Producing an Intense, Cool Muon Beam via e+e- Annihilation

We consider a highly unconventional approach to generating muon and antimuon bunches for a neutrino factory or muon collider: electron-positron annihilation just above muon-antimuon threshold. This approach can produce low-emittance bunches at high energy, easing the muon-cooling and acceleration challenges in such facilities. However, the small (< 1 $\mu$b) useable production cross section means that extraordinary beam-power and targeting challenges would have to be met. We speculate on what this might entail.