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→Constructing a Feynman Diagram
: '''Feynman diagrams''' have [[time]] on the [[y-axis]] and space on the [[z-axis]].
: '''Feynman diagrams''' are used to simplify complex equations used to represent [[Subatomic Particle|subatomic particle]] [[Fundamental Interactions|interactions]].
: [[Subatomic Particle|Particles]] with a high [[velocity]] are seen as having shallow [[gradient]]s on a '''Feynman diagram''' since they travel a large distance in space over a short duration of [[time]].
===Constructing a Feynman Diagram===
: '''Feynman Diagrams''' can be constructed from the equations representing a [[Subatomic Particle|particle]] [[Fundamental Interactions|interaction]].
: The [[Subatomic Particle|particles]] at the start of the [[Nuclear Equation|equation]] are written at the bottom of the '''Feynman diagram''' while the [[product]]s are written at the top.
{| class="wikitable"
|+[[Electron Capture]]
| style="height:20px; width:200px; text-align:center;" |
<math>p + e^-</math>
| style="height:20px; width:200px; text-align:center;" |
<math>p + e^- \rightarrow n + \nu_e</math>
| style="height:20px; width:200px; text-align:center;" |
<math>p + e^- \xrightarrow{W^+} n + \nu_e</math>
|-
|[[File:FeynmanDiagramElectronCapturePt1.png|center|200px]]
|[[File:FeynmanDiagramElectronCapturePt2.png|center|200px]]
|[[File:FeynmanDiagramElectronCapture.png|center|200px]]
|-
| style="height:20px; width:200px; text-align:center;" |The [[Subatomic Particle|particles]] prior to the [[Fundamental Interactions|interaction]] are drawn first at the bottom of the '''Feynman diagram'''. Both the [[proton]] and [[electron]] in this '''diagram''' are drawn with a steep [[gradient]] to show their relatively small [[velocity]] compared to the [[Speed of Light|speed of light]].
| style="height:20px; width:200px; text-align:center;" |The [[Subatomic Particle|particles]] after the [[Fundamental Interactions|interaction]] are drawn at the top of the '''Feynman diagram'''. It should be recognised that [[Conservation of Baryon Number|baryon conservation]] means a [[baryon]] becomes another [[baryon]] and [[Conservation of Lepton Number|lepton conservation]] means that a [[lepton]] is transformed from one type of [[lepton]] into another. The [[Electron-neutrino|electron-neutrino]] in this [[diagram]] is drawn with a shallow [[gradient]] to show that it travels close to the [[Speed of Light|speed of light]].
| style="height:20px; width:200px; text-align:center;" |Finally the [[boson]] mediating the [[Fundamental Interactions|interaction]] is added as a [[wave]] between the two points of [[Fundamental Interactions|interaction]]. In this case a [[proton]] loses its [[Positive Charge|positive charge]] therefore it is carried away to the [[electron]] via the [[W-boson|W<sup>+</sup> boson]] transforming the [[electron]] into an [[Electron-neutrino|electron-neutrino]].
|}
{| class="wikitable"
|+Neutron Decay
| style="height:20px; width:200px; text-align:center;" |
<math>n \rightarrow</math>
| style="height:20px; width:200px; text-align:center;" |
<math>n \rightarrow p + \beta^- + \bar\nu_e</math>
| style="height:20px; width:200px; text-align:center;" |
<math>n \xrightarrow{W^-} p + \beta^- + \bar\nu_e</math>
|-
|[[File:FeynmanDiagramNeutronDecayPt1.png|center|200px]]
|[[File:FeynmanDiagramNeutronDecayPt2.png|center|200px]]
|[[File:FeynmanDiagramNeutronDecay.png|center|200px]]
|-
| style="height:20px; width:200px; text-align:center;" |The [[Subatomic Particle|particles]] prior to the [[Fundamental Interactions|interaction]] are drawn first at the bottom of the '''Feynman diagram'''. The [[neutron]] in this '''diagram''' is drawn with a steep [[gradient]] to show it has a relatively small [[velocity]] compared to the [[Speed of Light|speed of light]].
| style="height:20px; width:200px; text-align:center;" |The [[Subatomic Particle|particles]] after the [[Fundamental Interactions|interaction]] are drawn at the top of the '''Feynman diagram'''. It should be recognised that [[Conservation of Baryon Number|baryon conservation]] means a [[baryon]] becomes another [[baryon]] and [[Conservation of Lepton Number|lepton conservation]] means that if a [[lepton]] comes into existence there must also be an [[antilepton]]. The [[antielectron-neutrino|antielectron-neutrino]] in this [[diagram]] is drawn with a shallow [[gradient]] to show that it travels close to the [[Speed of Light|speed of light]].
| style="height:20px; width:200px; text-align:center;" |Finally the [[boson]] mediating the [[Fundamental Interactions|interaction]] is added as a [[wave]] between the two points of [[Fundamental Interactions|interaction]]. In this case a [[neutron]] loses a [[Negative Charge|negative charge]] therefore it is carried away to produce the [[electron]] via the [[W-boson|W<sup>-</sup> boson]] also producing an [[antielectron-neutrino]].
|}
===Examples===
|-
| style="height:20px; width:300px; text-align:center;" |This '''Feynman diagram''' shows the [[Electromagnetic Interaction|electromagnetic interaction]] between two [[proton]]s via the virtual [[photon]].
| style="height:20px; width:300px; text-align:center;" |This '''Feynman diagram''' shows the [[Weak Nuclear Interaction|weak interaction]] in which a [[neutron]] [[Radioactive Decay|decays]] into a [[proton]].
<math>n \xrightarrow{W^-} rightarrow p + \beta^- + \bar\nunu_e</math>
|-
|[[File:FeynmanDiagramElectronCapture.png|center|300px]]
|[[File:FeymanDiagramUpDecayFeynmanDiagramUpDecay.png|center|300px]]
|-
| style="height:20px; width:300px; text-align:center;" |TextThis '''Feynman diagram''' shows the [[Weak Nuclear Interaction|weak interaction]] in which a [[proton]] [[Electron Capture|captures]] an [[electron]] to become a [[neutron]]. <math>p + e^- \rightarrow n + \nu_e</math> | style="height:20px; width:300px; text-align:center;" |TextThis '''Feynman diagram''' shows the [[Weak Nuclear Interaction|weak interaction]] in which an [[up-quark]] [[Radioactive Decay|decays]] into a [[down-quark]], which is observed as a [[proton]] [[Radioactive Decay|decaying]] into a [[neutron]] via [[Beta Particle|beta]] emission. <math>u \rightarrow d + \beta^+ + \nu_e</math>
|}