HARD BREMSSTRAHLUNG PHOTONS IN THE T(T)OVER-BAR PRODUCTION AND DECAY - A BACKGROUND FOR THE INTERMEDIATE HIGGS SEARCH

We discuss the radiation of hard photons in the ttBAR production and d ecay as a background for the intermediate Higgs search at LHC/SSC expe riments. For the purpose of experimental simulation of this process we propose to use the approximate Monte Carlo algorithm together with an y physics Monte Carlo not including QED corrections. We verify, by com parison with the exact matrix element Monte Carlo TOPKI, that this met hod can be used to generate single- and double-photon bremsstrahlung i n the ttBAR production process with a precision of 10% for experimenta l cuts. The predictions for the gammagammal background from photons ra diated in the production of ttBAR pair and their cascade decays, withi n simplified experimental cuts, are presented for the first time. We s how that, even after additional cuts on the minimal lepton-photon mass , photons radiated in the production and decay of a ttBAR pair increas e this background by a factor of 2 with respect to previous estimates from radiation in the ttBAR production alone.