Non-linear top-Higgs CP violation

Searches for additional sources of CP violation at the Large Hadron Collider are a central part of the Higgs physics programme beyond the Standard Model. Studies employing so-called signed observables that track CP violation through purpose-built asymmetries bolster efforts based on Higgs boson rate analyses under clear assumptions. A possibility, which is so far unexplored at the LHC, is a significant non-linear realisation of CP-violation, which is naturally described in non-linear Higgs Effective Field Theory (HEFT). We perform an analysis of the HL-LHC potential to constrain such interactions considering a large range of single and double Higgs production processes, including differential information where this is statistically and theoretically possible. A particular emphasis of our work is distinguishing expected correlations in the Standard Model Effective Field Theory from those attainable in HEFT.