User:John R. Brews/Sample2: Difference between revisions
imported>John R. Brews |
imported>John R. Brews |
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===Leptons=== | ===Leptons=== | ||
[[Lepton]]s are spin 1/2 | [[Lepton]]s are a ''type'' of particle with spin 1/2 that are not subject to the strong force. The known leptons are listed in the table below. Their antiparticles also are leptons with opposite [[electric charge]] ''Q'' and opposite Lepton number ''L<sub>e,μ,τ</sub>''. | ||
{| class="wikitable" style="text-align:center" | {| class="wikitable" style="text-align:center" | ||
|+Properties of leptons | |+Properties of leptons | ||
|- | |- | ||
! Particle | ! Particle name | ||
! Symbol | ! Symbol | ||
! Family/Generation | |||
! [[Electric charge|Q]] ([[elementary charge|e]]) | ! [[Electric charge|Q]] ([[elementary charge|e]]) | ||
! L<sub>e</sub> | ! L<sub>e</sub> | ||
! L<sub>μ</sub> | ! L<sub>μ</sub> | ||
| Line 21: | Line 21: | ||
! Mass (MeV/c<sup>2</sup>) | ! Mass (MeV/c<sup>2</sup>) | ||
! Lifetime ([[second|s]]) | ! Lifetime ([[second|s]]) | ||
|- | |- | ||
|style="text-align:left"| [[Electron]] | |style="text-align:left"| [[Electron]] | ||
| ''e<sup>−</sup>'' | | ''e<sup>−</sup>'' | ||
| 1 | |||
| −1 | | −1 | ||
| +1 | | +1 | ||
| 0 | | 0 | ||
| Line 32: | Line 32: | ||
| 0.510998910(13) | | 0.510998910(13) | ||
| Stable | | Stable | ||
|- | |- | ||
|style="text-align:left"| [[Muon]] | |style="text-align:left"| [[Muon]] | ||
| ''μ<sup>−</sup>'' | | ''μ<sup>−</sup>'' | ||
| 2 | |||
|−1 | |−1 | ||
| 0 | | 0 | ||
| +1 | | +1 | ||
| Line 43: | Line 43: | ||
| 105.6583668(38) | | 105.6583668(38) | ||
| 2.197019(21) × 10<sup>−6</sup> | | 2.197019(21) × 10<sup>−6</sup> | ||
|- | |- | ||
|style="text-align:left"| [[Tau]] | |style="text-align:left"| [[Tau]] | ||
| ''τ<sup>−</sup> | | ''τ<sup>−</sup> | ||
| 3 | |||
| −1 | | −1 | ||
| 0 | | 0 | ||
| 0 | | 0 | ||
| Line 54: | Line 54: | ||
| 1776.84(17) | | 1776.84(17) | ||
| 2.906(10) × 10<sup>-13</sup> | | 2.906(10) × 10<sup>-13</sup> | ||
|- | |- | ||
|style="text-align:left"| [[Electron neutrino]] | |style="text-align:left"| [[Electron neutrino]] | ||
| ''ν<sub>e</sub>'' | | ''ν<sub>e</sub>'' | ||
| 1 | |||
| 0 | | 0 | ||
| +1 | | +1 | ||
| 0 | | 0 | ||
| Line 65: | Line 65: | ||
| < 0.0000022 | | < 0.0000022 | ||
| Unknown | | Unknown | ||
|- | |- | ||
|style="text-align:left"| [[Muon neutrino]] | |style="text-align:left"| [[Muon neutrino]] | ||
| ''ν<sub>μ</sub>'' | | ''ν<sub>μ</sub>'' | ||
| 2 | |||
| 0 | | 0 | ||
| 0 | | 0 | ||
| +1 | | +1 | ||
| Line 76: | Line 76: | ||
| < 0.17 | | < 0.17 | ||
| Unknown | | Unknown | ||
|- | |- | ||
|style="text-align:left"| [[Tau neutrino]] | |style="text-align:left"| [[Tau neutrino]] | ||
| ''ν<sub>τ</sub>'' | | ''ν<sub>τ</sub>'' | ||
| 3 | |||
| 0 | | 0 | ||
| 0 | | 0 | ||
| 0 | | 0 | ||
| Line 87: | Line 87: | ||
| < 15.5 | | < 15.5 | ||
| Unknown | | Unknown | ||
|} | |} | ||
Revision as of 15:15, 28 August 2011
The Standard Model of particle physics is the mathematical theory that describes the weak, electromagnetic and strong interactions between leptons and quarks, the basic particles of particle physics. This model is very strongly supported by experimental observations, and is considered to be a major achievement (perhaps the most outstanding achievement) of theoretical physics. It does not, however, treat the gravitational force, inclusion of which remains an elusive goal of the ultimate "theory of everything". The Standard Model is accordingly not consistent with general relativity. The theory is consistent with special relativity.
The model is only qualitatively described in this article, and mathematical details are not provided. To begin, the basic particles in the Standard Model and their interactions are introduced.
Particles and interactions
The interactions between the particles of the Standard Model are well known experimentally, and transcend the Standard Model. However, the particles of the Standard Model are introduced with the ways that they use these interactions to assemble a complete theory of the interactions between various manifestations of matter. The fundamental particles are spin 1/2 fermions, and their interactions are viewed as exchange forces, which is to say the forces are introduced by the trading back and forth of force carriers, different kinds of particle that represent quanta of the underlying force fields. So, for example, the quanta of the electromagnetic field are photons. The strength of an electromagnetic field is dictated by the number of photons that make it up, and the exchange of photons between particles with electric charge is the mechanism underlying the field's ability to exert an electromagnetic force upon these bodies.
Leptons
Leptons are a type of particle with spin 1/2 that are not subject to the strong force. The known leptons are listed in the table below. Their antiparticles also are leptons with opposite electric charge Q and opposite Lepton number Le,μ,τ.
| Particle name | Symbol | Family/Generation | Q (e) | Le | Lμ | Lτ | Mass (MeV/c2) | Lifetime (s) |
|---|---|---|---|---|---|---|---|---|
| Electron | e− | 1 | −1 | +1 | 0 | 0 | 0.510998910(13) | Stable |
| Muon | μ− | 2 | −1 | 0 | +1 | 0 | 105.6583668(38) | 2.197019(21) × 10−6 |
| Tau | τ− | 3 | −1 | 0 | 0 | +1 | 1776.84(17) | 2.906(10) × 10-13 |
| Electron neutrino | νe | 1 | 0 | +1 | 0 | 0 | < 0.0000022 | Unknown |
| Muon neutrino | νμ | 2 | 0 | 0 | +1 | 0 | < 0.17 | Unknown |
| Tau neutrino | ντ | 3 | 0 | 0 | 0 | +1 | < 15.5 | Unknown |