\b[Allowed.] There are again two <tree-level Feynman diagrams>: $t$-channel <Z boson> exchange and the crossed charged-current diagram with a <W boson> exchanged between the neutrino and electron lines.

The complete tree-level list for (ii), (iv), and (v) is:

\Image[/media/past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2019/iii/paper-305-standard-model-processes.png]
{height=800}

Solution

Past exam of the mathematics course of the University of Cambridge / 2019 / iii / Paper 305 / 3 / a / v / Solution

 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2019/iii/paper-305/3/a/v/solution