Pheno seminar / JC

We study the process l−l+ → ννˉZh for future lepton colliders, whose cross section exceeds that of l−l+ → Zh in the multi-TeV energy region. The amplitudes are classified into three main groups according to the topology of the Feynman diagrams, and their interference patterns are analyzed. We show that the subtle gauge cancellations present at high energies in the unitary gauge are absent in the recently proposed Feynman-diagram gauge, allowing the physical distributions to be interpreted in terms of contributions from each subgroup.