KIP-Veröffentlichungen

A search for γγ decays of a Higgs boson is performed in the data sample collected at LEP with the ALEPH detector between 1991 and 1999. This corresponds to an integrated luminosity of 672 pb^-1 at centre-of-mass energies ranging from 88 to 202 GeV. The search is based on topologies arising from a Higgs boson produced in association with a fermion pair via the Higgs-strahlung process e⁺e^-→Hff^-, with ff=νν^-, e⁺e^-,μ⁺μ^-,τ⁺τ^- or qq^-. Twenty-two events are selected in the data, while 28 events are expected from standard model processes. An upper limit is derived, as a function of the Higgs boson mass, on the product of the eqey™Hff cross section and the H→γγ branching fraction. In particular, a fermiophobic Higgs boson produced with the standard model cross section is excluded at 95% confidence level for all masses below 100.7 GeV/c².