Extracting the intermediate-mass Higgs resonance at photon-photon colliders.

Abstract

We address the problem of how to extract the signal of a Higgs boson within the intermediate mass range at a photon-photon collider that has a wide energy spectrum. All backgrounds from two-jet production are included: direct, so-called resolved and twice-resolved, as well as single Z and W production. Uncertainties in the evaluation of the QCD-initiated processes such as the choice of structure function and the issue of radiative corrections are discussed. We consider various combinations of the polarizations and invariant mass resolutions as well as jet-tagging strategies with different efficiencies. The analysis is based on an automatized technique that, given a specific detector and machine configuration, returns the optimal set of cuts corresponding to the best significance one may hope to achieve for each particular Higgs boson mass. We find that at a photon machine obtained from a 500 GeV ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ linear collider with FscrL=10 ${\mathrm{fb}}^{\mathrm{\ensuremath{-}}1}$ it will be possible to extract a Higgs signal in the range 110--140 GeV, while with the same luminosity, a 350 GeV option not only extends the discovery limit down to 90 GeV but gives much better significance levels.