Sketch the sixth-order Feynman diagram representing Delbruck scattering:
r + r -> r+ r. (This process, the scattering of light by light, has no analog in classical electrodynamics.)
This question is from the textbook 'Introduction to elementary particles' by David Griffiths.© BrainMass Inc. brainmass.com August 21, 2018, 1:49 pm ad1c9bdddf
I did manage to open the sixth.jpg file after downloading it.
I have added to it the 3 topologically different 6th order diagrams for photon-photon scattering and an example of a different variant of one of them.
As I noted before it is not clear from your question whether you need all the variants (in particular, the A and B have their obvious variants in which electron ...