Abstract
We compare the impact of top-quark spin polarization effects in Higgs boson production in association with top-quark pairs and in corresponding backgrounds at the LHC. Because of the spin-zero nature of the Higgs boson, one expects, in the chiral limit for the top quarks, a substantial complementarity in \( t\overline{t} \) spin correlations for a Higgs decaying into fermions/gauge-bosons and \( t\overline{t} \) spin correlations for the corresponding irreducible \( t\overline{t} f\overline{f} \)/VV backgrounds. Although top mass effects in \( t\overline{t} H \) production are in general dominant, and seriously spoil the chiral-limit expectations, one can find observables that capture the \( t\overline{t} \) angular spin correlations and can help in separating the signal from irreducible backgrounds. In particular, we show that, for both H → \( b\overline{b} \) and H → γγ, taking into account \( t\overline{t} \) spin correlations in \( t\overline{t} H \) production and irreducible backgrounds could appreciably improve the LHC sensitivity to the \( t\overline{t} H \) channel.
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Biswas, S., Frederix, R., Gabrielli, E. et al. Enhancing the \( t\overline{t} H \) signal through top-quark spin polarization effects at the LHC. J. High Energ. Phys. 2014, 20 (2014). https://doi.org/10.1007/JHEP07(2014)020
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DOI: https://doi.org/10.1007/JHEP07(2014)020