Abstract
We analyze the prospects of probing the C P -odd \( i\tilde{\kappa}\overline{t}\gamma \)5th interaction at the LHC and its projected upgrades, the high-luminosity and high-energy LHC, directly using associated on-shell Higgs boson and top quark or top quark pair production. To this end we first construct a C P -odd observable based on top quark polarization in Wb → th scattering with optimal linear sensitivity to \( \tilde{\kappa} \). For the corresponding hadronic process pp → thj we present a method of extracting the phase-space dependent weight function that allows to retain close to optimal sensitivity to \( \tilde{\kappa} \). We project future sensitivity to the signal in pp → t(→ ℓ𝜈b)h(→ b\( \overline{b} \))j. We also propose novel C P -odd observables for top quark pair production in association with the Higgs, pp → t\( \overline{t} \)h, with semileptonically decaying tops and h → b\( \overline{b} \), that rely solely on measuring the momenta of leptons and b-jets from the decaying tops without having to distinguish the charge of the b-jets. Among the many possibilities we single out an observable that can potentially probe \( \tilde{\kappa} \) ∼ 0.1 at the high-energy LHC with 2𝜎 confidence.
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Faroughy, D.A., Kamenik, J.F., Košnik, N. et al. Probing the C P nature of the top quark Yukawa at hadron colliders. J. High Energ. Phys. 2020, 85 (2020). https://doi.org/10.1007/JHEP02(2020)085
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DOI: https://doi.org/10.1007/JHEP02(2020)085