Calculation of the contributions to the signals and backgrounds for intermediate mass Higgs detection at the LHC and SSC from the qq initial state

Abstract We calculate the subprocess q q →t t H which contribute to the signal for detection of a light “intermediate mass” Higgs boson at the LHC and SSC in the isolated lepton and two isolated photons mode. This enhances the gg→t t H signal by about 10% at the SSC and 25% at the LHC. We also calculate the q q →t t γγ irreducible background sugprocess to this detection mode which enhances the gg→t t γγ irreducible background. This background is found to be quite substantial due to the effect of radiation from the initial state quarks as well as the final state t t pair; at the SSC the g g initial state background enhances the gg initial state background by between 20% for mt=100 GeV and 35% for mt=180 GeV, and the LHC by between 50% for mt=100 GeV and 120% for mt=180 GeV. However with a 3% mass resolution on the γγ mass the extra q q background events are typically smaller than extra q q signal events, and the signal remains observable.