TracingCPviolation in the production of top quark pairs by multiple TeV proton-proton collisions

We investigate the possibilities of searching for nonstandard $\mathrm{CP}$ violation in $\mathrm{pp}\to t\overline{t}X$ at multiple TeV collision energies. A general kinematic analysis of the underlying partonic production processes $\mathrm{gg}\to t\overline{t}$ and $q\overline{q}\to t\overline{t}$ in terms of their density matrices is given. We evaluate the $\mathrm{CP}$-violating parts of these matrices in two-Higgs-doublet extensions of the standard model (SM) and give results for $\mathrm{CP}$ asymmetries at the parton level. We show that these asymmetries can be traced by measuring suitable observables constructed from energies and momenta of the decay products of $t$ and $\overline{t}$. We find $\mathrm{CP}$-violating effects to be of the order of ${10}^{-3\mathrm{}}$ and show that possible contaminations induced by SM interactions are safely below the expected signals.