The ttH analyses at the LHC

Detecting the presence of a light Higgs boson at the LHC is very difficult. For this reason, different experimental signatures will have to be combined to ensure its discovery. Among them we study the associate production with a pair of top quarks and the subsequent Higgs boson decay into b quark pairs, the dominant decay mode for m_H < 135 GeV/c^2. This channel allows an accurate estimation of the top quark Yukawa coupling within the Standard Model. We present several observability studies of the ttH(H -> bb) channel with the ATLAS and the CMS detectors. In addition, the decay modes H -> WW and H -> gamma gamma in ttH processes have been investigated and are briefly reported at the end of this paper.