How to search Feynman diagrams for entanglement This question is partly about physics, partly about love -- but I don't believe there's a Stack Exchange for the later :)
My girlfriend is a PhD physicist who finds the notion of entanglement very romantic. For her birthday, I taught myself the basics of jewelry making and crafted a necklace of the Feynman diagram for electron-positron annihilation, which makes two entangled virtual photons at low energy, if I understand it correctly:

(Not to scale. It's 2.54cm tall, 4cm wide)
For the next gift-giving occasion I want to make another one, ideally more precise. But I don't want to use the same diagram if possible. So my question is: What are some other subatomic interactions that produce two entangled particles?
I think it naturally follows that simpler diagrams are better, given my talents with a silver saw. While I'm eager for suggestions, I'm also curious if there's a way to search for such interactions in an efficient manner. This is the sort of thing Google doesn't really live up to. Is there an encyclopedia of Feynman diagrams coded by things like "entanglement"? 
Also, does anyone have a butane torch I can borrow? Kidding. Thx!
 A: This is sweet, but almost all interactions will produce entangled particles, and you've already used one of the most direct examples. Here are some random ideas that might help.


*

*Just try another Feynman diagram. You could use gluons, which would replace the inner line with a wavy one. You could use an $s$-channel or $u$-channel exchange process, rather than the $t$-channel you used here. You could also draw a decay, which is simpler (just a metal $Y$) but also produces entangled particles.

*Going a bit further away from the entanglement theme, you can draw a loop diagram. For example, a "one-loop" diagram would have another photon going parallel to the exchanged particle in your example. One-loop diagrams are used to compute to higher precision than no-loop diagrams, which might be nice if your metalworking precision has improved as well.

*Going even further away from the theme, you could try a themed animal Feynman diagram like a penguin diagram. You could also try a tadpole diagram, also called a spermion.

*Going away from particle physics, you could use a CNOT gate, one of the simplest gates used in quantum computing to generate entanglement. 

*Alternatively, in topological quantum computing, you can generate entanglement by braiding particles. Look up the braid group for graphical examples.

