© David Kaplan.
The top three Feynman diagrams represent part of a calculation of the quantum effects on the Higgs mass (and therefore W and Z masses). The result is nonsense (infinity), suggesting that there are other unknown contributions which make the result sensible (finite). In a theory with supersymmetry and supersymmetric partners of the Standard Model particles, one must include additional diagrams, such as the lower two diagrams, which include the superpartners of the Higgs, W boson, and top quarks. While by no means are they guaranteed, the inclusion of this symmetry and these extra particles get these corrections under control. (Unit: 2)