Question about Feynman diagram showing annihilation

AI Thread Summary
The discussion centers on a Feynman diagram depicting annihilation, specifically questioning the significance of a middle line with an arrow pointing right. It is clarified that this line represents an electron, not a W boson, as a W-line would violate Lorentz and electroweak gauge symmetries. The possibility of removing the horizontal line to simplify the diagram is dismissed, emphasizing that it is essential for maintaining conservation of energy and momentum. The conversation highlights the importance of accurately interpreting Feynman diagrams in particle physics. Understanding these diagrams is crucial for grasping fundamental interactions.
songoku
Messages
2,469
Reaction score
382
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
 
Physics news on Phys.org
It is an electron line.

A W-line would violate both Lorentz symmetry and electroweak gauge symmetry.
 
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
 
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.
 
Reply
  • Like
Likes songoku and pines-demon
Orodruin said:
No, absolutely not.
Is the reason related to post #2? And maybe also related to conservation of energy and momentum?

Thanks
 
Thread 'Minimum mass of a block'

Thread 'Minimum mass of a block'

Here we know that if block B is going to move up or just be at the verge of moving up ##Mg \sin \theta ## will act downwards and maximum static friction will act downwards ## \mu Mg \cos \theta ## Now what im confused by is how will we know " how quickly" block B reaches its maximum static friction value without any numbers, the suggested solution says that when block A is at its maximum extension, then block B will start to move up but with a certain set of values couldn't block A reach...
View full post »

Thread 'Electric field due to charges between 2 parallel infinite planes'

TL;DR Summary: Find Electric field due to charges between 2 parallel infinite planes using Gauss law at any point Here's the diagram. We have a uniform p (rho) density of charges between 2 infinite planes in the cartesian coordinates system. I used a cube of thickness a that spans from z=-a/2 to z=a/2 as a Gaussian surface, each side of the cube has area A. I know that the field depends only on z since there is translational invariance in x and y directions because the planes are...
View full post »

Similar threads

Is the Charge Conservation Correct in This Meson Decay Feynman Diagram?
Replies
8
Views
976
Is my Feynman diagram for production of ##W^-## boson correct?
Replies
5
Views
2K
I Confused about Feynman diagrams
Replies
10
Views
3K
I Electroweak Feynman Rules: Confusion about the photon-W boson interaction term
Replies
2
Views
2K
Feynman rules and the tree level cross section of two scalar fields
Replies
6
Views
2K
Feynman diagram for pair annihilation
Replies
5
Views
4K
Up, anti-up quark annihilation Feynman diagram
Replies
1
Views
5K
I Feynman diagrams and sum over paths
Replies
5
Views
2K
Electron-positron annihilation diagram
Replies
7
Views
5K
Confused about direction of electric field
Replies
7
Views
3K

Hot Threads

Recent Insights

Back
Top