Speaker
Description
We investigate the anomalous $t \bar{t} Z$ couplings in the Standard Model (SM) and measure the precision of couplings beyond the SM in future electron-proton collider environments. In the analysis, $t \bar{t}$ quark pairs are produced in the neutral currents channel through the collision process $e^{-} p \to e^{-} t \bar{t}$, for electron and proton (unpolarized) beam-energies $E_{e}=60$ GeV and $E_p=7$ TeV respectively, at a combined center-of-mass energy of 1.3 TeV as proposed for the Large Hadron-electron Collider. Each of the top quarks in the $t \bar{t}$ pair can decay through the leptonic or the hadronic mode resulting in either the leptonic, hadronic, or semileptonic final states. Sensitive angular observables are utilized to measure and constrain the $t \bar{t} Z$ couplings. We find that the azimuthal angle difference, $\Delta \phi$, between the top quarks decay products, and that of each top quark with the scattered electron in the semileptonic final state are most sensitive and viable angular observable for constraining the couplings. We perform a $\chi^2$ analysis based on the azimuthal difference to constrain the couplings.
