Loop-induced Higgs boson pair production at e+e- colliders.

Abstract

We analyze the loop-induced production of Higgs boson pairs at future high-energy ${e}^{+}{e}^{\ensuremath{-}}$ colliders, both in the standard model and in its minimal supersymmetric extension. The cross sections for standard model Higgs pair production through $\frac{W}{Z}$ boson loops, ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{H}^{0}{H}^{0}$, are rather small but the process could be visible for high enough luminosities, especially if longitudinal polarization is made available. In the minimal supersymmetric standard model, the corresponding processes of $\mathrm{CP}$-even or $\mathrm{CP}$-odd Higgs boson pair production, ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}hh, HH, \mathrm{Hh}$, and ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}\mathrm{AA}$, have smaller cross sections, in general. The additional contributions from chargino or neutralino and slepton loops are at the level of a few percent in most of the supersymmetric parameter space.