W-boson pair production at lepton colliders in the Feynman-diagram gauge

Abstract

We calculate helicity amplitudes for $e^{-}{e}^{+}\to W^{-}{W}^{+}$ analytically in the Feynman-diagram (FD) gauge. We show that, unlike in the unitary gauge, there is no energy growth of the individual Feynman amplitudes for the longitudinally polarized W bosons, and the contributions from the associated Goldstone bosons are manifest even without taking the high-energy limit. We also find that the physical distributions can be interpreted by the individual amplitudes in the FD gauge.

Comments: 7 pages, 3 Tables, 6 figures; v2: version published in PRD