Particle physics, is a research componentmaterialandradialOfElementary particleAnd the interaction between themphysicsBranch.Because many elementary particlesnatureDoes not exist or appears separately under the general conditions ofParticle acceleratorThey can only be produced and studied under the condition of high-energy collisions, so particle physics is also calledhigh-energy physics。
Chinese name
Particle physics
Foreign name
particle physics
Alias
High-energy physics
Status
The Grand Unity of Particle Physics of Particle Quantization
Particle physicsIs a research componentmaterialandradialOfElementary particleAnd the interaction between themphysicsBranch.Because many elementary particlesnatureDoes not exist or appears separately under the general conditions ofParticle acceleratorThey can only be produced and studied under the condition of high-energy collisions, so particle physics is also calledhigh-energy physics。[1]
Subatomic particle
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Diagram of atomic particle electron, proton and neutron internal structure model
The research of modern particle physics focuses onSubatomic particleOn.The structural ratio of these particlesatomSmall, including atomic components such asElectronics、protonandneutron(Protons and neutrons themselves arequarkAnd particles caused by radiation and scattering, such asphoton、neutrinoandMuon, and many other exotic particles.
Strictly speaking“particle”This name is imprecise. All objects studied in particle physics comply withquantum mechanicsRules, they all displayWave particle dualityAccording to different experimental conditions, they show the characteristics of particles orwaveProperties of.In physical theory, they are neither particles nor waves, and theorists useHilbert spaceThe detailed theoretical basis isQuantum field theory。But according toParticle physicsIn this article, these objects are still called "particles", although these particles also have wave characteristics.
All the basic particles known today can be used in a method called particle physicsStandard modelQuantum field theory.Standard modelIt is the best theory in particle physics at present, including 37 kindsElementary particleThese basic particles can combine with each other to form more complex particles.Since the 1960s, experimental physicists have discovered and observed hundreds ofComposite particleHas.The standard model theory is almost consistent with all the experimental data observed so far.However, most particle physicists believe that it is still an imperfect theory, and a more basic theory has yet to be discovered.Recently discoveredneutrinoNon zero static mass is the first andStandard modelExperimental observation with deviation.[1]
history
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The first six centuriesancient GreekThe philosopher ofmaterialIt is a guess made up of elementary particles.Liusipus、DemocritusandEpicurusHe is the representative of "atomism".In the 17th centuryIsaac NewtonThere was also the idea that matter was composed of particles.1802John DaltonFormally put forward the theory that all substances are composed of atoms.
Twentieth CenturyAtomic physicsandQuantum physics's research led tofissionandfusionThe discovery and experiment were successful.Humans can convert atoms of one element into atoms of another.
In the 1950s and 1960s, many new particles were discovered, which were collectively called "particle zoos".Until the 1970s, particle physicsStandard modelEstablish, regard most of these particles as a fewElementary particleOfComposite particleOnly then did the confusion abate.[1]
German electron accelerator: atGermanyhamburgerIts main equipment isHadron electron ring equipment(HERA), available electronically andpositronCollide with a proton.
Theoretical particle physics attempts to describe all interactions in nature and to study models, theoretical frameworks and mathematical tools that can explain today's experimental results and predict future experimental results.There are many different efforts in this regard today.
An important work point is to better understand the standard model theory and its experimental results, and obtain more accurate parameters from experiments. This work point tests the limits of the standard model theory to expand our understanding of nature.The biggest difficulty of this job isQuantum chromodynamicsDifficulties in computing multiple objects.Some theorists focus their energies onEffective field theory。
Another important work point is to establish models beyond the standard model theory.Because today's experimental data is not enough, this work is very difficult.The new theoretical structure includesSupersymmetry、Ruan Sang model、PrononTheory and so on.
The third important point isString theoryIts purpose is to establish a theory based on tiny strings and membranes rather than particles to uniformly describe quantum mechanics andGeneral relativity。If this theory succeeds, it can be regarded as a“Theory of everything”。
Reductionism is a philosophical viewpoint that simplifies the explanation of things in the world to some basic theories.In particle physics, it is the most basic physical theory that can explain everything in the world, or in a popular language, to find a formula that summarizes everything in the universe.
But in the development of particle physics, some people have criticized this extreme reductionism.Among these critics are particle physicistsChemistryHomebiologyHomeSolid State PhysicsHome andHolismThe.They do not challenge the standard model theory itself, but they believe that the characteristics of elementary particles are not necessarily the characteristics of the atoms, molecules or larger structures they form, especially they cannot express the characteristics of systems composed of many particles.be based onchaos theory Some critics believe that even if physicists fully understand all the characteristics of elementary particles, people cannot fully understand all the natural processes;Other critics doubt that people can fully understand the characteristics of elementary particles.[1]
public policy
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The experimental results of particle physics need to use hugeParticle acceleratorCan be obtained.These accelerators are very expensive (often requiring billions of dollars) and therefore require substantial government funding.Therefore, the research of particle physics is also related to the decision of public policy.
Many people think it is not worth spending so much money, and particle physics consumes a lot of money that can be used for more important research and education.In the 1980s, the construction of a super superconducting collider began in Texas, the United States. This was a grand plan, costing as much as 8 billion dollars. The United States Congress spent 2 billion dollars on this, and cancelled the project after the construction of a 22 km tunnel.Many scientists (includingSuperconducting super large acceleratorOne of the reasons for believing this decision is becauseCold WarIt is unnecessary for the United States to spend so much money on this aspectSoviet UnionCompetition.
In addition, many opponents doubt whether a single country can still run such an expensive collider.
Some people in the scientific community believe thatAging of the populationIt is bad for particle physics, because they think that older people are more concerned about immediate things, such as their health and their parents' health, so the funding for science has gradually shifted from physics to biology and health science.
Supporters of particle physics believe that it is worthwhile to spend so much money for the most basic theory, which is also good for other aspects of science.For example, accelerators and their by-productssynchrotron radiationIts application in biology and medicine, and its earliestCERNCreated by researchersweb。They pointed out that all accelerators today are established and operated through international cooperation, and they doubted that the budget saved by canceling the manufacturing of accelerators would still be used in other aspects of science and education.[1]
expectation
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Particle physicists around the world agree on the most important goals of particle physics in the near and medium term.The near-term goal is to complete in 2007Large Hadron ColliderAnd use it to findHiggs bosonandSupersymmetric particle。The medium-term goal is to buildInternational Linear Collider(International_Linear_Collider, ILC). The technical implementation method of this collider has been decided in August 2004, but the specific address has not yet been decided.The International Linear Collider and the Large Hadron Collider are complementary experimental equipment. The Large Hadron Collider is more suitable for finding new particles, while the International Linear Collider is more suitable for accurately measuring the characteristics of these particles.
Other important objectives of particle physics include measurementneutrinoStatic mass and clarification ofprotonThe double ofBeta decayExists.These experiments do not necessarily require the use of colliders.[1]
