Higgs Production at

\nMotivated by recent advancements in antimuon cooling, we consider Higgs boson production at µ+µ+ colliders. The leading-order W+W− fusion process present at, e.g., µ+µ− colliders does not occur since both intial-state particles carry the same charge. Nevertheless, Higgs production is possible via a higher-order process mediated by a photon or Z boson. We find that at high energies, the associated cross secction grows as (log s)3 with the center-of-mass energy √s, as opposed to the log s growth of the leading-order process at µ+µ− colliders. Thus, the higher-order cross section with polarized beams can become about half as large as the leading-order process at µ+µ− colliders at O(10) TeV energies, despite its naive suppression. When calculating the higher-order cross section, collinear photon emissions make direct computations using event generators difficult. We therefore treat these emissions by splitting the phase-space into the sum of a non-collinear region calculable using event generators, and a collinear region approximated by a parton distribution function for the photon. Furthermore, since the same process can occur at any high-energy lepton collider, this large cross section needs to be considered also for Higgs production at µ+µ− and e+e− colliders.\n