Effects of Amplitude Nullification in the Standard Model

Abstract

Delicate cancellations among diagrams can result in the vanishing of threshold amplitudes in the standard model. This phenomenon is investigated for multi-Higgs production by scalar, vector, and fermionic fields. A surprising gap is found where although the tree-level amplitude for $2$ incoming gauge bosons to produce $N_v$ particle may vanish, the amplitude for the production of $N_v+1$ particles is nonzero.

Comments: 10, 10 pages