Enhancing the $t \bar t H$ signal through top-quark spin polarization effects at the LHC

We consider the impact of the tt‾ spin correlations in the Higgs boson production in association with top quark pairs pp→tt‾H and in the corresponding backgrounds. We study the H→bb‾ and H→γγ decay modes. We show that retaining the tt‾ spin-correlation effects could significantly improve the LHC sensitivity to the tt‾H signal, particularly in the H→γγ channel.