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Homework Help: Feynman diagram; ##\pi^0+\pi^0\rightarrow \pi^++\pi^-##

  1. Feb 11, 2016 #1
    1. The problem statement, all variables and given/known data

    For the reaction below draw three Feynman diagrams, one that proceeds through
    exchange of a gluon, one through a photon and one exchanging a weak W-Boson.

    ##\pi^0+\pi^0\rightarrow \pi^++\pi^-##

    Which diagram provides the dominant contribution for this reaction?
    Explain how the electromagnetic force can work on an electrically neutral particle like the ##\pi^0##.

    2. Relevant equations

    3. The attempt at a solution

    First of all i'm confused by the composition of the $\pi^0$ meson, do I use $d\bar{d}$ or $u\bar{u}$? I would think that for one neutral pion I use $d\bar{d}$ and the other I use $u\bar{u}$ since this gives the constituent quarks for the products. But then I have no idea how to begin drawing the interaction and how the virtual particle changes the diagram. I apologise since I am very new to Feynman diagrams. Here is an attempt for the W boson:

    Neutral pion interaction.png
  2. jcsd
  3. Feb 12, 2016 #2


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    2017 Award

    Staff: Mentor

    You can use either.

    The W diagram is fine (what is that to the upper right of the "W"?).
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