Enhancing the tn n tn ¯n n Hn n n n signal through top-quark spin polarization effects at the LHC

摘要

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 ( toverline{t} ) spin correlations for a Higgs decaying into fermions/gauge-bosons and ( toverline{t} ) spin correlations for the corresponding irreducible ( toverline{t} foverline{f} )/VV backgrounds. Although top mass effects in ( toverline{t} H ) production are in general dominant, and seriously spoil the chiral-limit expectations, one can find observables that capture the ( toverline{t} ) angular spin correlations and can help in separating the signal from irreducible backgrounds. In particular, we show that, for both H → ( boverline{b} ) and H → γγ, taking into account ( toverline{t} ) spin correlations in ( toverline{t} H ) production and irreducible backgrounds could appreciably improve the LHC sensitivity to the ( toverline{t} H ) channel