Higgs boson production at a photon linear collider.

Abstract

The collision of high-energy, high-intensity photon beams would provide novel opportunities for particle physics. These beams could be obtained at a linear ${e}^{+}{e}^{\ensuremath{-}}$ collider via Compton backscattering using high-powered lasers. The resulting photon linear collider offers highly polarized beams, large luminosities, and a variable luminosity spectrum. We examine the potential of such a machine to explore the Higgs sector of the standard model. We find a photon linear collider with $\sqrt{s}\ensuremath{\approx}250$ GeV to be an excellent tool to search for an intermediate-mass Higgs boson, with the polarized photon beams being a particular asset, as they can be used to suppress backgrounds while enhancing the signal. In searching for intermediate-mass standard model Higgs bosons, a signal in excess of $10\ensuremath{\sigma}$ over the entire intermediate mass region is possible with even moderate luminosity. Even more important is the application of a photon linear collider to measurement of the two-photon width of the Higgs boson, a measurement which gives crucial information about the nature of spontaneous symmetry breaking. We calculate that a photon linear collider with energy tuned to the Higgs boson mass allows a measurement of the two-photon width of the Higgs boson with a statistical precision of better than 10% over most of the intermediateand heavy-mass range.