The main source of \epe pair at μ+μ− collider is incoherent process μ+μ−→μ+μ−\epe with cross section about 10 mb (at muon energy 2 TeV). The corresponding distributions are discussed briefly. These pairs give the dangerous background. The coherent production of \epe pairs here is negligibly small.
@article{arxiv.hep-ph/9601273,
title = {The $e^+e^-$ pair production at $\mu^+\mu^-$ collider},
author = {Ilya F. Ginzburg},
journal= {arXiv preprint arXiv:hep-ph/9601273},
year = {2007}
}