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Most important Feynman diagrams

  1. Sep 9, 2011 #1
    what do you think are the most important Feynman diagrams (or probably better: what do you think are the most important processes in particle physics)?
    Quantum Cosmo
  2. jcsd
  3. Sep 9, 2011 #2


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    This is a pretty weird question, Cosmo. Like, what is your favorite nucleus?
  4. Sep 9, 2011 #3


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    That's easy. Radioactive calcium.
  5. Sep 9, 2011 #4
    Tadpoles, easily.
  6. Sep 9, 2011 #5


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    Ah, if only they had gone with the other name. The Journal where Coleman first published this rejected the name 'tadpoles' and insisted he change it. He sent back the alternative: 'spermions'. They accepted tadpoles.
  7. Sep 9, 2011 #6
    Penguin diagrams - they'd beat tadpoles in a fight any day of the week.

    An attempt at a serious answer...

    Tree level diagrams - since they dominate most effects.

    Loop diagrams where new physics appears:
    Eg 1-loop box diagram in QED that leads to photon-photon interactions.

    Of course, one-loop is only semi-classical. I remember that some stuff first happens at two loops, but can't remember what it is off the top of my head.
  8. Sep 10, 2011 #7
    True, that beats tadpoles!
  9. Sep 11, 2011 #8


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    Staff: Mentor

    I can think of a certain regular poster to PF whose favorite Feyman diagram is surely the penguin! :biggrin:
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