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I have to draw a Feynman diagram for the interaction of a deuteron with Oxygen-16.

The interaction is as follows:

$ d + {}^{16}O \rightarrow p + {}^{17}O . $

I am generally ok with Feynman diagrams when I know what particles are actually interacting - proton, neutron etc. but I am not sure how to proceed when an actual element such as oxygen in given. Any help would be much appreciated.

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Protons are composite particles, right? Yet you're comfortable with the fact that at sufficiently low energy you can draw them as lines in a Feynman diagram. So why would nuclei be any different? :) – Michael Brown Apr 4 '13 at 11:07
So can I really just leave Oxygen-16 and Oxygen-17 as lines in the Feynman diagram? Am I right in saying the interaction is a weak interaction? – user49394 Apr 4 '13 at 12:46
Yes, you can draw them as lines. If you like you can draw them as a bundle of closely packed lines to indicate the individual nucleons, or a single line leading into a blob for the interactions (like here). However you draw them: follow the deuteron line in to the interaction vertex. It comes out as either the final proton ($t$ channel), ${}^{17}O$ ($u$ channel) or intermediate ${}^{18}F$ ($s$ channel), so there is a transfer of baryon number either way. Weak interactions can't mediate that. You've gotta have a transfer of some kind of nucleon(s). – Michael Brown Apr 4 '13 at 13:43

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