  A search for a narrow diphoton mass resonance is presented based on data from
3.0 fb^{-1} of integrated luminosity from p-bar p collisions at sqrt{s} = 1.96
TeV collected by the CDF experiment. No evidence of a resonance in the diphoton
mass spectrum is observed, and upper limits are set on the cross section times
branching fraction of the resonant state as a function of Higgs boson mass. The
resulting limits exclude Higgs bosons with masses below 106 GeV at a 95%
Bayesian credibility level (C.L.) for one fermiophobic benchmark model.
