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Hi!, Im studying for an introductory course in QED and Feynman Diagrams. Everything we see is like a first order approach and im having some trouble understanding antiparticles in Feynman Diagrams:

Why is it that we put an antiparticle that is leaving as if it is entering the interaction??

This is:

We have the interaction term:

[tex]\bar{\Phi}\gamma^{\mu} \Phi A_{\mu}[/tex]

From which I understood that [tex]\bar{\Phi}[/tex] corresponds to the outgoing particle. Yet for antiparticles we draw them as entering.

Also, i dont fully understand why we use the adjoint (i.e: with [tex]\gamma^0[/tex] multiplying) as the outgoing particles. I thought we were calculating interactions elements for the Hamiltonian. I dont know where the [tex]\gamma^0[/tex] comes from.

Sorry for my english.

Why is it that we put an antiparticle that is leaving as if it is entering the interaction??

This is:

We have the interaction term:

[tex]\bar{\Phi}\gamma^{\mu} \Phi A_{\mu}[/tex]

From which I understood that [tex]\bar{\Phi}[/tex] corresponds to the outgoing particle. Yet for antiparticles we draw them as entering.

Also, i dont fully understand why we use the adjoint (i.e: with [tex]\gamma^0[/tex] multiplying) as the outgoing particles. I thought we were calculating interactions elements for the Hamiltonian. I dont know where the [tex]\gamma^0[/tex] comes from.

Sorry for my english.

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