The t anti-t production in pp collisions at vs=14 TeV

The proton proton collider LHC will operate at vs = 14 TeV center of mass energy which gives rise to a cross section of about 800 pb for the production of t¯t events. This leads, already for a start-up luminosity of L = 10^33 cm^-2s^-1, to a huge production rate of 8 * 10^6 t¯t events per year, corresponding to an integrated luminosity of 10 fb^-1. Simulations including the CMS detector response show the expected precision in the determination of the top quark mass to be 900 MeV. Moreover, the measurement of the W boson helicity with an expected uncertainty at a percent level and the measurement of the t¯t spin correlation with an expected uncertainty below 15 % will allow to test the standard model interactions. The prospect of observing a heavy Higgs boson in the t¯t decay channel is investigated. A non standard model Higgs boson without coupling to vector bosons, like the supersymmetric pseudo scalar Higgs, with a mass not too far above 400 GeV can be discovered (above the 5 sigma threshold) within less than half a year running at high luminosity (L = 10^34 cm^-2s^-1) under the assumption that the shape of the invariant mass spectrum and the cross section of the t¯t background is known to the percent level.