Pseudoscalar top-Higgs coupling: Exploration of $\mathrm{CP}$-odd observables to resolve the sign ambiguity

Understand

We present a collection of $\mathrm{CP}$-odd observables for the process $pp\to t\,\left(\rightarrow b {\ell}^+ \nu_{\ell}\right) \bar{t}\,\left(\rightarrow \bar{b} {\ell}^-{\bar{\nu}}_{\ell}\right)\,H$ that are linearly dependent on the scalar ($\kappa_t$) and pseudoscalar ($\tilde{\kappa}_t$) top-Higgs coupling and hence sensitive to the corresponding relative sign.

• The proposed observables are based on triple product (TP) correlations that we extract from the expression for the differential cross section in terms of the spin vectors of the top and antitop quarks.
• In order to explore other possibilities, we progressively modify these TPs, first by combining them, and then by replacing the spin vectors by the lepton momenta or the $t$ and $\bar{t}$ momenta by their visible parts.
• We generate Monte Carlo data sets for several benchmark scenarios, including the Standard Model ($\kappa_t=1$, $\tilde{\kappa}_t=0$) and two scenarios with mixed $\mathrm{CP}$ properties ($\kappa_t=1$, $\tilde{\kappa}_t=\pm 1$).