decay width of scalar colloidal spheres. Compared with ordinary meson decay, we predict that scalar glueball decay will have a larger branching ratio of multi-hadron final States. Firstly, two typical molecular four-quark states are constructed, and their mass problems are studied by using the modified QCD summation rule considering instantaneous effect. We find that our model can accommodate two different kinds of four quark mesons around1.4gev. Then four quark states with double quark structure and molecular structure are constructed, and their decay modes are studied. In this paper, the direct instanton effect is considered in the existing mass summation rules of mixed particles, the role of instanton in it is studied, and the stable mass prediction of colloidal balls is given. 1964, American scientist gherman and others put forward the quark model. They think that all hadrons are made up of several deeper particles called quarks. Westerners call these particles quarks, while China people usually call them stratons. As the name implies, stratons belong to the "next level particles" relative to basic particles such as electrons, protons and neutrons. Gherman and others think quarks have "fractional charges", they are confined in hadrons, and they cannot move freely without them. Quarks are the limit of matter splitting, because quarks are confined in hadrons and cannot be directly observed. However, curiosity about nature aroused people's strong interest in whether quarks still have "internal structure". The current evidence shows that quarks and leptons may be composed of some more basic particles, and there is great symmetry between quarks and leptons. According to the current theory, quarks can be divided into three generations, and each generation has two kinds (excluding antiquarks), namely (U, D), (S, C) and (T, B). There are three generations of leptons, and each generation has two kinds. So many particles show that even quarks and leptons can't be the "smallest unit" of matter splitting. But since 1964, people have never "seen" quarks. In the quark theory put forward by gherman, he assumed that there were three kinds of quarks. He used these three quarks and their antiparticles to illustrate the model of microscopic particles and achieved great success. However, because physicists have not been able to make quarks exist independently of other microscopic particles, they can only be confined in microscopic particles like soldiers who have made mistakes. Therefore, "quark confinement" has become one of the difficult problems in particle physics today, which is also a severe challenge to the philosophical view that matter is infinitely separable. For nearly half a century, physicists have racked their brains to find free quarks. Whenever a new high-energy accelerator is built, one of the first tasks is to try to find quarks. Some physicists imagine microscopic particles as a pocket, and quarks are always wrapped in this pocket-within a small range of this pocket, it can fly freely, but it must never leave this pocket. It is this mysterious pocket that seems to isolate quarks from the outside world forever. Some physicists believe that the micro is a "well" with a small radius and a deep depth, and quarks live a life of "sitting in the well and watching the sky". In the "well", they are quite free and don't move fast, but they just can't get out. People must provide great energy to pull it out of the well. But at present, people have no way to generate so much energy to "liberate" quarks. Unable to find the free quark directly, some physicists changed their strategies and tried to find it indirectly. Because quarks have a so-called "fractional charge" according to theory, which gives physicists a glimmer of hope. They think that as long as the carrier of "fractional charge" is found, it may be the embodiment of quarks. As a result, physicists "weave webs" in particle accelerators, meteorites, the moon, underground deep wells, the seabed and many other places, looking for particles with "fractional charges" everywhere. At present, experiments to detect quark structure and lepton structure are going on, but there is no progress. Considering that the linear difference between atom and nucleus is 65438+ million times, it can be predicted that quark structure can only be displayed on the scale of 10-20 meters at most; However, the current experiment can only detect the linearity of 10-17 meters, so whether quarks have "internal structure" is still a mystery. The straton model of hadron structure was completed from September 1965 to June 1966. At that time, the research background was like this: after the discovery of electrons, protons and neutrons, people generally thought that they were the ultimate units of matter and called them "elementary particles". With the discovery of mesons and hyperons in the 1940s and 1950s, the family of elementary particles expanded rapidly. Most of these particles are strongly interacting particles, which are called hadrons for short. It is hard to imagine that so many hadrons are elementary particles. 1955, Japanese physicist Sakata proposed a structural model: only protons, neutrons and hyperons are basic particles in hadrons, which constitute all other hadrons. There are a series of difficulties in Sakata model, but the idea that hadron has internal structure is correct. 1964, gherman, an American physicist, reformed the Sakata model and put forward the "quark model". He thinks that hadron is composed of three components with SU(3) symmetry, which he calls quarks. By 1965, the number of particles in the basic particle table can be compared with the number of elements in the periodic table of elements, and the baryon spin can be as high as 1 1/2. The experimental measurement of the nuclear electromagnetic shape factor shows that the nuclei previously considered as basic particles have a certain size and spatial structure. These facts illustrate two points. One is that "elementary particles" are not basic, and the other is that hadrons have internal structures. Both Sakata model and quark model are scientific ideas about hadron structure, which need to be further developed into the scientific theory of hadron structure. However, it was difficult to develop the theory of hadron structure at that time, because we didn't know whether there were any new mechanical laws in hadron, the specific form of strong interaction and the mathematical method to deal with it, so we only discussed the static properties such as mass, spin, charge and magnetic moment that can be obtained from symmetry in hadron classification, new particle prediction and structural model. Further development must go beyond the category of symmetry and