Balanced prime: Difference between revisions
en>Markhurd Mention balanced primes of order n |
Link redirect delete |
||
| Line 1: | Line 1: | ||
Weak '''neutral current''' interactions are one of the ways in which [[subatomic particle]]s can interact by means of the [[weak force]]. These interactions are mediated by the {{SubatomicParticle|link=yes|Z boson}} [[boson]]. The discovery of weak neutral currents was a significant step toward the unification of [[electromagnetism]] and the weak force into the [[electroweak force]], and led to the discovery of the [[W and Z bosons]]. | |||
== Definition == | |||
The neutral current that gives the interaction its name is that of the interacting particles. For example, the neutral-current contribution to the {{SubatomicParticle|Electron neutrino}}{{SubatomicParticle|Electron}} → {{SubatomicParticle|Electron neutrino}}{{SubatomicParticle|Electron}} elastic scattering amplitude | |||
:<math>\mathfrak{M}^{\mathrm{NC}} \propto J_{\mu}^{\mathrm{(NC)}}(\nu_{\mathrm{e}}) \; J^{\mathrm{(NC)}\mu}(\mathrm{e^{-}})</math> | |||
where the neutral currents describing the flow of the neutrino and of the electron are given by | |||
:<math>J^{\mathrm{(NC)}\mu}(f) = \bar{u}_{f}\gamma^{\mu}\frac{1}{2}\left(g^{f}_{V}-g^{f}_{A}\gamma^{5}\right)u_{f},</math> | |||
and <math>g^{f}_{V}</math> and <math>g^{f}_{A}</math> are the [[Coordinate vector|vector]] and [[axial vector]] couplings for [[fermion]] <math>f</math>. | |||
The {{SubatomicParticle|Z boson}} boson can couple to any Standard Model particle, except [[gluon]]s and [[photon]]s. However, any interaction between two charged particles that can occur via the exchange of a virtual {{SubatomicParticle|Z boson}} boson can also occur via the exchange of a virtual [[photon]]. Unless the interacting particles have energies on the order of the {{SubatomicParticle|Z boson}} boson mass (91 GeV) or higher, the virtual {{SubatomicParticle|Z boson}} boson exchange has an effect of a tiny correction ( <math>~(E/M_Z)^2</math> ) to the amplitude of the electromagnetic process. Particle accelerators with energies necessary to observe neutral current interactions and to measure the mass of {{SubatomicParticle|Z boson}} boson weren't available until 1983. | |||
On the other hand, {{SubatomicParticle|Z boson}} boson interactions involving [[neutrino]]s have distinctive signatures: They provide the only known mechanism for [[elastic scattering]] of neutrinos in matter; neutrinos are almost as likely to scatter elastically (via {{SubatomicParticle|Z boson}} boson exchange) as inelastically (via {{SubatomicParticle|link=yes|W boson}} boson exchange). Weak neutral currents were predicted in 1973 by [[Abdus Salam]], [[Sheldon Glashow]] and [[Steven Weinberg]],<ref>{{cite web|title=The Nobel Prize in Physics 1979|url=http://www.nobel.se/physics/laureates/1979|publisher=[[Nobel Foundation]]|accessdate=2008-09-10}}</ref> and confirmed shortly thereafter in 1974, in a neutrino experiment in the [[Gargamelle]] [[bubble chamber]] at [[CERN]]. | |||
== See also == | |||
* [[Charged current]] | |||
* [[Flavor changing neutral current]] | |||
* [[Quantum chromodynamics]] | |||
== References == | |||
{{Reflist}} | |||
== External links == | |||
* [http://cerncourier.com/cws/article/cern/29168 ''THE DISCOVERY OF WEAK NEUTRAL CURRENTS'', CERN Courier] | |||
* [http://public.web.cern.ch/public/en/Research/Gargamelle-en.html public web CERN] | |||
* [http://www.britannica.com/EBchecked/topic/410842/neutral-current-interaction britannica] | |||
* [http://hyperphysics.phy-astr.gsu.edu/hbase/particles/neucur.html R Nave] | |||
* http://www.actaphys.uj.edu.pl/vol37/pdf/v37p2295.pdf | |||
* http://www.symmetrymagazine.org/breaking/2009/07/07/gargamelle/ | |||
* [http://cerncourier.com/cws/article/cern/27904 cerncourier] | |||
* {{cite web|last=Padilla|first=Antonio (Tony)|title=Gargamelle and Neutral Currents|url=http://www.sixtysymbols.com/videos/neutral_currents.htm|work=Sixty Symbols|publisher=[[Brady Haran]] for the [[University of Nottingham]]}} | |||
{{particle-stub}} | |||
[[Category:Particle physics]] | |||
Revision as of 17:52, 7 January 2014
Weak neutral current interactions are one of the ways in which subatomic particles can interact by means of the weak force. These interactions are mediated by the Template:SubatomicParticle boson. The discovery of weak neutral currents was a significant step toward the unification of electromagnetism and the weak force into the electroweak force, and led to the discovery of the W and Z bosons.
Definition
The neutral current that gives the interaction its name is that of the interacting particles. For example, the neutral-current contribution to the Template:SubatomicParticleTemplate:SubatomicParticle → Template:SubatomicParticleTemplate:SubatomicParticle elastic scattering amplitude
where the neutral currents describing the flow of the neutrino and of the electron are given by
and and are the vector and axial vector couplings for fermion .
The Template:SubatomicParticle boson can couple to any Standard Model particle, except gluons and photons. However, any interaction between two charged particles that can occur via the exchange of a virtual Template:SubatomicParticle boson can also occur via the exchange of a virtual photon. Unless the interacting particles have energies on the order of the Template:SubatomicParticle boson mass (91 GeV) or higher, the virtual Template:SubatomicParticle boson exchange has an effect of a tiny correction ( ) to the amplitude of the electromagnetic process. Particle accelerators with energies necessary to observe neutral current interactions and to measure the mass of Template:SubatomicParticle boson weren't available until 1983.
On the other hand, Template:SubatomicParticle boson interactions involving neutrinos have distinctive signatures: They provide the only known mechanism for elastic scattering of neutrinos in matter; neutrinos are almost as likely to scatter elastically (via Template:SubatomicParticle boson exchange) as inelastically (via Template:SubatomicParticle boson exchange). Weak neutral currents were predicted in 1973 by Abdus Salam, Sheldon Glashow and Steven Weinberg,[1] and confirmed shortly thereafter in 1974, in a neutrino experiment in the Gargamelle bubble chamber at CERN.
See also
References
43 year old Petroleum Engineer Harry from Deep River, usually spends time with hobbies and interests like renting movies, property developers in singapore new condominium and vehicle racing. Constantly enjoys going to destinations like Camino Real de Tierra Adentro.