Question about Feynman diagram showing annihilation

In summary, the discussion revolves around a Feynman diagram depicting the annihilation process, typically involving a particle and its antiparticle colliding to produce other particles. The diagram illustrates the interaction vertices, particle lines, and the conservation of quantum numbers, such as energy, momentum, and charge. Questions may arise regarding the interpretation of specific elements within the diagram, the nature of the resulting particles, or the implications for particle physics theories.
  • #1
songoku
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Homework Statement
Please see below
Relevant Equations
Feynman Diagram
1713001049977.png


This is Feynman diagram of annihilation I get from wikipedia
https://en.wikipedia.org/wiki/Annihilation

I don't understand what the middle line with arrow to the right is. If I consider the left vertex and conservation of charge, it means the horizontal line with arrow to the right should carry negative charge. So it is W-?

Thanks
 
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  • #2
It is an electron line.

A W-line would violate both Lorentz symmetry and electroweak gauge symmetry.
 
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  • #3
Orodruin said:
It is an electron line.

A W-line would violate both Lorentz symmetry and electroweak gauge symmetry.
Can the horizontal line be removed so the diagram only shows two lines (one for electron and one for positron) and two photons?

Thanks
 
  • #4
songoku said:
Can the horizontal line be removed so the diagram only shows two lines (one for electron and one for positron) and two photons?

Thanks
No, absolutely not.
 
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  • #5
Orodruin said:
No, absolutely not.
Is the reason related to post #2? And maybe also related to conservation of energy and momentum?

Thanks
 

FAQ: Question about Feynman diagram showing annihilation

What is a Feynman diagram?

A Feynman diagram is a graphical representation used in particle physics to illustrate the interactions between subatomic particles. It depicts the paths of particles as lines, with vertices representing interactions such as collisions or decays. Feynman diagrams help visualize complex quantum processes and make calculations of scattering amplitudes more manageable.

What does annihilation mean in the context of particle physics?

Annihilation refers to a process in which a particle and its corresponding antiparticle collide and convert their mass into energy, typically in the form of photons (light particles). This process is described by the principles of quantum field theory and is a key aspect of interactions involving matter and antimatter.

How is annihilation represented in a Feynman diagram?

In a Feynman diagram, annihilation is typically represented by two incoming lines that converge at a vertex, indicating the interaction point where the particle and antiparticle annihilate. The outgoing lines from the vertex often depict the resulting particles, such as photons, produced from the annihilation process.

What particles are commonly involved in annihilation processes?

Common particles involved in annihilation processes include electrons and positrons (the antiparticle of electrons), as well as protons and antiprotons. Other examples include mesons and their antiparticles. The annihilation of these particles results in the production of high-energy photons or other particle-antiparticle pairs.

What are some physical phenomena that can be explained by annihilation processes?

Annihilation processes are fundamental to understanding various physical phenomena, including the production of gamma rays in electron-positron annihilation, the behavior of matter and antimatter in the universe, and the energy release in particle collisions at high-energy physics experiments, such as those conducted at particle accelerators like the Large Hadron Collider.

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