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

Enhancing the ttH signal through top-quark spin polarization effects at the LHC

GABRIELLI, Emidio;
2014

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 tt¯ spin correlations for a Higgs decaying into fermions/gauge-bosons and tt¯ spin correlations for the corresponding irreducible tt¯ff¯/VV backgrounds. Although top mass effects in tt¯H production are in general dominant, and seriously spoil the chiral-limit expectations, one can find observables that capture the tt¯ angular spin correlations and can help in separating the signal from irreducible backgrounds. In particular, we show that, for both H→bb¯ and H→γγ, taking into account tt¯ spin correlations in tt¯H production and irreducible backgrounds could appreciably improve the LHC sensitivity to the tt¯H channel.
http://dx.doi.org/10.1007/JHEP07(2014)020
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11368/2829814
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