introduce dynamic factors. At the highest energy known at that time, the results of physical experiments show that the concepts of quantum number, eigenvalue and probability wave are still valid, that is to say, in the small scale of hadron, the basic concepts and methods of describing states with wave functions and describing physical quantities with operators are still valid. So he proposed to introduce the wave function of hadron internal structure to describe the state of hadron internal structure. As for the mechanical laws and equations of motion that determine the wave function, we will discuss them later. Some strict physical requirements, such as relativistic Lorentz covariance and internal symmetry, greatly limit the possible forms of wave function. Whether the composition of hadron and the symmetry it obeys adopt quark model or other variants of Sakata model, so later, according to Qian Sanqiang's suggestion, the constituent particles of hadron are called "stratons", which means one of many levels of material structure. When introducing wave function to describe moving hadrons, he thinks that the two concepts of describing internal motion and global motion should be distinguished. Through the analysis of the known experimental data, he proposed that the velocity of the inner layer of hadron is much less than the speed of light, which is non-relativistic, although the overall motion of hadron can be relativistic. In this way, the wave function of non-relativistic structure can be determined in the static coordinate system of hadron, and then the wave function of free-moving hadron can be obtained by Lorentz transformation. When discussing the hadron transformation process, Zhu Hongyuan introduced the concept of overlapping integral of the initial and final hadron structure wave functions and the interaction between hadron components (layers) with specific symmetry to calculate the transition matrix elements, thus uniformly describing a series of hadron transformation processes. On the basis of these concepts and methods, supported by Qian Sanqiang and led by Zhu Hongyuan, the particle theory research group systematically studied the static properties of hadron, such as mechanics, electromagnetism and geometry, as well as the dynamic process of hadron's electromagnetic decay, weak decay and strong decay. In nine months, they published 46 scientific papers and got a series of theoretical results, many of which were consistent with the experimental results. Some of them had no experimental data at that time and were later confirmed by experiments. There are still some theoretical results that are inconsistent with the experiment, which need to be solved through the new progress of later experiments and theoretical work. The "straton model" is an important development in the study of hadron structure and a directional systematic work before the theory of interstraton dynamics was put forward. The concept of overlapping integration of wave function and wave function in hadron internal structure put forward in this theory is still in use today. With the establishment of the dynamic theory of strong interaction between layers, they are determined more and more carefully. At 1966 Beijing Asia-Pacific Science Seminar, Pakistani Nobel Prize winner Salam spoke highly of this work. Unfortunately, Zhu Hongyuan and China's particle physicists made a good start in theory, which was interrupted by the great destruction in the following decade. Related viewpoints Nucleons (hadrons) are bound states of quarks and gluons, which are described by quantum chromodynamics QCD. Because of the basic characteristics of QCD (asymptotic freedom at high energy scale, color limitation at low energy scale and dynamic chiral symmetry breaking), the QCD image of nucleon (hadron) structure and properties is scale-related. At the high energy scale, the hadron is described by QCD parton model, which is related to the hard process of detecting hadron structure. The quark and gluon structure information of hadron is obtained by QCD partial summation rule. QCD perturbation theory is a suitable theory. At low energy level, QCD non-perturbation must be developed. Although the quark model achieved a lot of success at that time, it also encountered some troubles. For example, the quark structure theory of baryons holds that baryons like ω-and δ++can be composed of three identical quarks, all of which are in the ground state and have the same spin direction. This phenomenon that there are three identical particles at the same energy level violates the Pauli exclusion principle. Pauli exclusion principle says that two fermions cannot be in the same state. The spin of quarks is a semi-integer, which is a fermion. Of course, you can't violate the Pauli principle. But physicists have their own methods. Not to say that all three quarks are the same? Then I give them a number or a "color" (red, yellow and blue), and the three quarks will be different, so that they will no longer violate the Pauli principle. Indeed, in 1964, Greenberg introduced this degree of freedom of quarks-the concept of "color". Of course, the "color" here is not the color of visual perception, it is synonymous with a newly introduced degree of freedom, similar to the charge of electrons, quarks have color charges. In this way, each quark has three colors, and the variety of quarks has suddenly expanded from the original six to 18. Together with their antiparticles, there are 36 kinds of quarks in nature, which are associated with leptons (such as electrons, muons, τ ions and their corresponding neutrinos) and gauge particles (such as photons, three intermediate bosons and gauge particles that transmit weak interactions to control the decay of quarks and leptons). The theory that quarks have chromatic degrees of freedom has been supported by many experiments, and developed into an important strong interaction theory-quantum chromodynamics in 1970s. 1964, American physicists Murray gherman and G Zweig independently proposed that hadrons such as neutrons and protons are composed of quarks, a more basic unit. They have fractional charge, which is 2/3 times that of elementary charge or-1/3 times, and their spin is 1/2. The word quark is taken from James Joyce's novel A Night Sacrifice in finnigan, written by gherman. This is the "set mark of three quarks". Quarks have many meanings in this book, one of which is the sound of seabirds. He thinks this is suitable for his original strange idea that "elementary particles are not fundamental and elementary charge is not an integer", and he also points out that this is just a joke and a resistance to pretentious scientific language. In addition, it may be because of his love for birds.