Disentangling Higgs-top couplings in associated production

In the presence of CP violation, the Higgs-top coupling may have both scalar and pseudoscalar components, kappa(t) and (kappa) over tilde (t), which are bounded indirectly but only weakly by the present experimental constraints on the Higgs-gluon-gluon and Higgs-gamma-gamma couplings, whereas upper limits on electric dipole moments provide strong additional indirect constraints on (kappa) over tilde (t), 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 (t) over bart, single t and single (t) over bar 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 (t) over bar tH, tH and (t) over barH final states. We also investigate the additional information on kappa(t) and (kappa) over tilde (t) that could be obtained from measurements of the longitudinal and transverse t polarization in the different associated production channels, and the (t) over bart spin correlation in (t) over bar tH events.