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# Baždarni bozoni — разлика између измена

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Baždarni bozoni su bozoni koji deluju kao prenosnici fundamentalnih interakcija, što se detaljnije može opisati tako da elementarne čestice čija međudelovanja opisuje baždarna teorija jedne na drugu deluju silom tako da između sebe razmenjuju baždarne bozone, obično u obliku virtualnih čestica.[1][2][3]

U Standardnom modelu poznate su tri vrste baždarnih bozona: fotoni, W i Z bozoni, te gluoni. Svaki su od njih odgovorni za jedno međudelovanje: fotoni su baždarni bozoni elektromagnetske sile, W i Z bozoni prenose slabu nuklearnu silu, a gluoni jaku nuklearnu silu. Za gravitaciju se takođe pretpostavlja da bi se mogla prenositi hipotetskim baždarnim bozonom koji je nazvan graviton.

All known gauge bosons have a spin of 1; for comparison, the Higgs boson has spin zero. Therefore, all known gauge bosons are vector bosons. Gauge bosons are different from the other kinds of bosons: first, fundamental scalar bosons (the Higgs boson); second, mesons, which are composite bosons, made of quarks; third, larger composite, non-force-carrying bosons, such as certain atoms.

## Baždarni bozoni u Standardnom modelu

Standardni model of particle physics recognizes four kinds of gauge bosons:[4][5] photons, which carry the electromagnetic interaction; W and Z bosons, which carry the weak interaction; and gluons, which carry the strong interaction.[6]

Isolated gluons do not occur because they are colour-charged[7] and subject to colour confinement.[8][9]

### Multiplicity of gauge bosons

In a quantized gauge theory, gauge bosons are quanta of the gauge fields.[10][11] Consequently, there are as many gauge bosons as there are generators of the gauge field. In quantum electrodynamics, the gauge group is U(1); in this simple case, there is only one gauge boson, the photon. In quantum chromodynamics, the more complicated group SU(3) has eight generators, corresponding to the eight gluons. The three W and Z bosons correspond (roughly) to the three generators of SU(2) in GWS theory.

### Massive gauge bosons

For technical reasons involving gauge invariance, gauge bosons are described mathematically by field equations for massless particles. Therefore, at a naïve theoretical level, all gauge bosons are required to be massless, and the forces that they describe are required to be long-ranged. The conflict between this idea and experimental evidence that the weak and strong interactions have a very short range requires further theoretical insight.

According to the Standard Model, the W and Z bosons gain mass via the Higgs mechanism. In the Higgs mechanism, the four gauge bosons (of SU(2)×U(1) symmetry) of the unified electroweak interaction couple to a Higgs field. This field undergoes spontaneous symmetry breaking due to the shape of its interaction potential. As a result, the universe is permeated by a nonzero Higgs vacuum expectation value (VEV). This VEV couples to three of the electroweak gauge bosons (the Ws and Z), giving them mass; the remaining gauge boson remains massless (the photon). This theory also predicts the existence of a scalar Higgs boson, which has been observed in experiments at the LHC.[12]

## Izvan standardnog modela

### Velike ujedinjavajuće teorije

The Georgi–Glashow model predicts additional gauge bosons named X and Y bosons. The hypothetical X and Y bosons mediate interactions between quarks and leptons, hence violating conservation of baryon number and causing proton decay. Such bosons would be even more massive than W and Z bosons due to symmetry breaking. Analysis of data collected from such sources as the Super-Kamiokande neutrino detector has yielded no evidence of X and Y bosons.

### Gravitoni

The fourth fundamental interaction, gravity, may also be carried by a boson, called the graviton. In the absence of experimental evidence and a mathematically coherent theory of quantum gravity, it is unknown whether this would be a gauge boson or not. The role of gauge invariance in general relativity is played by a similar symmetry: diffeomorphism invariance.

### W' i Z' bozoni

W' and Z' bosons refer to hypothetical new gauge bosons (named in analogy with the Standard Model W and Z bosons).

## Reference

1. ^ Gribbin, John (2000). Q is for Quantum – An Encyclopedia of Particle Physics. Simon & Schuster. ISBN 978-0-684-85578-3.
2. ^ Clark, John E.O. (2004). The Essential Dictionary of Science. Barnes & Noble. ISBN 978-0-7607-4616-5.
3. ^ Clark, John, E.O. (2004). The Essential Dictionary of Science. Barnes & Noble. ISBN 0-7607-4616-8.
4. ^ R. Oerter (2006). The Theory of Almost Everything: The Standard Model, the Unsung Triumph of Modern Physics (Kindle изд.). Penguin Group. стр. 2. ISBN 978-0-13-236678-6.
5. ^ R. Mann (2010). An Introduction to Particle Physics and the Standard Model. CRC Press. ISBN 978-1-4200-8298-2.
6. ^ Veltman, Martinus (2003). Facts and Mysteries in Elementary Particle Physics. World Scientific. ISBN 981-238-149-X.
7. ^ Feynman, Richard (1985), QED: The Strange Theory of Light and Matter, Princeton University Press, ISBN 978-0-691-08388-9
8. ^ Barger, V.; Phillips, R. (1997). Collider Physics. Addison–Wesley. ISBN 978-0-201-14945-6.
9. ^ Greensite, J. (2011). An introduction to the confinement problem. Lecture Notes in Physics. 821. Springer. Bibcode:2011LNP...821.....G. ISBN 978-3-642-14381-6. doi:10.1007/978-3-642-14382-3.
10. ^ Seiberg, N.; Witten, E. (1994a), „Electric-magnetic duality, monopole condensation, and confinement in N=2 supersymmetric Yang-Mills theory”, Nuclear Physics B, 426 (1): 19—52, Bibcode:1994NuPhB.426...19S, MR 1293681, arXiv:, doi:10.1016/0550-3213(94)90124-4; „Erratum”, Nuclear Physics B, 430 (2): 485—486, 1994, Bibcode:1994NuPhB.430..485., MR 1303306, doi:10.1016/0550-3213(94)00449-8
11. ^ Seiberg, N.; Witten, E. (1994b), „Monopoles, duality and chiral symmetry breaking in N=2 supersymmetric QCD”, Nuclear Physics B, 431 (3): 484—550, Bibcode:1994NuPhB.431..484S, MR 1306869, arXiv:, doi:10.1016/0550-3213(94)90214-3
12. ^ „CERN and the Higgs boson”. CERN. Архивирано из оригинала 23. 11. 2016. г. Приступљено 23. 11. 2016.