Disentangling Higgs-top couplings in associated production

Abstract

In the presence of CP violation, the Higgs-top coupling may have both scalar and pseudoscalar components, t and ∼, which are bounded indirectly but only weakly by the present experimental constraints on the Higgs-gluon-gluon and Higgs-γ-γ couplings, whereas upper limits on electric dipole moments provide strong additional indirect constraints on ∼, if the Higgs-electron coupling is similar to that in the Standard Model and there are no cancellations with other contributions. We discuss methods to measure directly the scalar and pseudoscalar Higgs-top couplings by measurements of Higgs production in association with t̄t, single t and single t̄ at the LHC. Measurements of the total cross sections are very sensitive to variations in the Higgs-top couplings that are consistent with the present indirect constraints, as are invariant mass distributions in t̄tH, tH and t̄H final states. We also investigate the additional information on t and ∼ that could be obtained from measurements of the longitudinal and transverse t polarization in the different associated production channels, and the t̄t spin correlation in t̄tH events. © 2014 The Author(s).