We start by reviewing the discrete symmetries of the Standard model, focusing on CP symmetry more specifically. We show that CP symmetry violation is an essential component to create the baryon asymmetry in universe as we see today. That is the motivation to search for CP symmetry violation in physics beyond the Standard model. Experimental measures of B mesons hint of new physics in semileptonic decay of b quarks to c quarks. We propose two new dimension six operators in the $\tau$ lepton flavor sector. With this we get two new interactions with couplings $g_S$ and $g_T$. These two coupling constants are complex in general and thus violate the CP symmetry. In order to probe the two coupling constants on a proton collider we construct angular observables $\Delta\omega$ at parton level of proton collision process,
that produces quarks b and c and leptons $\tau$ and $\nu_\tau$. These observables are sensitive to the relative complex phase between the two coupling constants. Using the allowed region in $g_S$ $g_T$ parameter space, we predict $\Delta \omega$ and its statistical significance that would be observed in future LHC runs.
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