Standard Model (Wikipedia)

At present, matter and energy are best understood in terms of the kinematics and interactions of elementary particles. To date, physics has reduced the laws governing the behavior and interaction of all known forms of matter and energy to a small set of fundamental laws and theories. A major goal of physics is to find the “common ground” that would unite all of these theories into one integrated theory of everything, of which all the other known laws would be special cases, and from which the behavior of all matter and energy could be derived (at least in principle)
Particle content
The Standard Model includes members of several classes of elementary particles (fermions, gauge bosons, and the Higgs boson), which in turn can be distinguished by other characteristics, such as color charge.
All particles can be summarized as follows:
Elementary particles
Generations: quarks
Up-type               Down-type
1. Up (u),            Down (d)
2. Charm (c),    Strange (s)
3. Top (t),           Bottom (b)
Generation: leptons
Charged                     Neutral
1. Electron (e−),    Electron neutrino (νe)
2. Muon (μ−),           Muon neutrino (νμ)
3. Tau (τ−),                Tau neutrino (ντ)
Four kinds (four fundamental interactions)
1. Photon (γ, Electromagnetic interaction)
2. W and Z bosons (W+, W−, Z, weak interaction)
3. Eight types of gluons (g, Strong interaction)
4. Graviton (G, Gravity, hypothetical)
Higgs boson
1. The antielectron (e+) is traditionally called positron
2. The known force carrier bosons all have spin = 1 and are therefore vector bosons. The hypothetical graviton has spin = 2 and is a tensor boson; if it is a gauge boson as well is unknown.
Summary of interactions between particles described by the Standard Model.
The Standard Model includes 12 elementary particles of spin  1⁄2 known as fermions. According to the spin-statistics theorem, fermions respect the Pauli exclusion principle. Each fermion has a corresponding antiparticle.
The fermions of the Standard Model are classified according to how they interact (or equivalently, by what charges they carry). There are six quarks (up, down, charm, strange, top, bottom), and six leptons (electron, electron neutrino, muon, muon neutrino, tau, tau neutrino). Pairs from each classification are grouped together to form a generation, with corresponding particles exhibiting similar physical behavior (see table).
The defining property of the quarks is that they carry color charge, and hence, interact via the strong interaction. A phenomenon called color confinement results in quarks being very strongly bound to one another, forming color-neutral composite particles (hadrons) containing either a quark and an antiquark (mesons) or three quarks (baryons). The familiar proton and neutron are the two baryons having the smallest mass. Quarks also carry electric charge and weak isospin. Hence, they interact with other fermions both electromagnetically and via the weak interaction.
The remaining six fermions do not carry colour charge and are called leptons. The three neutrinos do not carry electric charge either, so their motion is directly influenced only by the weak nuclear force, which makes them notoriously difficult to detect.
However, by virtue of carrying an electric charge, the electron, muon, and tau all interact electromagnetically.
Each member of a generation has greater mass than the corresponding particles of lower generations. The first generation charged particles do not decay; hence all ordinary (baryonic) matter is made of such particles. Specifically, all atoms consist of electrons orbiting around atomic nuclei, ultimately constituted of up and down quarks. Second and third generation charged particles, on the other hand, decay with very short half lives, and are observed only in very high-energy environments. Neutrinos of all generations also do not decay, and pervade the universe, but rarely interact with baryonic matter.

Generations of matter

Type First Second Third
up-type up charm top
down-type down strange bottom
charged electron muon tau
neutral electron neutrino muon neutrino tau neutrino

Fermions and bosons

Those particles with half-integer spins, such as 1/2, 3/2, 5/2, are known as fermions, while those particles with integer spins, such as 0, 1, 2, are known as bosons. The two families of particles obey different rules and broadly have different roles in the world around us. A key distinction between the two families is that fermions obey the Pauli exclusion principle; that is, there cannot be two identical fermions simultaneously having the same quantum numbers (meaning, roughly, having the same position, velocity and spin direction). In contrast, bosons obey the rules of Bose–Einstein statistics and have no such restriction, so they may “bunch together” even if in identical states. Also, composite particles can have spins different from their component particles. For example, a helium atom in the ground state has spin 0 and behaves like a boson, even though the quarks and electrons which make it up are all fermions.

This has profound consequences:

  • Quarks and leptons (including electrons and neutrinos), which make up what is classically known as matter, are all fermions with spin 1/2. The common idea that “matter takes up space” actually comes from the Pauli exclusion principle acting on these particles to prevent the fermions that make up matter from being in the same quantum state. Further compaction would require electrons to occupy the same energy states, and therefore a kind of pressure (sometimes known as degeneracy pressure of electrons) acts to resist the fermions being overly close.
Elementary fermions with other spins (3/2, 5/2, etc.) are not known to exist.
Elementary bosons with other spins (0, 2, 3 etc.) were not historically known to exist, although they have received considerable theoretical treatment and are well established within their respective mainstream theories. In particular, theoreticians have proposed the graviton (predicted to exist by some quantum gravity theories) with spin 2, and the Higgs boson (explaining electroweak symmetry breaking) with spin 0. Since 2013, the Higgs boson with spin 0 has been considered proven to exist. It is the first scalar elementary particle (spin 0) known to exist in nature.


A Wikipédiából, a szabad enciklopédiából
Szokásos és egzotikus hadronok

A részecskefizikában hadronnak nevezzük az olyan összetett szubatomi részecskéket, amelyeknek összetevői kvarkok és gluonok

A „hagyományos” hadronok a Gell-Mann kvarkmodelljének megfelelő, azaz 3 kvarkból vagy kvark-antikvark párból álló hadronok.
Ezek között:

1/ A barionok három kvarkból (az antibarionok pedig három antikvarkból) álló feles spinű részecskék, azaz fermionok.
Fő példái a nukleonok: a proton és a neutron

2/A mezonok egy kvarkból és egy antikvarkból állnak, mint a pionok, kaonok és egy csomó más részecske. Egyes spinű részecskék, azaz bozonok.

Egyfajta sematikus ábrázolásuk is elérhető volt. L. alább:




3 thoughts on “Standard Model (Wikipedia)

  1. Ezt olvastam hozzá(d) a Wikiben: A szokásos barionok három kvarkból álló részecskék. Közéjük tartoznak a proton és a neutron – együttes nevükön nukleonok –, valamint az összes többi nehezebb barion – a hiperonok. A “barion” kifejezés a görög “barüsz” (“nehéz”) szóból származik, mivel nehezebbek, mint a részecskék többi fő csoportja.A barionok a mezonokkal együtt a hadronok közé tartoznak, azaz kvarkokból épülnek fel. A barionok három kvarkból, a mezonok egy kvarkból és egy antikvarkból állnak.


  2. A Standard Modellből annyit mindenesetre értek, hogy az anyagból az első generáció (up, down kvarkok, lepton) tartós létét tapasztaljuk és tartalmazzuk barion (trikvark) formában. A második, harmadik generáció hamar elbomlik, szemben az élő világgal, melyben a további generációk nem kevésbé maradandók.


  3. The Atlantic egyik multkori száma írt a lepton tábládban szereplő műonokról és gyakorlati alkalmazásukról. (They discovered a) “previously unknown “void” in the Great Pyramid.
    This discovery comes by way of cosmic rays. When these high-energy rays hit atoms in the Earth’s atmosphere, they send subatomic particles called muons shooting toward the ground. The muons can be slowed down by large masses—like the rocks that make up the Great Pyramid. And if muons pass through a cavity inside a large mass, that cavity will show up on muon detectors, too.”


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