$$ p+\Lambda^{0} \to n+\Sigma^{0} $$

So, I am trying to draw a Feynman diagram for the written interaction. Baryon number is conserved, charge is conserved, so that works. When I look at the quarks, I see that only one up quark changes to down quark, but still do not manage to see how to draw it. Because with the strong force quark should only change color, but nothing can come out from gluon. Or maybe this is impossible?

  • $\begingroup$ Charge is not conserved in this reaction. $\endgroup$
    – G. Smith
    Jul 3, 2019 at 21:51

1 Answer 1


The weak interaction can change quarks, for instance, see the CKM quark mixing matrix: https://en.wikipedia.org/wiki/Cabibbo%E2%80%93Kobayashi%E2%80%93Maskawa_matrix

  • $\begingroup$ It can, but I do not see how is it possible here, to have everything else sustained. $\endgroup$ Jul 3, 2019 at 21:40
  • 1
    $\begingroup$ Oh. For your specific reaction, electric charge is not conserved so it can not proceed. If you added a positron and a neutrino to the right-hand side, then you're in business. $\endgroup$
    – Kent
    Jul 3, 2019 at 21:42
  • $\begingroup$ Indeed, so simple. Can not believe how I missed this. Thanks! $\endgroup$ Jul 3, 2019 at 21:55

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